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Rule2023-03982

Energy Conservation Program: Test Procedure for Consumer Boilers

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Published

March 13, 2023

Effective

April 12, 2023

Issuing agencies

Energy Department

Abstract

The U.S. Department of Energy ("DOE") amends its test procedure for consumer boilers established under the Energy Policy and Conservation Act. This rulemaking fulfills DOE's obligation to review its test procedures for covered products at least once every seven years. The revisions include: incorporating by reference the latest versions of the industry standards currently referenced in the Federal test procedure; relocating the test procedure to a new appendix separate from the residential furnace test procedure; removing an extraneous definition from its regulatory definitions; and making clarifying corrections to calculations. These revisions will improve the representativeness of the test method and will not be unduly burdensome to conduct.

Full Text

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<title>Federal Register, Volume 88 Issue 48 (Monday, March 13, 2023)</title>
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[Federal Register Volume 88, Number 48 (Monday, March 13, 2023)]
[Rules and Regulations]
[Pages 15510-15555]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-03982]

[[Page 15509]]

Vol. 88

Monday,

No. 48

March 13, 2023

Part II

Department of Energy

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10 Part 429, 430

Energy Conservation Program: Test Procedure for Consumer Boilers; Final
Rule

Federal Register / Vol. 88 , No. 48 / Monday, March 13, 2023 / Rules
and Regulations

[[Page 15510]]

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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 430

[EERE-2019-BT-TP-0037]
RIN 1904-AE83

Energy Conservation Program: Test Procedure for Consumer Boilers

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of
Energy.

ACTION: Final rule.

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SUMMARY: The U.S. Department of Energy (``DOE'') amends its test
procedure for consumer boilers established under the Energy Policy and
Conservation Act. This rulemaking fulfills DOE's obligation to review
its test procedures for covered products at least once every seven
years. The revisions include: incorporating by reference the latest
versions of the industry standards currently referenced in the Federal
test procedure; relocating the test procedure to a new appendix
separate from the residential furnace test procedure; removing an
extraneous definition from its regulatory definitions; and making
clarifying corrections to calculations. These revisions will improve
the representativeness of the test method and will not be unduly
burdensome to conduct.

DATES: The effective date of this rule is April 12, 2023. The
amendments will be mandatory for product testing starting September 11,
2023.
The incorporation by reference of certain material listed in the
rule is approved by the Director of the Federal Register as of April
12, 2023. The incorporation by reference of certain other material
listed in the rule was approved by the Director of the Federal Register
on March 23, 2009, and February 16, 2016.

ADDRESSES: The docket, which includes Federal Register notices, public
meeting attendee lists and transcripts, comments, and other supporting
documents/materials, is available for review at <a href="http://www.regulations.gov">www.regulations.gov</a>.
All documents in the docket are listed in the <a href="http://www.regulations.gov">www.regulations.gov</a>
index. However, not all documents listed in the index may be publicly
available, such as those containing information that is exempt from
public disclosure.
A link to the docket web page can be found at <a href="http://www.regulations.gov/docket/EERE-2019-BT-TP-0037">www.regulations.gov/docket/EERE-2019-BT-TP-0037</a>. The docket web page contains instructions
on how to access all documents, including public comments, in the
docket.
For further information on how to review the docket, contact the
Appliance and Equipment Standards Program staff at (202) 287-1445 or by
email: <a href="/cdn-cgi/l/email-protection#5b1a2b2b37323a35383e082f3a353f3a293f28673a7b33293e3d66" mailto:Questions@ee.doe.gov">[email&#160;protected]</a>">ApplianceStandards<a href="/cdn-cgi/l/email-protection#d687a3b3a5a2bfb9b8a596b3b3f8b2b9b3f8b1b9a0">[email&#160;protected]</a></a>.

FOR FURTHER INFORMATION CONTACT:
Ms. Julia Hegarty, U.S. Department of Energy, Office of Energy
Efficiency and Renewable Energy, Building Technologies Office, EE-2J,
1000 Independence Avenue SW, Washington, DC 20585-0121. Telephone:
(240) 597-6737. Email: <a href="/cdn-cgi/l/email-protection#ce8fbebea2a7afa0adab9dbaafa0aaafbcaabdf2afeea6bcaba8f3" mailto:Questions@ee.doe.gov">[email&#160;protected]</a>">ApplianceStandards<a href="/cdn-cgi/l/email-protection#3564405046415c5a5b467550501b515a501b525a43">[email&#160;protected]</a></a>.
Ms. Amelia Whiting, U.S. Department of Energy, Office of the
General Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC
20585-0121. Telephone: (202) 586-2588. Email:
<a href="/cdn-cgi/l/email-protection#febf939b92979fd0a996978a979099be968fd09a919bd0999188">[email&#160;protected]</a>.

SUPPLEMENTARY INFORMATION: DOE maintains material previously approved
for incorporation by reference in part 430: ANSI/ASHRAE 103-1993 and
ASTM D2156-09 (Reapproved 2013). DOE incorporates by reference the
following industry standards into 10 CFR part 430:
ANSI/ASHRAE Standard 41.6-2014, ``Standard Method for Humidity
Measurement,'' ANSI-approved July 3, 2014 (``ASHRAE 41.6-2014'').
ANSI/ASHRAE 103-2017, ``Method of Testing for Annual Fuel
Utilization Efficiency of Residential Central Furnaces and Boilers,''
ANSI-approved July 3, 2017 (``ASHRAE 103-2017'').
Copies ofANSI/ASHRAE 41.6-2014 and ANSI/ASHRAE 103-2017 can be
obtained from the American Society of Heating, Refrigerating and Air-
Conditioning Engineers, Inc. (ASHRAE), 180 Technology Parkway NW,
Peachtree Corners, GA 30092, (800) 527-4723 or (404) 636-8400, or
online at <a href="http://www.ashrae.org">www.ashrae.org</a>.
ASTM International (``ASTM'') Standard D2156-09 (Reapproved 2018),
``Standard Test Method for Smoke Density in Flue Gases from Burning
Distillate Fuels,''approved October 1, 2018 (``ASTM D2156-09
(R2018)'').
Copies of ASTM D2156-09 (R2018) can be obtained from ASTM
International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken,
PA 19428-2959 or online at <a href="http://www.astm.org">www.astm.org</a>.
International Electrotechnical Commission (``IEC'') 62301,
``Household electrical appliances--Measurement of standby power,''
(Edition 2.0) 2011-01 (``IEC 62301'').
Copies of IEC 62301 can be obtained from the International
Electrotechnical Commission (``IEC''), 3 Rue de Varembe, Case Postale
131, 1211 Geneva 20, Switzerland; or online at webstore.iec.ch.
See section IV.N of this document for a further discussion of these
standards.

Table of Contents

I. Authority and Background
A. Authority
B. Background
II. Synopsis of the Final Rule
III. Discussion
A. Scope of Applicability
1. Combination Space/Water Heating Boilers
2. Heat Pump Boilers
B. Definitions
C. Metric
D. Updates to Industry Standards
1. ANSI/ASHRAE 103
2. IEC 62301 and ASTM D2156-09
E. Steady-State Efficiency for Condensing Modulating Boilers
F. Corrections and Clarifications
1. Off-Cycle Losses
2. Conversion Factor for British Thermal Units
3. Oil Pressure Instrumentation Error
4. Gas Inlet Conditions
5. Active Mode Electrical Energy Consumption
6. Circulator Pumps
7. Units With Draft Hoods or Draft Diverters
8. Rounding of AFUE
G. Other Test Procedure Topics
1. Outdoor Design Temperature
2. Ambient Conditions
3. Combustion Settings
4. Supplemental Test Instructions
5. Input Rates for Step Modulating Boilers
6. Return Water Temperature
7. Standby Mode and Off Mode Electrical Energy Consumption
8. Full Fuel Cycle Efficiency
9. Idle Losses
H. Alternative Efficiency Determination Methods
I. Certification Provisions for Cast-Iron Boilers
J. Effective and Compliance Dates
K. Test Procedure Costs
IV. Procedural Issues and Regulatory Review
A. Review Under Executive Orders 12866 and 13563
B. Review Under the Regulatory Flexibility Act
C. Review Under the Paperwork Reduction Act of 1995
D. Review Under the National Environmental Policy Act of 1969
E. Review Under Executive Order 13132
F. Review Under Executive Order 12988
G. Review Under the Unfunded Mandates Reform Act of 1995
H. Review Under the Treasury and General Government
Appropriations Act, 1999
I. Review Under Executive Order 12630
J. Review Under Treasury and General Government Appropriations
Act, 2001
K. Review Under Executive Order 13211
L. Review Under Section 32 of the Federal Energy Administration
Act of 1974
M. Congressional Notification
N. Description of Materials Incorporated by Reference
V. Approval of the Office of the Secretary

[[Page 15511]]

I. Authority and Background

Furnaces, which include consumer boilers, are included in the list
of ``covered products'' for which the U.S. Department of Energy
(``DOE'') is authorized to establish and amend energy conservation
standards and test procedures. (42 U.S.C. 6291(23); 42 U.S.C.
6292(a)(5)) DOE's energy conservation standards and test procedures for
consumer boilers are currently prescribed at 10 CFR 430.32(e)(2) and 10
CFR part 430, subpart B, appendix N, Uniform Test Method for Measuring
the Energy Consumption of Furnaces and Boilers (``appendix N''),
respectively.\1\ The following sections discuss DOE's authority to
establish test procedures for consumer boilers and relevant background
information regarding DOE's consideration of test procedures for this
product.
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\1\ Upon the effective date of this final rule, the test
procedure for consumer boilers will be relocated to 10 CFR 430,
subpart B, appendix EE.
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A. Authority

The Energy Policy and Conservation Act, Public Law 94-163, as
amended (``EPCA''),\2\ authorizes DOE to regulate the energy efficiency
of a number of consumer products and certain industrial equipment. (42
U.S.C. 6291-6317) Title III, Part B of EPCA \3\ established the Energy
Conservation Program for Consumer Products Other Than Automobiles,
which sets forth a variety of provisions designed to improve energy
efficiency. These products include furnaces, which include consumer
boilers, the subject of this document. (42 U.S.C. 6292(a)(5))
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\2\ All references to EPCA in this document refer to the statute
as amended through the Energy Act of 2020, Public Law 116-260 (Dec.
27, 2020), which reflect the last statutory amendments that impact
Parts A and A-1 of EPCA.
\3\ For editorial reasons, upon codification in the U.S. Code,
Part B was redesignated Part A.
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The energy conservation program under EPCA consists essentially of
four parts: (1) testing, (2) labeling, (3) Federal energy conservation
standards, and (4) certification and enforcement procedures. Relevant
provisions of EPCA specifically include definitions (42 U.S.C. 6291),
test procedures (42 U.S.C. 6293), labeling provisions (42 U.S.C. 6294),
energy conservation standards (42 U.S.C. 6295), and the authority to
require information and reports from manufacturers (42 U.S.C. 6296).
The testing requirements consist of test procedures that
manufacturers of covered products must use as the basis for (1)
certifying to DOE that their products comply with the applicable energy
conservation standards adopted under EPCA (42 U.S.C. 6295(s)), and (2)
making other representations about the efficiency of those products (42
U.S.C. 6293(c)). Similarly, DOE must use these test procedures to
determine whether the products comply with any relevant standards
promulgated under EPCA. (42 U.S.C. 6295(s))
Federal energy efficiency requirements for covered products
established under EPCA generally supersede State laws and regulations
concerning energy conservation testing, labeling, and standards. (42
U.S.C. 6297) DOE may, however, grant waivers of Federal preemption for
particular State laws or regulations, in accordance with the procedures
and other provisions of EPCA. (42 U.S.C. 6297(d))
Under 42 U.S.C. 6293, EPCA sets forth the criteria and procedures
DOE must follow when prescribing or amending test procedures for
covered products. EPCA requires that any test procedures prescribed or
amended under this section shall be reasonably designed to produce test
results which measure energy efficiency, energy use, or estimated
annual operating cost of a covered product during a representative
average use cycle (as determined by the Secretary) or period of use and
shall not be unduly burdensome to conduct. (42 U.S.C. 6293(b)(3))
EPCA also requires that, at least once every 7 years, DOE evaluate
test procedures for each type of covered product, including consumer
boilers, to determine whether amended test procedures would more
accurately or fully comply with the requirements for the test
procedures to not be unduly burdensome to conduct and be reasonably
designed to produce test results that reflect energy efficiency, energy
use, and estimated operating costs during a representative average use
cycle or period of use. (42 U.S.C. 6293(b)(1)(A))
If the Secretary determines, on her own behalf or in response to a
petition by any interested person, that a test procedure should be
prescribed or amended, the Secretary shall promptly publish in the
Federal Register proposed test procedures and afford interested persons
an opportunity to present oral and written data, views, and arguments
with respect to such procedures. The comment period on a proposed rule
to amend a test procedure shall be at least 60 days and may not exceed
270 days. In prescribing or amending a test procedure, the Secretary
shall take into account such information as the Secretary determines
relevant to such procedure, including technological developments
relating to energy use or energy efficiency of the type (or class) of
covered products involved. (42 U.S.C. 6293(b)(2)) If DOE determines
that test procedure revisions are not appropriate, DOE must publish its
determination not to amend the test procedures.
In addition, EPCA requires that DOE amend its test procedures for
all covered products to integrate measures of standby mode and off mode
energy consumption into the overall energy efficiency, energy
consumption, or other energy descriptor, unless the current test
procedure already incorporates the standby mode and off mode energy
consumption, or if such integration is technically infeasible. (42
U.S.C. 6295(gg)(2)(A)) If an integrated test procedure is technically
infeasible, DOE must prescribe separate standby mode and off mode
energy use test procedures for the covered product, if a separate test
is technically feasible. (Id.) Any such amendment must consider the
most current versions of the International Electrotechnical Commission
(``IEC'') Standard 62301 \4\ and IEC Standard 62087 \5\ as applicable.
(42 U.S.C. 6295(gg)(2)(A))
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\4\ IEC 62301, Household electrical appliances--Measurement of
standby power (Edition 2.0, 2011-01).
\5\ IEC 62087, Audio, video and related equipment--Methods of
measurement for power consumption (Edition 1.0, Parts 1-6: 2015,
Part 7: 2018).
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DOE is publishing this final rule in satisfaction of the 7-year
review requirement specified in EPCA. (42 U.S.C. 6293(b)(1)(A))

B. Background

As stated, DOE's existing test procedure for consumer boilers
appears at Title 10 of CFR part 430, subpart B, appendix N, Uniform
Test Method for Measuring the Energy Consumption of Furnaces and
Boilers (``appendix N'') and is used to determine the annual fuel
utilization efficiency (``AFUE''), which is the regulatory metric for
consumer boilers.
DOE most recently updated its test procedure for consumer boilers
in a final rule published in the Federal Register on January 15, 2016
(``January 2016 Final Rule''). 81 FR 2628. The January 2016 Final Rule
amended the existing DOE test procedure for consumer boilers to improve
the consistency and accuracy of test results generated using the DOE
test procedure and to reduce test burden. In particular, the
modifications relevant to consumer boilers included: (1) clarifying the
definition of the electrical power term ``PE''; (2) adopting a smoke
stick test for determining whether minimum default

[[Page 15512]]

draft factors can be applied; (3) allowing for optional measurement of
condensate during establishment of steady-state conditions; (4)
updating references to the applicable installation and operation
(``I&O'') manual and providing clarifications for when the I&O manual
does not specify test setup; and (5) revising the AFUE reporting
precision. DOE also revised the definitions of several terms in the
test procedure and added an enforcement provision to provide a method
of test for DOE to determine compliance with the automatic means design
requirement mandated by the Energy Independence and Security Act of
2007, Public Law 110-140 (Dec. 19, 2007). 81 FR 2628, 2629-2630.
On May 15, 2020, DOE published in the Federal Register a request
for information (``May 2020 RFI'') seeking comments on the existing DOE
test procedure for consumer boilers, which incorporates by reference
ANSI/ASHRAE Standard 103-1993. 85 FR 29352. ANSI/ASHRAE 103-1993
provides test procedures for determining the AFUE of residential
central furnaces and boilers. In the May 2020 RFI, DOE requested
comments, information, and data about a number of issues, including:
(1) the test procedure's scope and definitions; (2) updates to industry
standards; (3) ambient test conditions; (4) provisions for testing
boilers with manually adjustable combustion airflow; (5) calculation of
steady-state heat loss for condensing, modulating boilers; and (6)
provisions for testing step modulating boilers. Id. at 85 FR 29354-
29357. DOE also sought comment generally on whether the current test
procedures are reasonably designed to produce results that measure
energy efficiency during a representative average use cycle or period
of use, whether any potential amendments would make the test procedure
unduly burdensome to conduct, whether existing test procedures limit a
manufacturer's ability to provide additional features, the impact of
any potential amendments on manufacturers including small businesses,
whether there are any potential issues related to emerging smart
technologies, and generally any other aspect of the test procedure for
consumer boilers. Id. at 85 FR 23957.
On March 15, 2022, DOE published in the Federal Register a notice
of proposed rulemaking (``March 2022 NOPR'') proposing to amend the
current test procedure to incorporate by reference the most current
revision to the applicable industry standard that was available at the
time, ANSI/ASHRAE 103-2017, ``Methods of Testing for Annual Fuel
Utilization Efficiency of Residential Central Furnaces and Boilers,''
as well as updating the definitions to reflect the changes in ANSI/
ASHRAE 103-2017 as compared to the version of the standard currently
incorporated by reference (i.e., ANSI/ASHRAE 103-1993). 87 FR 14624. In
addition, the March 2022 NOPR proposed to update appendix N to remove
the provisions applicable only to consumer boilers and to rename the
appendix ``Uniform Test Method for Measuring the Energy Consumption of
Furnaces.'' Correspondingly, DOE proposed to relocate the test
procedure specific to consumer boilers at 10 CFR 430 subpart B to a new
appendix, EE, ``Uniform Test Method for Measuring the Energy
Consumption of Boilers'' (``appendix EE''). Id.
On April 7, 2022, DOE held a public meeting via webinar to solicit
feedback from stakeholders on the requests for comment in the March
2022 NOPR.
DOE received comments in response to the March 2022 NOPR from the
interested parties listed in Table I.1.

Table I.1--List of Commenters With Written Submission in Response to the March 2022 NOPR
----------------------------------------------------------------------------------------------------------------
Reference in this Comment No. in
Commenter(s) final rule the docket Commenter type
----------------------------------------------------------------------------------------------------------------
American Gas Association and American Public Gas AGA and APGA.......... 25 Utility Associations.
Association.
Air-Conditioning, Heating, and Refrigeration AHRI.................. 26 Trade Association.
Institute.
A.O. Smith Corporation.......................... A.O. Smith............ 24 Manufacturer.
John Busse...................................... Busse................. 22 Individual.
Bradford White Corporation...................... BWC................... 19 Manufacturer.
Pacific Gas and Electric Company, San Diego Gas CA IOUs............... 20 Utilities.
and Electric, and Southern California Edison
(collectively, the California Investor-Owned
Utilities).
Crown Boiler Company............................ Crown................. 16 Manufacturer.
Appliance Standards Awareness Project, American Joint Advocates....... 21 Efficiency
Council for an Energy-Efficient Economy, Organizations.
Consumer Federation of America, National
Consumer Law Center Natural Resources Defense
Council, and Northwest Energy Efficiency
Alliance.
New York State Energy Research and Development NYSERDA............... 23 State Agency.
Authority.
Rheem Manufacturing Company..................... Rheem................. 18 Manufacturer.
U.S. Boiler Company............................. U.S. Boiler........... 17 Manufacturer.
----------------------------------------------------------------------------------------------------------------

A parenthetical reference at the end of a comment quotation or
paraphrase provides the location of the item in the public record.\6\
To the extent that interested parties have provided written comments
that are substantively consistent with any oral comments provided
during the April 7, 2022, public meeting, DOE cites the written
comments throughout this final rule. DOE did not identify any oral
comments provided during the webinar that are not substantively
addressed by written comments.
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\6\ The parenthetical reference provides a reference for
information located in the docket of DOE's rulemaking to develop
test procedures for consumer boilers. (Docket No. EERE-2019-BT-TP-
0037, maintained at <a href="http://www.regulations.gov">www.regulations.gov</a>.) The references are
arranged as follows: (commenter name, comment docket ID number, page
of that document).
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II. Synopsis of the Final Rule

In this final rule, DOE updates appendix N to remove the provisions
applicable only to consumer boilers and to rename the appendix
``Uniform Test Method for Measuring the Energy Consumption of
Furnaces.'' Correspondingly, this final rule establishes a new test
procedure specific to consumer boilers in a new appendix EE. In
appendix EE, DOE includes all provisions currently included in appendix
N relevant to consumer boilers, with the following modifications:
(1) Incorporate by reference the current version of the applicable
industry standard, ANSI/ASHRAE 103-2017, ``Methods of Testing for
Annual Fuel Utilization Efficiency of

[[Page 15513]]

Residential Central Furnaces and Boilers,'' which includes several
updates to the test method.
(2) Incorporate by reference the current version of ASTM Standard
D2156-09 (Reapproved 2018), ``Standard Test Method for Smoke Density in
Flue Gases from Burning Distillate Fuels.''
(3) Incorporate by reference ANSI/ASHRAE 41.6-2014, ``Standard
Method for Humidity Measurement.''
(4) Update the definitions to reflect the changes in ANSI/ASHRAE
103-2017 as compared to ANSI/ASHRAE 103-1993.
(5) Provide corrections to erroneous calculations and add
clarifications to test conditions and setup requirements.
DOE is also removing the definition of ``outdoor furnace or
boiler'' from 10 CFR 430.2.
The adopted amendments are summarized in Table II.1 compared to the
test procedure provision prior to the amendment, as well as the reason
for the adopted change.

Table II.1--Summary of Changes in the Amended Test Procedure
------------------------------------------------------------------------
DOE test procedure prior to
amendment Amended test procedure Attribution
------------------------------------------------------------------------
Incorporated by reference Incorporates by Harmonization
industry standard ANSI/ASHRAE reference ANSI/ASHRAE with industry
103-1993. 103-2017 in the new standard
appendix EE. update.
Incorporated by reference the Incorporates by Harmonization
procedure for adjusting oil- reference the with industry
fired burner by referencing procedure for standard
industry standard ASTM D2156- adjusting oil-fired update.
09 (Reapproved 2013). burner by referencing
industry standard
ASTM D2156-09
(Reapproved 2018) in
the new appendix EE.
Limited the maximum relative Incorporates by Referenced by
humidity of the test room reference ANSI/ASHRAE industry
during certain tests but did 41.6-2014 standard ANSI/
not provide specific instructions for ASHRAE 103-
instructions for how to measuring relative 2017, which is
measure relative humidity. humidity of the test being
room in the new incorporated by
appendix EE. reference in
this final
rule.
Included a definition for Removes the definition Unused
``outdoor furnace or boiler'' for ``outdoor furnace definition.
at 10 CFR 430.2. or boiler''.
Included an undefined term, Adds a definition for Increase clarity
``standard cubic foot of ``standard cubic foot for testing
gas''. of gas'' in new conditions.
appendix EE.
Defined ``control'' and Adopts the definitions Harmonization
``isolated combustion for the terms with industry
system'' in appendix N. ``control'' and standard
``isolated combustion update.
system'' from ASHRAE
103-2017 in new
appendix EE.
Referenced calculations in Includes an amended Correction.
ANSI/ASHRAE 103-1993 which calculation for
yielded a circular reference balance-point
when calculating the steady- temperature (TC)
state efficiency for which resolves the
condensing modulating boilers. circular reference in
new appendix EE.
Referenced Table 9 in ANSI/ References Table 7 of Harmonization
ASHRAE 103-1993, which ANSI/ASHRAE 103-2017 with industry
assigned fixed values for the in the new appendix standard
average on-time and off-time EE, which uses update.
per cycle for two-stage and calculations for
modulating boilers. determining the
average on-time and
off-time per cycle
for two-stage and
modulating boilers.
Specified cycle times (tON and Provides additional Clarification to
tOFF) to a fraction of a specification in reduce test
second through reference to appendix EE to burden.
ANSI/ASHRAE 103-1993 Table 9. require that
calculated cycle
timings shall be
rounded to the
nearest second.
Calculated oversize factor Adopts the ANSI/ASHRAE Harmonization
from a lookup table based on 103-2017 methodology with industry
design heating requirement of assigning a standard
(``DHR'') in ANSI/ASHRAE 103- constant value of update.
1993. 0.70 to [alpha] to
represent the
national average
oversize factor in
appendix EE.
Used a purge time limit of 5 Applies the 30-second Harmonization
seconds to determine whether limit in appendix EE with industry
heat-up and cool-down tests for determining when standard
may be optionally omitted, the heat-up and cool- update.
whereas a purge time limit of down tests may be
30 seconds was used to optionally omitted.
determine whether a post-
purge (tP) of 0 seconds could
be assigned in calculations.
Limited the maximum value of Removes the maximum Harmonization
post-purge (tP) to 180 value of 180 seconds with industry
seconds if a purge time of in appendix EE and standard
greater than 3 minutes was requires an update.
observed. additional
temperature
measurement to be
taken if the post-
purge is greater than
3 minutes.
Referenced calculations for Specifies the correct Correction.
off-cycle infiltration losses calculation for off-
in ANSI/ASHRAE 103-1993 which cycle infiltration
had a typographical error losses through
where the conversion from reference to ANSI/
minutes to hours was ASHRAE 103-2017 and
performed incorrectly. corrects minutes to
hours conversion
error in new appendix
EE.
Provided inconsistent unit Corrects the Correction.
conversion factor from watts conversion factor
(``W'') to British thermal from W to Btu/h to
units per hour (``Btu/h''), 3.412 throughout new
using values of 3.412 or appendix EE.
3.413.
Required the use of a gas Requires the use of a Clarification to
having a specific gravity as gas having a specific reduce test
shown in Table 1 of ANSI/ gravity burden.
ASHRAE 103-1993. ``approximate'' to
what is shown in
Table 1 of ANSI/
ASHRAE 103-2017 in
the new appendix EE.
Referenced incorrect sections Revises 10 CFR Correction.
of appendix N test procedure 430.23(n)(1) to
regarding average annual update references
auxiliary electrical regarding average
consumption determination annual auxiliary
provisions at 10 CFR electrical
430.23(n)(1). consumption to the
correct sections of
appendix N and the
new appendix EE.
Referenced values in ANSI/ References values in Harmonization
ASHRAE 103-1993 for ANSI/ASHRAE 103-2017 with industry
determining national average for determining standard
burner operating hours national average BOH, update.
(``BOH''), average annual average annual EF,
fuel energy consumption and average annual
(``EF''), and average annual EAE in the new
auxiliary electrical energy appendix EE.
consumption (``EAE'').

[[Page 15514]]

Included instructions for the Includes units of Correction.
setup of boilers with draft measure for R-value
hoods or draft diverters in the new appendix
which specified a minimum R- EE.
value for insulation but did
not specify the units of
measure for R-value.
------------------------------------------------------------------------

DOE has determined that the amendments described in section III of
this document and adopted in this final rule will not substantively
impact the measured efficiency of consumer boilers or require retesting
or recertification solely as a result of DOE's adoption of the
amendments to the test procedures. Additionally, DOE has determined
that the amendments will not increase the cost of testing. Discussion
of DOE's actions is addressed in detail in section III of this
document.
The effective date for the amended test procedures adopted in this
final rule is 30 days after publication of this document in the Federal
Register. Representations of energy use or energy efficiency must be
based on testing in accordance with the amended test procedures
beginning 180 days after the publication of this final rule.

III. Discussion

The subsequent sections of this final rule discuss specific topics
raised in this rulemaking, including comments DOE received in response
to the March 2022 NOPR. These topics include: scope of applicability of
the test procedure, definitions in the test procedure, the AFUE metric,
updates to industry standards, clarifications and corrections to the
current test procedure, and test conditions.
In addition, DOE received comments relating to the general
processes by which DOE amends test procedures and energy conservation
standards for covered products and equipment.
BWC urged DOE to consider the cumulative regulatory burden placed
on manufacturers that produce several different types of regulated
products for which there are simultaneous rulemakings. BWC noted that
additional burdens on manufacturers include changes to ENERGY STAR
specifications; the Securities and Exchange Commission's proposed rule
to enhance and standardize climate-related disclosures; updated state
and local codes; demand-response requirements for electric water
heaters in Western States; lower nitrogen oxides (NO<INF>X</INF>)
emissions proposals in the State of California; proposed amendments to
California Proposition 65; and extended producer responsibility
legislation recently enacted in both Maine and Oregon. (BWC, No. 19 at
p. 4-5)
In response, DOE notes that cumulative regulatory burden on
manufacturers is assessed as part of energy conservation standards
rulemakings. The amendments to the consumer boilers test procedure, as
promulgated by this final rule, are not expected to add burden to
manufacturers because the amendments do not substantially impact
efficiency ratings or alter the type of equipment necessary to perform
testing. Test costs and burden are discussed in section III.K of this
document.
AGA and APGA commented that DOE should implement the
recommendations from the recent National Academies of Sciences,
Engineering, and Medicine report (``NASEM report'') \7\ into all of its
appliance rulemakings for test procedures or energy conservation
standards. AGA and APGA reiterated recommendations pertaining to
analyses that DOE conducts in order to determine whether potential new
or amended energy conservation standards are technologically feasible
and economically justified. (AGA and APGA, No. 25, p. 3) For example,
AGA and APGA highlighted the NASEM report's recommendations that DOE
pay greater attention to the justification for its standards, expand
the Cost Analysis segment of the Engineering Analysis for its rules,
put greater weight on ex post and market-based evidence markups, place
greater emphasis on providing an argument for the plausibility and
magnitude of any market failure related to the energy efficiency gap,
and give greater attention to a broader set of potential market
failures on the supply side. Id.
---------------------------------------------------------------------------

\7\ Although not specified, DOE interprets this comment to refer
to the National Academies of Science, Engineering, and Medicine 2021
report entitled ``Review of Methods Used by the U.S. Department of
Energy in Setting Appliance and Equipment Standards.'' Copies of the
report are available at <a href="http://nap.nationalacademies.org/catalog/25992/review-of-methods-used-by-the-us-department-of-energy-in-setting-appliance-and-equipment-standards">nap.nationalacademies.org/catalog/25992/review-of-methods-used-by-the-us-department-of-energy-in-setting-appliance-and-equipment-standards</a>.
---------------------------------------------------------------------------

Given that this is a test procedure rulemaking for which DOE must
meet specific statutory criteria as outlined in 42 U.S.C. 6293(b)(3),
the recommendations in the NASEM report which pertain specifically to
the processes by which DOE analyzes energy conservation standards are
misplaced. DOE will consider this comment in a separate rulemaking
considering all product categories.

A. Scope of Applicability

As discussed, in the context of ``covered products,'' EPCA includes
boilers in the definition of ``furnace.'' (42 U.S.C. 6291(23)) EPCA
defines the term ``furnace'' to mean a product which utilizes only
single-phase electric current, or single-phase electric current or DC
current in conjunction with natural gas, propane, or home heating oil,
and which: (1) is designed to be the principal heating source for the
living space of a residence; (2) is not contained within the same
cabinet with a central air conditioner whose rated cooling capacity is
above 65,000 Btu/h; (3) is an electric central furnace, electric
boiler, forced-air central furnace, gravity central furnace, or low
pressure steam or hot water boiler; and (4) has a heat input rate of
less than 300,000 Btu/h for electric boilers and low pressure steam or
hot water boilers and less than 225,000 Btu/h for forced-air central
furnaces, gravity central furnaces, and electric central furnaces. Id.
DOE has codified this definition in its regulations at 10 CFR 430.2.
DOE defines ``electric boiler'' as an electrically powered furnace
designed to supply low pressure steam or hot water for space heating
application. A low pressure steam boiler operates at or below 15 pounds
per square inch gauge (``psig'') steam pressure; a hot water boiler
operates at or below 160 psig water pressure and 250 degrees Fahrenheit
([deg]F) water temperature. 10 CFR 430.2.
DOE defines ``low pressure steam or hot water boiler'' as an
electric, gas or oil burning furnace designed to supply low pressure
steam or hot water for space heating application. 10 CFR 430.2. As with
an electric boiler, a low pressure steam boiler operates at or below 15
pounds psig steam pressure; a hot water boiler operates at or below 160
psig water pressure and 250 [deg]F water temperature. Id.
The scope of the test procedure for consumer boilers is currently
specified

[[Page 15515]]

in section 1 of appendix N, which references section 2 of ANSI/ASHRAE
103-1993. In relevant part, section 2 of ANSI/ASHRAE 103-1993 states
that the industry test standard applies to boilers \8\ with inputs less
than 300,000 Btu/h; having gas, oil, or electric input; and intended
for use in residential applications. Further, ANSI/ASHRAE 103-1993
applies to equipment that utilizes single-phase electric current or
low-voltage DC current.
---------------------------------------------------------------------------

\8\ ASHRAE 103-1993 defines a boiler as ``a self-contained fuel-
burning or electrically heated appliance for supplying low pressure
steam or hot water for space heating application.'' This definition
covers electric boilers and low pressure steam or hot water boilers
as those terms are defined by DOE at 10 CFR 430.2.
---------------------------------------------------------------------------

DOE is not changing the scope of products covered by its consumer
boiler test procedure in this final rule. The following sections
discuss specific types of boilers that DOE addressed in the March 2022
NOPR with respect to whether such products are covered by the scope of
DOE's test procedure.
1. Combination Space/Water Heating Boilers
Some consumer boilers are capable of providing both space heating
and domestic hot water heating, and are often referred to as
``combination'' boilers. In the March 2022 NOPR, DOE responded to
comments from the Northwest Energy Efficiency Alliance (``NEEA'') and
Rheem recommending that DOE consider developing a separate test
procedure for combination space and domestic hot water boilers. 87 FR
14622, 14626-14627. While DOE did not propose a specific definition for
combination space and water heating boilers in the NOPR, DOE noted
that, to the extent that a combination space and water heating product
meets the definition of electric boiler or low pressure steam or hot
water boiler, it is subject to the test procedure at appendix N and
energy conservation standards for consumer boilers at 10 CFR
430.32(e)(2), and must be tested and rated accordingly. 87 FR 14622,
14625-14626. DOE also stated that it is unaware of any design
characteristics of combination space and water heating products that
would prevent their testing according to appendix N. Id.
DOE did not receive any comments in response to the March 2022 NOPR
with regard to combination space and heating water boilers. In this
final rule, DOE reiterates its statements presented in the March 2022
NOPR with respect to combination boilers. To the extent that a
combination space and water heating product meets the definition of
electric boiler or low pressure steam or hot water boiler, it is
subject to the test procedure at appendix N (or, as of the effective
date of this final rule, appendix EE) and energy conservation standards
for consumer boilers at 10 CFR 430.32(e)(2), and must be tested and
rated accordingly.
2. Heat Pump Boilers
In the March 2022 NOPR, DOE discussed comments received in response
to the May 2021 RFI with regard to hydronic air-to-water and water-to-
water heat pumps. DOE tentatively determined that air-to-water and
water-to-water heat pumps meet the definitional criteria to be
classified as a consumer boiler. 87 FR 14622, 14625. DOE noted that
these products utilize only single-phase electric current, are designed
to be the principal heating source for the living space of a residence,
are not contained within the same cabinet with a central air
conditioner whose rated cooling capacity is above 65,000 Btu/h, meet
the definition of an electric boiler,\9\ and have a heat input rate of
less than 300,000 Btu/h (i.e., the requirement for electric boilers).
As such, they meet the criteria of ``furnace'' as defined in 10 CFR
430.2. Id. at 87 FR 14625-14626.
---------------------------------------------------------------------------

\9\ ``Electric boiler'' means an electrically powered furnace
designed to supply low pressure steam or hot water for space heating
application. A low pressure steam boiler operates at or below 15
psig steam pressure; a hot water boiler operates at or below 160
psig water pressure and 250 [deg]F water temperature. 10 CFR 430.2.
---------------------------------------------------------------------------

In the March 2022 NOPR, DOE also tentatively determined that the
test procedure in appendix N does not address such products and would
not provide a rated value that is representative of the performance of
these products. Id. at 14626. In particular, DOE noted that the AFUE
metric for electric boilers in ANSI/ASHRAE 103-1993 is calculated as
100 percent minus jacket loss,\10\ which provides a representative
measure of efficiency for electric boilers using electric resistance
technology, for which an efficiency value of 100 percent (the ratio of
heat output to energy input) is the maximum upper limit that
technically could be achieved. DOE tentatively concluded that the AFUE
metric would not provide a representative or meaningful measure of
efficiency for a boiler with a heat pump supplying the heat input,
because heat pump efficiency (in terms of heat output to energy input)
typically exceeds 100 percent, and the AFUE metric does not allow for
ratings greater than 100 percent for electric boilers. Id.
---------------------------------------------------------------------------

\10\ The term ``jacket loss'' is used by industry to mean the
transfer of heat from the outer surface (i.e., jacket) of a boiler
to the ambient air surrounding the boiler.
---------------------------------------------------------------------------

Based on these considerations, DOE tentatively determined that
hydronic air-to-water and water-to-water heat pumps are consumer
boilers under EPCA, but that due to the lack of a Federal test
procedure, such products are not subject to the current performance
standards at 10 CFR 430.32(e). Id.
In response to the March 2022 NOPR, Crown and U.S. Boiler \11\
stated that hydronic heat pumps should not be classified as boilers
under EPCA because hydronic heat pumps cannot deliver water at the same
temperatures and heating capacities as traditional boilers. Crown and
U.S. Boiler further commented that it is unclear whether hydronic heat
pumps are ``designed to be the principal heating source for a living
space of a residence'' (a requirement to meet the definition of a
furnace at 10 CFR 430.2) because these products are mostly incapable of
reaching above 150 [deg]F on a design day, whereas traditional boilers
are designed to deliver water at a temperature of 180 [deg]F or higher.
Crown and U.S. Boiler also stated that gas, oil, and electric
resistance boilers are capable of heating any hot water or steam
heating system throughout the entire heating season, whereas hydronic
heat pumps do not have such capabilities. Crown and U.S. Boiler stated
that heat pumps and boilers provide different consumer utility, and
suggested that presenting heat pumps to consumers as ``boilers'' could
create confusion with regard to the different capabilities of each.
(Crown, No. 16 at p. 1-2; -U.S. Boiler, No. 17 at p. 1-2)
---------------------------------------------------------------------------

\11\ DOE notes that both Crown and U.S. Boiler's comments stated
that the companies are subsidiaries of Burnham Holdings, Inc.
(``BHI''). The comments submitted by Crown and U.S. Boiler in
response to the March 2022 NOPR were identical in content.
---------------------------------------------------------------------------

AHRI and AGA and APGA commented that hydronic heat pumps cannot
currently provide the same functionality as boilers for high
temperature installations as they are unable to provide water at or
over 210 [deg]F, and that this lack of utility should disqualify these
products from being considered in the boiler test procedure. (AHRI, No.
26 at p. 2; AGA and APGA, No. 25 at p. 2)
BWC disagreed with DOE's tentative determination that air-to-water
and water-to-water heat pumps should be defined as consumer boilers.
BWC stated that heat pump products and consumer boilers have pronounced
differences that should prevent them from being defined as the same
product.

[[Page 15516]]

BWC noted that boilers and heat pumps \12\ are already separate product
categories on DOE's website and certified separately through DOE's
Compliance Certification Management System. BWC also stated that
hydronic heat pumps are rated to Coefficient of Performance (``COP'')
rather than AFUE (for boilers), and that the unique technologies
utilized by both product types necessitate different methods for
testing and rating them. BWC further stated that consumer boilers are
designed exclusively to provide a heating utility, whereas hydronic
heat pumps can be used to provide both space heating and cooling. (BWC,
No. 19 at p. 2-3)
---------------------------------------------------------------------------

\12\ DOE understands BWC is referring to central air
conditioning and heat pump units.
---------------------------------------------------------------------------

Rheem supported DOE's tentative determination that hydronic air-to-
water and water-to-water heat pumps are consumer boilers under EPCA.
Rheem stated that although these products may not necessarily be able
to achieve the same maximum temperatures as conventional boilers
(without electric resistance or gas backup), hydronic heat pump boilers
can still provide adequate space heating in many applications. Rheem
recommended that DOE either add procedures to test hydronic heat pumps
in this consumer boiler test procedure rulemaking or initiate a
separate test procedure rulemaking. Rheem asserted that these products
perform the same function as other types of boilers and should be
tested and rated in a similar manner, and that DOE could use the
current AFUE test procedure as a guide to produce an ``AFUE metric''
for hydronic heat pumps that combines the various energy use modes and
input rate conditions with test conditions and operating assumptions
that are representative of hydronic heat pumps. Rheem stated that any
differences in ability to meet consumer heating demands should be
considered in the development of energy conservation standards, as
opposed to the test procedure. (Rheem, No. 18 at p. 2)
NYSERDA agreed with DOE's tentative determination that air-to-water
and water-to-water heat pumps should be considered boilers under EPCA.
NYSERDA recommended that DOE develop a test procedure for these heat
pumps and combination space heating and water heating products. NYSERDA
asserted that the adoption of these test procedures will also enable
future standards revisions to adopt more efficient heat pump levels of
performance. (NYSERDA, No. 23 at p. 5-6)
In consideration of the comments received on this issue, as well as
further consideration of the discussion presented in the March 2022
NOPR, DOE has concluded that hydronic air-to-water and water-to-water
heat pumps meet the definitional criteria to be classified as a
consumer boiler. In particular, as noted initially in the March 2022
NOPR, DOE concludes that these products utilize only single-phase
electric current, are designed to be the principal heating source for
the living space of a residence, and are not contained within the same
cabinet with a central air conditioner whose rated cooling capacity is
above 65,000 Btu/h. In addition, electric heat pump boilers meet the
definition of an electric boiler; and gas-fired heat pump boilers meet
the definition of a low pressure steam or hot water boiler and have a
heat input rate of less than 300,000 Btu/h (i.e., the requirement for
electric boilers and low pressure steam or hot water boilers). As such,
these products meet the criteria of ``furnace'' as defined in 10 CFR
430.2.
With respect to comments from Crown, U.S. Boiler, AHRI, and AGA and
APGA suggesting hydronic air-to-water heat pumps and water-to-water
heat pumps should be excluded from the definition because they cannot
provide the same maximum water temperature as non-heat pump hydronic
systems, DOE notes that neither EPCA nor DOE's definitions at 10 CFR
430.2 provide a minimum water temperature requirement. In addition, in
response to comments that hydronic heat pumps serve different
applications than boilers, DOE notes that hydronic heat pumps are
marketed as providing the principal heating source for a residence, and
nothing in EPCA's or DOE's definition would exclude them based on their
ability to also provide cooling.
DOE recognizes that hydronic heat pump products differ
significantly from non-heat pump boilers, and that the current test
procedure for consumer boilers (as well as the amended test procedure
established by this final rule) would not provide test results that are
representative of the energy use or energy efficiency of an air-to-
water or water-to-water heat pump product. Because of these differences
and uncertainty regarding the most representative approach to testing
these products, DOE is not establishing separate test procedures for
hydronic heat pump products in this final rule. Although air-to-water
and water-to-water heat pump products meet all the definitional
criteria to be considered a consumer boiler, the Department requires
more information in order to determine a representative approach for
testing these products. Further consideration of an appropriate test
procedure for such products would be provided in a separate test
procedure rulemaking. Section III.C of this document further discusses
the applicability of the AFUE metric to hydronic heat pump products.

B. Definitions

In addition to the overarching definition of ``furnace'' (which
includes boilers) and the associated definitions for ``electric
boiler'' and ``low pressure steam or hot water boiler'' presented in
section III.A of this document, DOE also has defined ``outdoor
boilers'' and ``weatherized warm air boilers'' at 10 CFR 430.2 as
follows:
<bullet> ``Outdoor furnace or boiler'' is a furnace or boiler
normally intended for installation out-of-doors or in an unheated space
(such as an attic or a crawl space).
<bullet> ``Weatherized warm air furnace or boiler'' means a furnace
or boiler designed for installation outdoors, approved for resistance
to wind, rain, and snow, and supplied with its own venting system.
In the March 2022 NOPR, DOE proposed to remove the definition of
``outdoor furnace or boiler'' from its regulations, noting that the
definition is not used for the energy conservation standards for
boilers at 10 CFR 430.32(e)(2)(iii), nor for applying the test
procedure.\13\ 87 FR 14622, 14626-14627. DOE sought comment on its
proposal to remove the definition of ``outdoor furnace or boiler'' from
its regulations and whether removing the definition for ``outdoor
furnace or boiler'' would impact the application of the test procedure
or energy conservation standards for any such products.
---------------------------------------------------------------------------

\13\ Specifically, with respect to the test procedure, DOE noted
that different jacket loss factors are applied based on whether a
boiler is intended to be installed indoors, outdoors, or as an
isolated combustion system. The heating seasonal efficiency
(Effy<INF>HS</INF>) calculation, which is an element of AFUE, is
based on the assumption that all weatherized boilers are located
outdoors (see section 10.1 of appendix N). Appendix N does not
specify a separate jacket loss assumption for outdoor furnaces or
boilers.
---------------------------------------------------------------------------

Rheem and BWC supported DOE's proposal to remove the definition of
``outdoor furnace or boiler'' from 10 CFR 430.2. (Rheem, No. 18 at p.
2; BWC, No. 19 at p. 1) A.O. Smith stated that removal of this
definition from the DOE regulations would not have a negative impact on
the application of the test procedure or energy conservation standards.
(A.O. Smith, No. 24 at p. 2) AHRI and AGA and APGA also supported
removing the definition and

[[Page 15517]]

stated that the removal would add clarity and consistency to the test
procedure. (AHRI, No. 26 at p. 2; AGA and APGA, No. 25 at p. 2)
For the reasons discussed in the March 2022 NOPR, and in
consideration of these comments, in this final rule DOE finalizes its
proposal to remove the definition of ``outdoor furnace or boiler'' from
10 CFR 430.2.
In the March 2022 NOPR, DOE proposed to incorporate by reference
ANSI/ASHRAE 103-2017, including the definitions included therein. 87 FR
14622, 14627. DOE noted that ANSI/ASHRAE 103-2017 includes definitions
for ``air intake terminal,'' ``control,'' and ``isolated combustion
system'' that are not in ANSI/ASHRAE 103-1993. Id. The definitions for
``control'' and ``isolated combustion system'' in ANSI/ASHRAE 103-2017
are almost identical to the definitions for those terms currently
defined in sections 2.3 and 2.7 of appendix N, respectively. Therefore,
DOE proposed to remove the definitions for ``control'' and ``isolated
combustion system'' from DOE's consumer boiler test procedure, as they
would be redundant with the definitions incorporated by reference
through ANSI/ASHRAE 103-2017, if the proposal to incorporate by
reference ANSI/ASHRAE 103-2017 were finalized. Id.
Rheem, The CA IOUs, A.O. Smith, AHRI, and AGA and APGA supported
incorporating by reference the definitions in ANSI/ASHRAE 103-2017 and
removing the separate definitions for ``control'' and ``isolated
combustions system'' from DOE's test procedure. (Rheem, No. 18 at p. 3;
CA IOUs, No. 20 at p. 1; A.O. Smith, No. 24 at p. 3; AHRI, No. 26 at p.
2; AGA and APGA, No. 25 at p. 2)
For the reasons discussed in the March 2022 NOPR, and in
consideration of these comments, DOE is removing the separate
definitions for ``control'' and ``isolated combustion system'' from the
consumer boiler test procedure, as proposed in the March 2022 NOPR. The
definitions for these products are instead provided through DOE's
incorporation by reference of ANSI/ASHRAE 103-2017, as discussed
further in section III.D.1 of this final rule.
In response to the March 2022 NOPR, Busse suggested that DOE add a
definition for ``standard cubic unit of gas'' as follows:
``Standard cubic foot of gas: The amount of gas that would occupy 1
cubic foot when at a temperature of 60 [deg]F, if saturated with water
vapor, and under a pressure equivalent to that of 30 inches mercury
column.'' (Busse, No. 22 at p. 9)
Busse stated that a definition of standard cubic foot of gas is
necessary to comply with the conditions specified in section 7.1 of
appendix N, Fuel Supply.\14\ Busse further stated that the suggested
definition would be consistent with industry standards NFPA 54/ANSI
Z223.1, National Fuel Gas Code, and CSA 4.9/ANSI Z21.13, Gas-Fired Low
Pressure Steam and Hot Water Boilers and asserted that manufacturers
are familiar with this definition when conducting performance testing.
Busse noted that the difference between a saturated ``wet'' and
unsaturated ``dry'' cubic foot of gas is 1.73 percent at standard
temperature and pressure. Busse also recommended that DOE modify the
language of section 7.3 of appendix N, Gas Burner, to replace ``gas
characteristics at a temperature of 60 [deg]F and atmospheric pressure
of 30 in of Hg'' with reference to this new definition, i.e., ``gas
characteristics to standard cubic foot of gas, as defined in section 2
of this appendix,'' in specifying the conditions needed to correct the
burner input rate.\15\ (Busse, No. 22 at p. 9-10)
---------------------------------------------------------------------------

\14\ Section 7.1 of appendix N requires determining the actual
higher heating value in Btu per standard cubic foot for the gas to
be used in the test within an error no greater than 1 percent.
\15\ Busse also commented that, with respect to the current
instruction to ``Correct the burner input rate to reflect gas
characteristics,'' technically the Ideal Gas Laws can be applied
only to the volume of gas consumed and the higher heating value, and
not to the burner input rate.
---------------------------------------------------------------------------

In response, DOE notes that as proposed in the March 2022 NOPR,
section 7.3 of appendix EE would require that the burner input rate be
corrected to reflect gas characteristics at a temperature of 60 [deg]F
and atmospheric pressure of 30 in of Hg when adjusting the burner input
rate. Therefore, an additional definition for a standard cubic foot of
gas for the purpose of referencing it in sections 7.1 and 7.3 (which is
consistent with the language in section 9.1.2.2.1 of both ANSI/ASHRAE
103-1993 and ANSI/ASHRAE 103-2017) would be unnecessary; however, it
may be useful for clarification.
As such, DOE is adding a definition for a ``standard cubic foot of
gas'' to section 2 of appendix EE to specify the temperature and
pressure for a standard cubic foot of gas.

C. Metric

As discussed, the energy conservation standards for consumer
boilers rely on the AFUE metric. 10 CFR 430.32(e)(2). For gas-fired and
oil-fired boilers, AFUE accounts for fossil fuel consumption in active,
standby, and off modes, but does not include electrical energy
consumption. For electric boilers, AFUE accounts for electrical energy
consumption in active mode. EPCA defines the term ``annual fuel
utilization efficiency,'' in part, as the efficiency descriptor for
furnaces and boilers. (42 U.S.C. 6291(20)) In addition, DOE has
established separate metrics and energy conservation standards for
power consumption during standby mode and off mode (P<INF>W,SB</INF>
and P<INF>W,OFF</INF>, respectively). 10 CFR 430.32(e)(2)(iii)(B).
AFUE is defined by ASHRAE 103 (both the 1993 and 2017 versions) as
the ratio of annual output energy to annual input energy, which
includes any non-heating-season pilot input loss but does not include
electric energy for gas- or oil-fired furnaces or boilers. For gas- and
oil-fired boilers, the AFUE test generally consists of steady-state,
cool down, and heat up tests, during which various measurements are
taken (e.g., flue gas temperature, concentration of CO<INF>2</INF> in
the flue gas). (See sections 9.1, 9.5, and 9.6 of both ANSI/ASHRAE 103-
1993 and ANSI/ASHRAE 103-2017.) For condensing boilers, condensate
collection tests during steady-state and cyclic operation are also
specified. (See sections 9.2 and 9.8 of both ANSI/ASHRAE 103-1993 and
ANSI/ASHRAE 103-2017.) The test measurements are used in conjunction
with certain assumptions to calculate the AFUE. (See section 11 of both
ANSI/ASHRAE 103-1993 and ANSI/ASHRAE 103-2017.)
In the March 2022 NOPR, after tentatively concluding that hydronic
heat pumps meet the definitional criteria to be considered a consumer
boiler but that the existing test procedure does not apply to them, DOE
sought comment on whether any other industry test methods exist for
determining the heating efficiency of air-to-water or water-to-water
heat pumps. DOE sought comment specifically on AHRI 550/590, and
whether it would be appropriate for adoption as a Federal test
procedure for such products, and if so, whether modifications could be
made to result in an AFUE rating. 87 FR 14622, 14626.
NYSERDA urged DOE to adopt appropriate, industry-recognized test
procedures to support informed consumer choice between electric
resistance and heat pump products. (NYSERDA, No. 23 at p. 5-6)
BWC stated that it believes DOE has correctly identified the
appropriate test procedures for both consumer boilers and hydronic heat
pumps at this time, with those procedures being ASHRAE 103-2017 and
AHRI 550/590 respectively. (BWC, No. 19 at p 2-3)

[[Page 15518]]

Rheem identified AHRI 550/590 as an industry test method to determine
maximum and part-load COP values but noted this test method would have
to be modified to account for standby mode and off mode energy use as
well as to produce an AFUE metric. (Rheem, No. 18 at p. 2)
The Joint Advocates stated that while AHRI 550/590 is appropriate
for evaluating the performance of consumer air-to-water heat pumps, it
is only applicable for water-to-water heat pumps with a capacity
greater or equal to 135,000 Btu/h. The Joint Advocates stated that
ASHRAE/ANSI/AHRI/ISO Standard 13256-2 is more appropriate for consumer
water-to-water heat pumps and referred to international standards EN
14511 and EN 14825 as starting points. The Joint Advocates asserted
that a seasonal performance rating analogous to AFUE could be
established and encouraged DOE to establish these procedures in a
timely manner so that consumers have access to efficiency ratings based
on a standardized test procedure. Finally, the Joint Advocates stated
that based on 2015 Residential Energy Consumption Survey (``RECS'')
data, hydronic systems are the main heating means in 8 percent of U.S.
homes overall and the main heating means for 28 percent of households
in the Northeastern United States. (Joint Advocates, No. 21 at p. 1-2)
A.O. Smith stated that ISO Standard 13256-2 would be the most
appropriate test method for water source heat pump water heaters
intended to be used as consumer hot water boilers, and that AHRI
Standard 550/590 would be the most appropriate test method for air
source heat pump water heaters intended to be used as consumer hot
water boilers. Pertaining specifically to AHRI 550/590, A.O. Smith
stated that the test procedure to measure COP has fundamental
differences than the test procedure to measure AFUE, and that there is
no means of deriving an AFUE value from the COP measurement. In
addition, A.O. Smith claimed that if the limit for consumer heat pump
water ``boilers'' is defined by an input rate of less than 300,000 Btu/
h, then the output for these products will include products with
heating capacities up to 900,000 Btu/h, which would be outside the
scope of a consumer boiler. A.O. Smith recommended that DOE review the
referenced performance standards, as they define the heating capacity
based on the heat moved into the water being heated, whereas DOE's
definition is based on the energy being consumed by the boiler. (A.O.
Smith, No. 24 at p. 2)
As stated in section III.A.2 of this document, DOE has concluded
that hydronic heat pumps meet the definitional criteria to be covered
as a consumer boiler under EPCA's statutory definition at 42 U.S.C.
6291(23) and DOE's regulatory definition at 10 CFR 430.2. However, DOE
is not adopting a separate test procedure or metric for hydronic heat
pumps in this final rule because the Department requires more
information in order to determine a representative approach for testing
these products. DOE will continue to consider the appropriate metric to
assess the efficiency of such products, and any proposed test procedure
would be addressed in a separate test procedure rulemaking in the
future.

D. Updates to Industry Standards

The DOE test method for consumer boilers references several
industry standards, including ANSI/ASHRAE 103 for various testing
requirements pertaining to determination of AFUE, certain sections of
IEC 62301 (Second Edition) for determining the electrical standby mode
and off mode energy consumption, and ASTM D2156-09 (Reapproved 2013)
for adjusting oil burners. The following sections discuss DOE's
amendments pertaining to the incorporation by reference of these
industry standards.
1. ANSI/ASHRAE 103
As discussed, ANSI/ASHRAE 103-1993 is referenced throughout
appendix N for various testing requirements pertaining to determination
of the AFUE of consumer boilers. ANSI/ASHRAE 103-1993 provides
procedures for determining the AFUE of consumer boilers (and furnaces).
As mentioned previously, ANSI/ASHRAE 103-1993 has been updated multiple
times. In the rulemaking that culminated in the January 2016 Final
Rule, DOE initially proposed to incorporate by reference the most
recent version of ANSI/ASHRAE 103 available at the time (i.e., ANSI/
ASHRAE 103-2007), but ultimately declined to adopt the proposal in the
final rule based on concerns about the impact this change would have on
AFUE ratings of products distributed in commerce at that time. 81 FR
2628, 2632-2633 (Jan. 15, 2016). DOE stated that further evaluation was
needed to determine the potential impacts of ANSI/ASHRAE 103-2007 on
the measured AFUE of boilers. Id. DOE theorized that ANSI/ASHRAE 103-
2007 might better account for the operation of two-stage and modulating
products and stated that DOE may further investigate adopting it or a
successor test procedure in the future. Id.
After the January 2016 Final Rule, ANSI/ASHRAE 103 was again
updated in 2017 (i.e., ANSI/ASHRAE 103-2017). In the May 2020 RFI, DOE
identified several substantive differences between ANSI/ASHRAE 103-1993
and ANSI/ASHRAE 103-2017 that pertain to consumer boilers and requested
further comment on the differences between ANSI/ASHRAE 103-1993 and
ANSI/ASHRAE 103-2017. 85 FR 29352, 29355.
In the March 2022 NOPR, DOE discussed additional differences
between ANSI/ASHRAE 103-1993 and ANSI/ASHRAE 103-2017 raised by
commenters in response to the May 2020 RFI. 87 FR 14622, 14628-14631.
The differences between the two versions of the standard are discussed
in detail in sections III.D.1.a through III.D.1.f of this document.
After considering the differences between the standards and the
potential impact, DOE proposed to incorporate by reference the most
recent version (at the time) of ANSI/ASHRAE 103, i.e., ANSI/ASHRAE 103-
2017. 87 FR 14622, 14630. DOE tentatively concluded that the
improvements included in ANSI/ASHRAE 103-2017 provide a more
representative average use cycle for consumer boilers, in particular
for two-stage and modulating boilers, and that the change would not
materially alter the burden or cost of conducting an AFUE test. Id. DOE
also noted that test data indicate the update to the 2017 edition of
ASHRAE 103 could result in changes to the measured AFUE of two-stage
and modulating boilers ranging from -0.50 percent to 0.23 percent, with
no discernable trend in the direction or magnitude of change, and that
several commenters indicated incorporating ANSI/ASHRAE 103-2017 would
likely not impact rated values significantly. 87 FR 14622, 14631. DOE
sought further comment on its proposal to incorporate by reference
ANSI/ASHRAE 103-2017, the potential impact on ratings and whether
retesting would be required. Id.
Rheem agreed with DOE's tentative determination that the proposed
amendments would result in minimal differences in AFUE ratings but
requested that DOE test a representative sample of minimally compliant
consumer boilers to determine the effect. Rheem requested that DOE
provide this test data in the final rule and assess the impacts on the
ongoing energy conservation standards rulemaking. Rheem additionally
suggested that DOE could provide an enforcement policy to state that
models tested and certified prior to the effective date of the test
procedure final rule would be tested to the current appendix N test
procedure during an enforcement investigation. (Rheem, No. 18 at p. 3-
4)

[[Page 15519]]

As discussed, DOE's assessment of the changes in ANSI/ASHRAE 103-
2017, along with stakeholder comments provided throughout this
rulemaking, indicate that the only update in the industry test
procedure with the potential to impact ratings would be the change in
cycle times. This topic is discussed in detail in section III.D.2.c of
this document. The updated cycle times pertain to condensing boilers,
which employ heat exchanger technologies with efficiency performance
that surpasses the current minimum AFUE requirements for boilers at 10
CFR 430.32(e)(2)(iii). As discussed in section III.D.2.c of this
document, DOE conducted testing to determine that the impact on AFUE
ratings of this change would be minimal. Based on this information, DOE
has determined that the amendments to the consumer boilers test
procedure will not have a significant or substantive impact on ratings,
nor affect compliance of any products.
On January 10, 2022, ASHRAE and ANSI approved a 2022 edition of
ASHRAE 103 (i.e., ``ANSI/ASHRAE 103-2022''). DOE did not discuss ANSI/
ASHRAE 103-2022 in the March 2022 NOPR, and parties commenting in
response to the March 2022 NOPR did not indicate that DOE should
consider incorporating by reference ANSI/ASHRAE 103-2022. A March 4,
2022, online publication by ANSI states that ANSI/ASHRAE 103-2022
includes mostly editorial changes and quality improvements to test duct
and plenum figure, the system number table, and figures for the surface
heat transfer coefficient and coefficient of radiation.\16\ Given that
stakeholders provided general support for adopting ANSI/ASHRAE 103-
2017, and that the updates in ANSI/ASHRAE 103-2022 do not substantively
change the industry test procedure DOE is not considering ANSI/ASHRAE
103-2022 in this rulemaking.
---------------------------------------------------------------------------

\16\ Brad Kelechava, ``ANSI/ASHRAE 103-2022: AFUE Testing of
Residential Furnaces and Boilers,'' The ANSI Blog, March 4, 2022,
<a href="http://blog.ansi.org/ansi-ashrae-103-2022-fuel-efficiency-afue-testing/#gref">blog.ansi.org/ansi-ashrae-103-2022-fuel-efficiency-afue-testing/#gref</a>. Last accessed October 5, 2022.
---------------------------------------------------------------------------

The following subsections discuss the updates in ANSI/ASHRAE 103-
2017 with respect to ANSI/ASHRAE 103-1993.
a. Post-Purge Time
Power vented units, power burner units, and forced-draft units use
a combustion blower to exhaust the flue gas during operation. ``Post
purge'' is defined in both ANSI/ASHRAE 103-1993 and ANSI/ASHRAE 103-
2017 as ``the design that permits the continued operation of the
combustion blower in a power vented unit, power burner unit, or forced-
draft unit for a period of time after the main burner is shut off for
the purpose of venting of residential flue gas in the heat exchanger
and the venting system.'' For the determination of off-cycle flue
losses, it is necessary to demarcate when the boiler has entered its
off-cycle after completion of the post-purge period, especially since
post-purge periods can last several minutes. Section 8.7 of appendix N
specifies the timing of flue temperature measurements during the off-
cycle portion of the test method based on the length of the post-purge
period. Section 8.7 of appendix N generally corresponds to section
9.5.2.1 of ANSI/ASHRAE 103-1993, except that section 8.7 of appendix N
specifies that when the post-purge time is less than or equal to 30
seconds, it can be set to 0 and the cool-down test be conducted as if
there is no post-purge; while section 9.5.2.1 of ANSI/ASHRAE 103-1993
specifies that if post-purge time is less than or equal to 5 seconds,
it shall be tested as if there is no post-purge. Additionally, the
length of the post-purge cycle is used as one criterion for determining
whether the heat-up and cool-down tests can optionally be omitted.
Section 8.10 of appendix N generally corresponds to section 9.10 of
ANSI/ASHRAE 103-1993, and both sections require a post-purge period of
less than 5 seconds to optionally omit the heat-up and cool-down tests.
Section 9.5.2.1 of ANSI/ASHRAE 103 was updated in the 2017 version
to match DOE's requirement that if the post-purge period is 30 seconds
or less, it shall be tested as if there is no post-purge. Additionally,
in the March 2022 NOPR, DOE identified the post-purge time threshold
being increased to 30 seconds in the criterion for determining whether
the ``Optional Test Procedures for Conducting Furnaces and Boilers that
have no OFF-Period Flue Loss'' is applicable as a change in ANSI/ASHRAE
103-2017. DOE proposed to adopt the 30-second threshold in the newly
proposed appendix EE, consistent with the change to ANSI/ASHRAE 103-
2017. 87 FR 14622, 14628.
BWC stated that it appreciated DOE's inclusion of the change in
post-purge time length to 30 seconds. (BWC, No. 19, p. 2-3)
Additionally, in the March 2022 NOPR, DOE proposed minor changes to
the test method for models with post-purge times longer than 3 minutes,
consistent with the updates included in ANSI/ASHRAE 103-2017. 87 FR
14622, 14631. Specifically, section 9.5.2.1 of ANSI/ASHRAE 103-2017
requires that for cases where the post-purge period is greater than 3
minutes, an additional measurement of the flue gas temperature during
the cool-down test is required at the midpoint of the post-purge
period. DOE proposed to adopt a harmonizing change in the newly
proposed appendix EE. 87 FR 14622, 14631 and 14654.
DOE did not receive any comments regarding this proposal. For the
reasons discussed in the March 2022 NOPR, DOE is finalizing this
amendment to section 8.5(d) of appendix EE.
b. Calculations for Omission of Heat-Up and Cool-Down Tests
The current test procedure for consumer boilers allows certain
units to omit the cool-down and heat-up tests. These include units that
have been determined to have no measurable airflow through the
combustion chamber and heat exchanger during the burner off-period and
that have minimal post-purge periods (see section III.D.1.a of this
document for discussion of post-purge time). For these boilers, the
off-cycle losses are expected to be minimal. However, off-cycle losses
(typically determined during the cool-down and heat-up tests) must be
accounted for when determining the heating seasonal efficiency,
Effy<INF>HS</INF>. Section 8.10 of appendix N currently states, ``In
lieu of conducting the cool-down and heat-up tests, the tester may use
the losses determined during the steady-state test described in section
9.1 of ASHRAE 103-1993 when calculating heating seasonal efficiency,
Effy<INF>HS</INF>.'' Accordingly, sections 10.2 and 10.3 of appendix N
provide the appropriate equations to use when calculating
Effy<INF>HS</INF> if the cool-down and heat-up tests are omitted per
section 8.10 of appendix N. These equations are provided in sections
10.2 and 10.3 of appendix N because they were not included in ANSI/
ASHRAE 103-1993.
As discussed in the March 2022 NOPR, ANSI/ASHRAE 103-2017 makes
several updates to include these equations, and the equations in ANSI/
ASHRAE 103-2017 are identical to those in appendix N. 87 FR 14622,
14629. Due to this harmonizing update, DOE proposed not to include
these equations in the new appendix EE and to instead directly
reference the relevant sections in ANSI/ASHRAE 103-2017 (11.3.11.3,
11.5.11.1, and 11.5.11.2). 87 FR 14622, 14631. DOE did not receive
comment on this topic and is finalizing this amendment as proposed in
the March 2022 NOPR.

[[Page 15520]]

c. Cycle Timings
ANSI/ASHRAE 103-2017 includes calculations, originally included in
ANSI/ASHRAE 103-2007, for determining the average on-time and off-time
per cycle for two-stage and modulating boilers, rather than assigning
fixed values as in ANSI/ASHRAE 103-1993. DOE received comments in
response to the May 2020 RFI generally indicating that these updated
cycle timings are more representative. DOE referenced test data from
the previous rulemaking to ascertain the potential impact of this
update and tentatively determined that the new method would be more
representative and not unduly burdensome and have minimal impact on
AFUE ratings. 87 FR 14622, 14628. Therefore, DOE proposed to adopt the
updated cycle times via adoption of the ASHRAE 103-2017 as the
reference standard in the newly proposed appendix EE. 87 FR 14622,
14630.
In addition, DOE discussed that data collected for the January 2016
Final Rule \17\ for three models of condensing, modulating boilers
showed that the changes in on-cycle and off-cycle times resulted in
changes in AFUE of 0.11, -0.50, and 0.22 percent, respectively. For two
models of non-condensing, modulating boilers, calculating the AFUE
based on the on-cycle and off-cycle times in ANSI/ASHRAE 103-2007
changed the AFUE by 0.11 and -0.14 percent, respectively. 87 FR 14622,
14630.
---------------------------------------------------------------------------

\17\ These data were presented at a public meeting for the March
11, 2015, NOPR pertaining to test procedures for furnaces and
boilers and can be found at <a href="http://www.regulations.gov/document/EERE-2012-BT-TP-0024-0021">www.regulations.gov/document/EERE-2012-BT-TP-0024-0021</a>.
---------------------------------------------------------------------------

In response to the March 2022 NOPR, BWC stated that it agreed with
DOE's conclusion that the new average use cycle calculations from ANSI/
ASHRAE 103-2017 are more representative for modulating boilers and have
little impact on efficiency ratings. (BWC, No. 19 at p. 4) The CA IOUs
stated the ANSI/ASHRAE 103-2017 on/off time per cycle more accurately
represents the typical operation for two-stage, modulating, and
condensing boiler technologies. (CA IOUs, No. 20 at p. 1)
AHRI requested that DOE provide more data regarding the impacts of
cycle timing on condensing models. (AHRI, No. 26 at p. 3)
In response to this request, DOE has conducted testing on two
additional modulating condensing boilers to investigate the impact of
the revised cycle timings on AFUE. Data collected from this testing is
shown in Table III.1. For this investigation, DOE used the updated
steady-state efficiency calculation method discussed in section III.E
of this final rule for both the ANSI/ASHRAE 103-1993 and ANSI/ASHRAE
103-2017 results such that the only variable influencing differences in
AFUE ratings would be the cycle timings.

Table III.1--Impact of Cycle Timings on AFUE for Modulating Condensing Boilers
----------------------------------------------------------------------------------------------------------------
ANSI/ASHRAE 103-1993 ANSI/ASHRAE 103-2017
------------------------------------------------------------------- Change in AFUE
Model Cycle timings Cycle timings (percent)
(mm:ss) AFUE (percent) (mm:ss) AFUE (percent)
----------------------------------------------------------------------------------------------------------------
Unit No. 1................... 15:00 on/15:00 90.98 23:10 on/11:05 91.43 +0.45
off. off.
Unit No. 2................... 15:00 on/15:00 91.61 20:29 on/11:50 91.46 -0.15
off. off.
----------------------------------------------------------------------------------------------------------------

As indicated in Table III.1, the change in cycle timings resulted
in insignificant changes to the AFUE values (+0.45 percent and -0.15
percent). These additional sample points are consistent with DOE's
tentative determination that impacts to AFUE would be minimal as a
result of the updated cycle timings in ANSI/ASHRAE 103-2017. Therefore,
manufacturers would not be required to retest and rerate consumer
boilers due to this change. Based on the discussion provided in the
March 2022 NOPR, consideration of comments from interested parties, and
this additional test data, DOE has determined that the updated approach
in ANSI/ASHRAE 103-2017 increases the representativeness of the test
procedure without being unduly burdensome.
During its testing of these two boilers, DOE recognized that the
determination of cycle timings in Table 7 of ANSI/ASHRAE 103-2017 does
not specify the precision to which these timings (t<INF>ON</INF> and
t<INF>OFF</INF>) should be calculated (i.e., to the nearest minute or
second). ANSI/ASHRAE 103-2017 provides no indication of whether these
cycle timings can or should be rounded. Acknowledging that many testing
facilities may only be able to time the burner cycling operation of the
boiler under test to the nearest second, DOE is providing additional
specification in appendix EE to require that calculated cycle timings
shall be rounded to the nearest second. This clarification is not
expected to impact results significantly but serves to improve
repeatability and reproducibility of test results by clarifying the
duration of the cycle time.
d. Oversize Factor
The oversize factor for a boiler indicates the ratio between the
boiler's nominal capacity and the home's heating load. This factor is
represented by the symbol ``[alpha]'' and is determined in sections
11.2.8.3 and 11.4.8.3 of ANSI/ASHRAE 103-1993 and sections 11.2.8.2 and
11.4.8.2 of ANSI/ASHRAE 103-2017.
ANSI/ASHRAE 103-2017 updates the method for calculating the
oversize factor. While the oversize factor was calculated from a lookup
table based on design heating requirement (``DHR'') in ANSI/ASHRAE 103-
1993, ANSI/ASHRAE 103-2017 assigns a constant value of 0.70 to [alpha]
to represent the national average oversize factor. Based on DOE's
assessment of its test data, DOE stated in the March 2022 NOPR that
this change would be unlikely to have a substantive impact on AFUE
ratings because the calculations are not particularly sensitive to
changes in the oversize factor value. Specifically, DOE reviewed test
data for three modulating, condensing boilers and found that the change
in oversize factor from a calculated value, as specified in ANSI/ASHRAE
103-1993, to 0.7 changed the AFUE rating by 0.01 AFUE percentage points
or less for all 3 models. 87 FR 14622, 14629. In the March 2022 NOPR,
DOE proposed to adopt the constant 0.7 oversize factor through
incorporation by reference of ANSI/ASHRAE 103-2017. Id.
BWC supported DOE's proposal to adopt the constant 0.7 oversize
factor through incorporation of ANSI/ASHRAE 103-2017. BWC's analysis of
this proposal demonstrated that adopting this approach would not have a
significant impact on overall product efficiency. (BWC, No. 19 at p. 3)
Busse stated that the oversize factor should be a constant value
less than 0.4

[[Page 15521]]

based on an Air Conditioning Contractors of America (``ACCA'')
equipment selection checklist \18\ indicating to installers that the
selected equipment should be less than or equal to 140 percent of the
designed total heating load. Busse commented that in the last 40 years,
it has become apparent that oversized equipment is less efficient, such
that a more appropriate oversize factor of approximately 0.35 is
justified. (Busse, No. 22 at p. 6-7)
---------------------------------------------------------------------------

\18\ ACCA ``Verifying ACCA Manual S[supreg] Procedures''
brochure, <a href="http://www.acca.org/HigherLogic/System/DownloadDocumentFile.ashx?DocumentFileKey=2f0a6828-2205-e112-745f-7215c9a85541&forceDialog=0">www.acca.org/HigherLogic/System/DownloadDocumentFile.ashx?DocumentFileKey=2f0a6828-2205-e112-745f-7215c9a85541&forceDialog=0</a>. Last accessed October 7, 2022.
---------------------------------------------------------------------------

In response, DOE notes that commenters did not provide field
statistics that would help to determine what a national average
representative oversize factor would be, nor is DOE aware of any such
data. While contractors may be oversizing boilers to a lesser degree
today than in the past, DOE expects that many replacements will be made
on a like-for-like basis such that the input capacity of the
replacement boiler will match that of the previous boiler (and thus
maintain the same oversize factor as the previous boiler). Without
sufficient nationally representative data to support deviation from the
industry-accepted oversize factor specified in ANSI/ASHRAE 103-2017,
DOE is adopting the provision to use a constant oversize factor of 0.70
through incorporation by reference of ANSI/ASHRAE 103-2017. In
addition, as discussed previously in this document and initially
discussed in the March 2022 NOPR, based on a review of its test data
DOE has determined that this change would not substantively impact on
AFUE.
e. Annual Performance Metrics
ANSI/ASHRAE 103-2017 changes the method for determining national
average burner operating hours (``BOH''), average annual fuel energy
consumption (``E<INF>F</INF>''), and average annual auxiliary
electrical energy consumption (``E<INF>AE</INF>''),\19\ especially for
two-stage and modulating products, based on a 2002 study from NIST.
---------------------------------------------------------------------------

\19\ A typographical correction to the determination of
E<INF>AE</INF> at 10 CFR 430.23(n) is discussed in section III.F.5
of this final rule.
---------------------------------------------------------------------------

The CA IOUs stated that ASHRAE 103-2017 utilizes differentiating
calculations for annual operating hours and reduced fuel input rates
that reflect real-world operation conditions of boilers that more
accurately represents the typical operation for two-stage, modulating,
and condensing boilers that spend a significant amount of time
operating at part-load conditions. (CA IOUs, No. 20 at p. 1)
These additional annual performance metrics are not required for
representations or certifications to DOE at this time. Federal Trade
Commission product labeling requirements at 16 CFR 305.8 specify that
determinations of estimated annual energy consumption, estimated annual
operating cost, and energy efficiency rating must be determined in
accordance with the testing and sampling provisions required by DOE as
set forth in subpart B of 10 CFR part 430. For boilers, the product
labeling provisions are specified at 16 CFR 305.20(f) and currently
only require AFUE to be presented. Thus, manufacturers are not required
to report BOH, E<INF>F</INF>, or E<INF>AE</INF> for consumer boilers as
of this final rule. However, manufacturers may voluntarily represent
these values. To ensure that any voluntary representations of these
values are conducted in accordance with the DOE test procedure, DOE is
adopting the revised calculation methods in ANSI/ASHRAE 103-2017 for
BOH, E<INF>F</INF>, and E<INF>AE</INF>.
f. Measurement of Relative Humidity
The current DOE test procedure at appendix N, through incorporation
by reference of ANSI/ASHRAE 103-1993, specifies limitations on the
relative humidity of the ambient air of the test chamber when testing a
condensing boiler. Sections 9.2 and 9.8.1 of ANSI/ASHRAE 103-1993
state, ``The humidity of the room air shall at no time exceed 80
percent'' but do not provide instruction on the instrumentation
necessary to measure the relative humidity. ANSI/ASHRAE 103-2017
provides new requirements in section 8.5.1 to follow ANSI/ASHRAE 41.6-
2014 in order to measure relative humidity for testing condensing
boilers. Because the DOE test method and ANSI/ASHRAE 103-1993 currently
limit relative humidity allowed during testing, DOE reasoned in the
March 2022 NOPR that relative humidity already must be measured under
the current procedure; thus, DOE tentatively concluded that the method
prescribed by ANSI/ASHRAE 103-2017 would likely be similar to current
practices and requested comment on this topic. 87 FR 14622, 14636-
14637.
Busse suggested that DOE should verify that ANSI/ASHRAE 41.6-2014
includes precision and calibration requirements. (Busse, No. 22 at p.
9-10) DOE has reviewed ANSI/ASHRAE 41.6-2014 in detail and notes that
it provides setup and calibration methods for both psychrometers and
hygrometers (two types of instruments which can be used to measure
relative humidity). Section 6 of ANSI/ASHRAE 41.6-2014 provides
calibration requirements, and sections 7 and 8 of ANSI/ASHRAE 41.6-2014
provide measurement methods, precision requirements, and measurement
uncertainty analysis.
As discussed further in section III.K of this document, DOE
received comments indicating that introducing these new requirements
for measurement and instrumentation would not be unduly burdensome to
industry. In this final rule, DOE is incorporating by reference ANSI/
ASHRAE 41.6-2014 in appendix EE for the purpose of performing the
required humidity measurement.
2. IEC 62301 and ASTM D2156-09
DOE noted in the May 2020 RFI that the version of IEC 62301
currently incorporated by reference in appendix N is still the most
recent version, and the most recent iteration of ASTM D2156-09 is a
version reapproved in 2018 that did not contain any changes from the
2009 version. 85 FR 29352, 29355. DOE did not receive any comments
pertaining to its incorporation by reference of IEC 62301 or ASTM
D2156-09 and in the March 2022 NOPR proposed to maintain the current
reference to IEC 62301, and to update the reference to ASTM D2156-09 to
reflect the version that was reapproved in 2018. 87 FR 14622, 14628.
DOE did not receive any comments related to its incorporation by
reference of these standards. In this final rule, DOE is finalizing
their adoption for appendix EE as proposed.

E. Steady-State Efficiency for Condensing Modulating Boilers

In the May 2020 RFI and the March 2022 NOPR, DOE discussed that
ANSI/ASHRAE 103-1993 and ANSI/ASHRAE 103-2017 yield a circular
reference when calculating the steady-state efficiency for condensing
modulating boilers. 85 FR 29352, 29357; 87 FR 14622, 14629.
As discussed in the March 2022 NOPR, the circular reference arises
within the calculation of steady-state efficiencies at maximum and
minimum input rate, which depends in part on the steady-state heat loss
due to condensate going down the drain at the maximum and reduced input
rates. (See section 11.5.7.3 of ANSI/ASHRAE 103-2017, which refers to
section 11.3.7.3.) The steady-state heat loss due to condensate going
down the drain at the maximum and minimum input rates is calculated in
part based on the national average outdoor air temperature at the
maximum and minimum input rates.

[[Page 15522]]

(See section 11.5.7.2 of ANSI/ASHRAE 103-2017, which refers to section
11.3.7.2.) The national average outdoor air temperatures at the maximum
and minimum input rates are both a function of the balance point
temperature. (See section 11.5.8.3 of ANSI/ASHRAE 103-2017, which
refers to section 11.4.8.3.) The balance point temperature is
calculated based on the oversize factor at maximum input rate (which
is, as discussed previously, a constant value in ANSI/ASHRAE 103-2017)
and the ratio of the heating capacity at the minimum input rate to the
heating capacity at the maximum input rate. (See section 11.5.8.4 of
ANSI/ASHRAE 103-2017, which references section 11.4.8.4.) The heating
capacities at the minimum and maximum input rates are calculated based
in part on the steady-state efficiencies at minimum and maximum input
rates, respectively. (See section 11.5.8.1 of ANSI/ASHRAE 103-2017,
which references section 11.4.8.1.) If the calculations were
interpreted to refer back to the steady-state efficiencies at minimum
and maximum input rates for a modulating, condensing model, as
determined by section 11.5.7.2 of ANSI/ASHRAE 103-2017, a circular
reference would result.
However, since there is no specific instruction to use the values
as calculated by section 11.5.7.2, DOE stated in the March 2022 NOPR
that it interprets ANSI/ASHRAE 103-2017 to instruct that the steady-
state efficiency at maximum and reduced input rates be determined as
specified in section 11.4.8.1, which refers to section 11.4.7, which in
turn refers to section 11.2.7 for the calculation of steady-state
efficiency for non-condensing, non-modulating boilers. 87 FR 14622,
14629. The steady-state efficiencies at maximum and minimum input
calculated using section 11.2.7 can then be used to obtain values for
output capacities at the maximum and reduced input, which are needed to
calculate the balance point temperature, the average outdoor air
temperature at maximum and minimum input, and finally the heat loss due
to condensate going down the drain at maximum and minimum input rates.
Id.
In the March 2022 NOPR, DOE proposed to add provisions to clarify
the approach for calculating steady-state efficiencies at maximum and
minimum input rates for condensing, modulating boilers using ANSI/
ASHRAE 103-2017. 87 FR 14622, 14629. Specifically, DOE proposed to
codify provisions in section 10.1.2 of appendix EE to explain how to
calculate these values without a circular reference, ultimately by
referring back to section 11.2.7 of ANSI/ASHRAE 103-2017. 87 FR 14622,
14655.
Crown, U.S. Boiler, BWC, Rheem, A.O. Smith, AHRI, and AGA & APGA
all supported DOE's proposal to provide additional specification that
would avoid a circular reference in the test procedure. (A.O. Smith,
No. 24 at p. 3; AGA & APGA, No. 25 at p. 2) Rheem recommended that each
subsection in section 10.1.2 of appendix EE should not say ``previous
step'' but should refer to the appropriate subsection. Specifically,
Rheem recommended that DOE present an equation for balance point
temperature, T<INF>C</INF>, in which the variables used in the equation
reference the relevant sections in ANSI/ASHRAE 103-2017. (Rheem, No. 18
at p. 3) Crown, U.S. Boiler, BWC, and AHRI all recommended the same
revision for section 10.1.2 to improve the clarity of the section.
(Crown, No. 16 at p. 3; U.S. Boiler, No. 17 at p. 2-3; BWC, No. 19 at
p. 3; AHRI, No. 26 at p. 2-3) Specifically, the commenters recommended
revising section 10.1.2 to replace the output capacity parameters
Q<INF>OUT,R</INF> and Q<INF>OUT</INF> as follows:
10.1.2 Calculate the balance point temperature (T<INF>C</INF>) for
condensing, modulating boilers by using the following equation in place
of that referenced by 11.5.8.4 [of ANSI/ASHRAE 103-2017]:
[GRAPHIC] [TIFF OMITTED] TR13MR23.000

Where:

T<INF>SH</INF> = typical average outdoor temperature at which a
boiler starts operating, 65 [deg]F
T<INF>OA,T</INF> = the typical outdoor design temperature, 5 [deg]F
[alpha] = oversize factor, as defined in 11.4.8.2 [of ANSI/ASHRAE
103-2017]
Q<INF>IN</INF> = steady-state nameplate maximum fuel input rate
Q<INF>IN,R</INF> = steady-state reduced input fuel input rate
L<INF>S,SSR</INF> = average sensible heat loss at steady state,
reduced input operation
L<INF>S,SS</INF> = average sensible heat loss at steady state,
maximum input operation

In reviewing this equation, DOE agrees that the recommended
equation adequately resolves the circular reference issue in the same
manner as DOE proposed in the March 2022 NOPR, but with a simplified
approach to specifying the correct calculations for determining the
steady-state efficiency for condensing modulating boilers. Rather than
determining Q<INF>OUT</INF> and Q<INF>OUT,R</INF> based on the steady-
state efficiencies Effy<INF>SS</INF> and Effy<INF>SS,R</INF> (using
section 11.2.7 of ANSI/ASHRAE 103-2017) to calculate T<INF>C</INF>, the
suggested equation simply inserts the appropriate variables directly
into the equation for T<INF>C</INF>, providing the same result. DOE is
therefore adopting this revised equation in section 10.1.3 of appendix
EE.

F. Corrections and Clarifications

1. Off-Cycle Losses
In response to the March 2022 NOPR, several commenters indicated
that ANSI/ASHRAE 103-2017 has a typographical error in the equations
used to determine L<INF>I,OFF1</INF> and L<INF>S,OFF1</INF> (off-cycle
infiltration and sensible losses, respectively). Specifically, Crown
and U.S. Boiler stated there is an error in section 11.2.10.8 of ANSI/
ASHRAE 103-2017 for the calculation of L<INF>I,OFF1</INF>. Crown and
U.S. Boiler stated that the equation for L<INF>I,OFF1</INF> in ANSI/
ASHRAE 103-1993 was erroneous because Q<INF>IN</INF> was multiplied by
60 when it should have been divided by 60. According to Crown and U.S.
Boiler, ASHRAE attempted to correct this error in ANSI/ASHRAE 103-2007,
but inadvertently copied the equation for L<INF>S,OFF1</INF> to
L<INF>I,OFF1</INF> for units having post-purge times below 3 minutes,
and this error was not corrected in the 2017 edition. (Crown, No. 16 at
p. 3; U.S. Boiler, No. 17 at p. 3) Similarly, Rheem identified this
issue involving the factor of 60 in the equations for
L<INF>S,OFF1</INF> and L<INF>I,OFF1</INF> and asked DOE to evaluate the
impact on ratings. (Rheem, No. 18, p. 6)
DOE has examined the equations for L<INF>S,OFF1</INF> and
L<INF>I,OFF1</INF> in ANSI/ASHRAE 103-2017 and understands that the
factor of 60 is used to convert the cycle times (reported in minutes)
into hours because the input rate is expressed in terms of Btu/h. Thus,
the cycle times must be divided by 60 to convert these values into
hours. Section 11.2.10.6 of ANSI/ASHRAE 103-2017 performs this
operation correctly for determining L<INF>S,OFF1</INF>, but the factor
of 60 is used incorrectly in sections 11.2.10.6 and 11.2.10.8 of ANSI/
ASHRAE 103-1993.
As Crown and U.S. Boiler indicated, industry has been aware of this
error

[[Page 15523]]

since the development of ANSI/ASHRAE 103-2007. As such, DOE expects
that current ratings are determined based on the corrected use of the
factor of 60. In particular, DOE is aware that the Gas Appliance
Manufacturers Association (GAMA) \20\ developed a computer program to
calculate AFUE.\21\ DOE has reviewed a version of this program (dated
October 15, 2003) and determined this calculation was corrected in the
underlying code. Based on this finding, correcting the use of the
factor of 60 (by incorporating by reference ANSI/ASHRAE 103-2017)
should not affect the ratings of products which have already been
tested and certified. Furthermore, these calculations apply only to
consumer boilers that have system numbers 2, 3, or 4 with post-purge
times greater than 30 seconds, which DOE understands to be a relatively
low fraction of the market based on its own compliance testing.
---------------------------------------------------------------------------

\20\ GAMA and the Air-Conditioning and Refrigeration Institute
(ARI) merged in 2008 to form AHRI.
\21\ In the May 2020 RFI, DOE discussed the industry-developed
computer program that calculates AFUE based on ANSI/ASHRAE 103-1993
``AFUE v1.2.'' This software was most recently updated in April
2004. 85 FR 29352, 29356.
---------------------------------------------------------------------------

DOE notes that section 11.2.10.8 of ANSI/ASHRAE 103-1993 provided
the correct equation for L<INF>I,OFF1</INF> for models with post-purge
periods that are less than or equal to 3 minutes (albeit with the
aforementioned error with the factor of 60).
The equation for L <INF>I,OFF1</INF> for models with post-purge
periods that are greater than to 3 minutes is corrected in ANSI/ASHRAE
103-2017 and is adopted in this final rule through incorporation by
reference.
2. Conversion Factor for British Thermal Units
In the March 2022 NOPR, DOE noted inconsistencies in the conversion
factors from watts (W) or kilowatts (kW) to British thermal units per
hour (Btu/h), in which some sections used a conversion factor of 3.412
and other sections use 3.413. 87 FR 14622, 14634. DOE stated that the
conversion factor between watts and Btu/h is generally accepted to be 1
watt = 3.412142 Btu/h (or 1 Btu/h = 0.2930711 watts), as published in
the 2021 ASHRAE Handbook--Fundamentals.\22\ Id. This value is more
appropriately rounded to 3.412 W/(Btu/h); therefore, DOE proposed
correcting the test procedures to use 3.412 W/(Btu/h) in all
calculations where 3.413 W/(Btu/h) was previously used. Id. DOE stated
in the March 2022 NOPR that it did not expect this correction to affect
AFUE ratings. Id.
---------------------------------------------------------------------------

\22\ 2021 ASHRAE Handbook--Fundamentals (I-P Edition). Peachtree
Corners, GA: American Society of Heating, Refrigeration and Air-
Conditioning Engineers, 2021. Available at <a href="http://www.ashrae.org/technical-resources/ashrae-handbook/description-2021-ashrae-handbook-fundamentals">www.ashrae.org/technical-resources/ashrae-handbook/description-2021-ashrae-handbook-fundamentals</a>.
---------------------------------------------------------------------------

DOE did not receive comments on this topic. For the reasons
discussed here and in the March 2022 NOPR, this final rule implements a
conversion factor of 3.412 in each instance within new appendix EE. DOE
also amends appendix N--which will remain applicable to consumer
furnaces other than boilers--to use the corrected conversion factor.
3. Oil Pressure Instrumentation Error
Section 6.3 of ANSI/ASHRAE 103-2017 states, ``Instruments for
measuring gas, oil, air, water, and steam pressure shall be calibrated
so that the error is no greater than the following.'' However, the
specifications that follow omit the instrumentation requirements
applicable to measuring oil pressure. Section 6.3(b) of ANSI/ASHRAE
103-1993 included the oil pressure specification.
In response to the March 2022 NOPR, Rheem commented that DOE should
add the oil pressure instrumentation specification from ANSI/ASHRAE
103-1993 to section 5 of the new appendix EE test procedure. (Rheem,
No. 18 at p. 6)
This final rule reinstates the omitted provisions from section 6.3
of ANSI/ASHRAE 103-1993 in section 5 of appendix EE.
4. Gas Inlet Conditions
Section 7.1 of appendix N references Table 1 of ANSI/ASHRAE 103-
1993 for maintaining the gas supply, ahead of all controls for a
furnace,\23\ at an acceptable test pressure. The natural gas inlet
pressure shall be between the ``normal'' and ``increased'' values shown
in Table 1 of ANSI/ASHRAE 103-1993. Table 1 in ANSI/ASHRAE 103-2017
provides identical gas inlet pressures to those in ANSI/ASHRAE 103-1993
(this table is presented in section 8.2.1.3 of ASHRAE 103-2017, which
is excluded from reference in the current appendix N test procedure).
Table 1 also specifies the specific gravity of the test gases. The
pressures and specific gravity of the test gases are reproduced in
Table III.2 of this document.
---------------------------------------------------------------------------

\23\ This term refers to the broader definition of ``furnace,''
which includes warm air furnaces and boilers.

Table III.2--Natural Gas Inlet Pressures and Specific Gravity of Test Gases in Table 1 of ANSI/ASHRAE 103-1993
and ANSI/ASHRAE 103-2017
----------------------------------------------------------------------------------------------------------------
Test pressure (inches water
column) Specific
Type -------------------------------- gravity (air =
Normal Increased 1.0)
----------------------------------------------------------------------------------------------------------------
Natural......................................................... 7.0 10.50 .65
Manufactured.................................................... 3.5 5.25 .38
Butane.......................................................... 11.0 13.00 2.00
Propane......................................................... 11.0 13.00 1.53
----------------------------------------------------------------------------------------------------------------

In response to the March 2022 NOPR, Crown and U.S. Boiler stated
that the gas inlet pressure requirements in section 8.2.1.3 of ANSI/
ASHRAE 103-2017 are appropriate and necessary for units with pilot
lights because most pilots have no pressure regulation within the
appliance itself, and thus the input rate of the pilot is determined in
large part by the inlet pressure. Crown and U.S. Boiler noted, however,
that since continuous standing pilots are prohibited by EPCA on
consumer boilers, such restrictive requirements on the gas inlet
pressure are no longer necessary in the Federal test procedure and may
place undue burden on test labs. Crown and U.S. Boiler commented that
maintaining a 7.0 inches water column (``in. w.c.'') minimum inlet
pressure is not always possible in some test labs, nor is it necessary
as long as the regulator outlet pressure can be maintained, and the
nameplate input

[[Page 15524]]

achieved. Crown and U.S. Boiler further indicated that expensive gas
booster equipment may be necessary to meet the 7.0 in. w.c. minimum.
Crown and U.S. Boiler stated that gas appliances are generally listed
for use up to 14.0 in. w.c. inlet pressure, so there is also no reason
to reduce this pressure to 10.5 in. w.c. on a boiler without a
continuous pilot in order to provide results that are repeatable and
representative of what can be expected in the field. In order to afford
labs greater flexibility while still preventing boilers from being
tested at gas inlet pressures for which they are not intended to be
used in the field, Crown and U.S. Boiler suggested replacing the second
sentence of section 8.2.1.3 of ANSI/ASHRAE 103-2017 with: ``The gas
supply, ahead of all controls for a furnace, shall be maintained at a
test pressure within the upper and lower limits shown in the
manufacturer's instructions or on the boiler itself. In the absence of
any such limits, the gas supply pressure shall be maintained between
the normal and increased values shown in Table 1 of ANSI/ASHRAE 103-
2017.'' (Crown, No. 16 at p. 2-3; U.S. Boiler, No. 17 at p. 2)
Busse urged DOE to modify the language in section 7.1 of appendix
EE to include the term ``approximately'' when referring to meeting the
specific gravity requirements in Table 1 of ANSI/ASHRAE 103-2017,
asserting that the omission of this term suggests that DOE expects the
specific gravity to be exactly as shown in Table 1 without providing
instrument requirements for measuring. (Busse, No. 22 at p. 10)
At 42 U.S.C. 6295(f)(3)(A), EPCA mandates that gas-fired boilers
manufactured on or after September 1, 2012, must not have a constant
burning pilot. DOE agrees that the test procedure requirements in
appendix N (which reference Table 1 of ANSI/ASHRAE 103-1993) have a
greater contribution to maintaining the reproducibility and
repeatability of test results for consumer boilers with constant
burning pilots; however, it is currently unclear to DOE what the
impacts of updating the natural gas inlet pressure requirements as
suggested would be on measured efficiency ratings for boilers without
constant burning pilots. Crown and U.S. Boiler did not provide data to
indicate that their suggested approach of relying on the manufacturer's
instructions for setting natural gas inlet pressure will not
significantly impact ratings. Manufacturers have not previously
expressed concern regarding the ability to meet the inlet pressure
requirements in appendix N, and no waivers have been received for
consumer boilers that are not compatible with the inlet pressure
provisions. This suggests that manufacturers and test laboratories have
been able to meet these setup requirements since compliance with the
currently applicable appendix N test procedure has been required (July
13, 2016).
For these reasons, DOE has determined that no correction to the
natural gas inlet pressure requirements is necessary at this time and
is adopting the reference to Table 1 of ANSI/ASHRAE 103-2017 in section
7.1 of appendix EE as proposed in the March 2022 NOPR. Regarding
Busse's suggestion to include the word ``approximately'' in reference
to the specific gravity values referenced in section 7.1, DOE agrees
that the specific gravity may not be exactly as provided in Table 1 of
ANSI/ASHRAE 103-2017 because variations exist due to differences in gas
composition in supply sources. DOE understands that the purpose of
specifying the gas characteristics in Table 1 of ANSI/ASHRAE 103-2017
is to ensure that the energy content in the gas is consistent for the
repeatability and reproducibility of the test. DOE notes that explicit
tolerances are provided for the higher heating value of the gas used,
such that providing explicit tolerances for the specific gravity of the
gas would be redundant. As such, DOE is adopting Busse's suggestion to
state that the specific gravity of the gas should be ``approximately''
that shown in Table 1 of ANSI/ASHRAE 103-2017.
5. Active Mode Electrical Energy Consumption
As previously discussed, AFUE does not include active mode
electrical consumption for gas-fired and oil-fired boilers. Instead,
the DOE test procedure includes provisions for determining the average
annual auxiliary electrical energy consumption for gas-fired and oil-
fired boilers (E<INF>AE</INF>), as a separate metric from AFUE, that
accounts for active mode, standby mode, and off mode electrical
consumption. (See appendix N, section 10.4.3.) E<INF>AE</INF> is
referenced by the calculations at 10 CFR 430.23(n)(1) for determining
the estimated annual operating cost for furnaces. However, the
provisions at 10 CFR 430.23(n) include several incorrect references to
sections in appendix N. In the March 2022 NOPR, DOE proposed to correct
10 CFR 430.23(n)(1) to reference the appropriate sections of appendix N
where the currently codified provisions point to the wrong sections.
Additionally, DOE proposed to revise 10 CFR 430.23(n)(1) such that
sections in appendix N are referenced for furnaces and sections in
appendix EE are referenced for boilers. 87 FR 14622, 14633, and 14643.
DOE did not receive any comments on this topic. In this final rule,
DOE adopts these corrections as proposed.
6. Circulator Pumps
Section 8.2 of the proposed appendix EE from the March 2022 NOPR
included instructions on the electrical energy consumption measurements
for various boiler components in order to calculate PE, the electrical
power involved in burner operation. 87 FR 14622, 14654. It stated that
the measurement of PE must include the boiler pump if so equipped. Id.
In response to the March 2022 NOPR, Rheem noted that section 2 of
the proposed appendix EE defines a ``boiler pump'' \24\ as being
separate from the circulating water pump; however, the term
``circulating water pump'' is not defined in the proposed appendix EE
or ANSI/ASHRAE 103-2017. Rheem recommended that DOE add a definition
for ``circulating water pump'' to clarify the difference between these
pumps and to reduce confusion when performing the procedure in section
8.2 of appendix EE, which refers to both pump types. (Rheem, No. 18 at
p. 5-6)
---------------------------------------------------------------------------

\24\ Section 2.2 of appendix N defines a ``boiler pump'' as a
pump installed on a boiler that is separate from the circulating
water pump.
---------------------------------------------------------------------------

DOE notes that the definition for ``boiler pump'' was established
in the January 2016 Test Procedure Final Rule. 81 FR 2628, 2647. In the
January 2016 Test Procedure Final Rule, in describing devices that use
power during the active mode, DOE discussed a secondary pump for
boilers (i.e., boiler pump) used to maintain a minimum flow rate
through the boiler heat exchanger, which is most typically associated
with condensing boiler designs. Id. at 81 FR 2633. In the preamble to
the January 2016 Test Procedure Final Rule, DOE stated that it would
define a boiler pump as, ``a pump installed on a boiler that maintains
adequate water flow through the boiler heat exchanger and that is
separate from the circulating water pump;'' however, this definition
was not codified with the additional clarification that the boiler pump
maintains adequate water flow through the heat exchanger. Id. at 81 FR
2634. In order to improve the clarity of the boiler pump definition,
DOE is revising this definition to reflect the language which was
inadvertently omitted from the January 2016 Test Procedure Final Rule.
Additionally, section 9.1.2.2 of ANSI/ASHRAE 103-2017 states that,
for hot water boilers, the circulating water

[[Page 15525]]

pump nameplate power is to be used to determine the electrical power to
the circulating water pump (BE), and if the pump nameplate power is not
available, use the pump power listed in the water pump manufacturer's
literature or use 0.13 kW. In response to the March 2022 NOPR, Busse
suggested that, because circulator pumps do not have a ``nameplate''
power value, the water pump manufacturer's literature could be used
instead for calculating the value of BE. Busse also commented that the
default value of 0.13 kW in ANSI/ASHRAE 103-2017 may not be appropriate
for modern electronically commutated motor-based circulator pumps.
(Busse, No. 22 at p. 11)
At this time, DOE does not have sufficient data on circulating
water pumps used with consumer hot water boilers to specify a more
representative power draw to be used in lieu of manufacturer-reported
information (either on a nameplate or in the I&O manual). As ANSI/
ASHRAE 103-2017 is currently the industry-accepted test standard \25\
for consumer boilers, DOE expects that the provisions for circulator
pump power remain representative for current installations.
Additionally, DOE notes that the value of BE is not a factor that
determines AFUE (see section III.C for discussion about the AFUE
metric).
---------------------------------------------------------------------------

\25\ ANSI/ASHRAE 103-2022 does not provide substantive updates
to provisions for circulator pump power.
---------------------------------------------------------------------------

7. Units With Draft Hoods or Draft Diverters
Section 6.4 of appendix N provides installation instructions for
units with draft hoods or draft diverters. Among other requirements,
this section specifies installing the stack damper in accordance with
the ``I&O manual.''
In response to the March 2022 NOPR, Rheem commented that section
6.4 of appendix N appeared to have been omitted from the proposed
appendix EE. Rheem noted that these provisions are still relevant to
boilers and should be carried over into the new appendix EE test
procedure. (Rheem, No. 18 at p. 6)
The March 2022 NOPR proposed in section 6 (``Apparatus'') of
appendix EE to reference section 7 of ANSI/ASHRAE 103-2017
(``Apparatus'') including sections 7.2.3.1 and 7.3.3.1. Section 7.3.3.1
of ANSI/ASHRAE 103-2017 specifies stack and flue installation
requirements for boilers with draft hoods or draft diverters by
referencing section 7.2.3.1 of ANSI/ASHRAE 103-2017. The language in
section 7.2.3.1 of ANSI/ASHRAE 103-2017 is identical to the provisions
in section 6.4 of the current appendix N, except that section 7.2.3.1
specifies that the stack damper be installed in accordance with the
``manufacturer's instructions'' rather than the ``I&O manual''
specified in section 6.4. DOE's proposal to reference sections 7.2.3.1
and 7.3.3.1 of ANSI/ASHRAE 103-2017 through reference to section 7 in
the new appendix EE test procedure maintained the installation
instructions for units with draft hoods or draft diverters in appendix
EE. This final rule maintains the reference to section 7 of ANSI/ASHRAE
103-2017 in section 6 of appendix EE.
DOE has determined, however, that maintaining the more specific
reference to the manufacturer's I&O manual, rather than a general
reference to manufacturer's instructions, will ensure the
reproducibility of the test procedure by providing a more specific
reference to the document that must be consulted with regard to
installing the stack damper. Therefore, this final rule adds an
exception in section 6 of appendix EE to specify referencing the I&O
manual in lieu of manufacturer's instructions in section 7.2.3.1 of
ANSI/ASHRAE 103-2017.
8. Rounding of AFUE
In response to the March 2022 NOPR, Busse observed an inconsistency
between requirements to round the AFUE at 10 CFR 430.23(n)(2)(iii) and
requirements to truncate the AFUE at 10 CFR 429.18(a)(2)(vii). (Busse,
No. 22 at p. 11)
On July 22, 2022, DOE published a final rule regarding
certification requirements for several covered products and equipment,
including consumer boilers (``July 2022 Certification Final Rule''). 87
FR 43952. In an amendment established by that final rule, effective
August 22, 2022, DOE modified 10 CFR 429.18(a)(2)(vii) to state that
AFUE must be rounded to the nearest one-tenth of a percentage point.
Id. at 87 FR 43968. As this amendment provides consistency between the
certification requirement and the test procedure, no further correction
is required in this rulemaking.

G. Other Test Procedure Topics

In the course of this rulemaking, DOE solicited feedback on
additional aspects of the current test procedure for consumer boilers
to assess whether they remain representative of the energy consumption
during an average use cycle. DOE did not propose to amend the test
procedure for consumer boilers with regard to these topics in the March
2022 NOPR, and after consideration of comments received in response to
that NOPR, DOE determined not to amend the test procedure accordingly.
Comments received with regard to these topics are discussed in the
following subsections.
1. Outdoor Design Temperature
ANSI/ASHRAE 103-2017 assigns a value of 5 [deg]F for the typical
outdoor design temperature and 42 [deg]F for the average outdoor air
temperature, represented by T<INF>OA,T</INF> and T<INF>OA</INF>,
respectively. The outdoor design temperature is the lowest expected
temperature at which the boiler can satisfy the home's heating demand,
while the average outdoor air temperature is the average temperature
during the heating season.
In response to the March 2022 NOPR, Busse stated that the 5 [deg]F
outdoor design temperature used in ANSI/ASHRAE 103-1993 \26\ may be out
of date due to climate change and suggested that different outdoor
design temperatures could be assigned for furnaces and boilers. (Busse,
No. 22 at p. 4) Similarly, Busse indicated that a 42 [deg]F average
outdoor air temperature may no longer be valid based on recent climate
change data. (Busse, No. 22 at p. 11)
---------------------------------------------------------------------------

\26\ DOE notes that the same requirement is also specified in
ANSI/ASHRAE 103-2017.
---------------------------------------------------------------------------

In response, DOE notes that homes in the United States--
particularly in the Northeast region, where most boilers are
installed--still experience temperatures as low as 5 [deg]F during the
heating season \27\ despite climate change trends. DOE does not have
any data, nor did Busse or other commenters provide any such data,
suggesting a value other than 5 [deg]F that would provide more
representative test results. As such, DOE is maintaining 5 [deg]F as
the outdoor design temperature in the appendix EE test procedure for
consumer boilers.
---------------------------------------------------------------------------

\27\ For example, daily temperature data for the Albany, NY,
area for the winter of 2022 (December 1, 2021, through March 1,
2022) shows 13 days during which the observed temperature reached at
or below 5 [deg]F. The Duluth, MN, area experienced 55 days during
which the observed temperature reached at or below 5 [deg]F during
the same time period. Data for these areas are available at
<a href="http://www.weather.gov/wrh/Climate?wfo=aly">www.weather.gov/wrh/Climate?wfo=aly</a> and <a href="http://www.weather.gov/wrh/Climate?wfo=dlh">www.weather.gov/wrh/Climate?wfo=dlh</a>. Last accessed October 7, 2022.
---------------------------------------------------------------------------

Regarding the average outdoor air temperature, DOE examined average
outdoor air temperatures for the contiguous United States during the
months of October, November, December, January, February, and March
(i.e., the months during which consumer boilers would be expected to
operate).\28\ This data indicates that from

[[Page 15526]]

2012 through 2022, average outdoor air temperatures during these months
is 41 [deg]F, which aligns closely with the value of 42 [deg]F
specified in ANSI/ASHRAE 103-2017. Therefore, in this final rule, DOE
is maintaining the value of 42 [deg]F for T<INF>OA</INF> as specified
by ANSI/ASHRAE 103-2017.
---------------------------------------------------------------------------

\28\ These temperatures are published by the National Oceanic
and Atmospheric Administration and are available at
<a href="http://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/national/time-series">www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/national/time-series</a>. Last accessed October 7, 2022.
---------------------------------------------------------------------------

2. Ambient Conditions
The current test procedure for consumer boilers in appendix N,
through incorporation by reference of ANSI/ASHRAE 103-1993, specifies
that the ambient air temperature during testing must be between 65
[deg]F and 100 [deg]F for non-condensing boilers, and between 65 [deg]F
and 85 [deg]F for condensing boilers (see section 7 of appendix N and
section 8.5.2 of ANSI/ASHRAE 103-1993). In addition, the relative
humidity cannot exceed 80 percent during condensate measurement (see
section 8 of appendix N and section 9.2 of ANSI/ASHRAE 103-1993).
In the May 2020 RFI, DOE requested comment and data on the effects
of ambient temperature and relative humidity on AFUE results, whether
the current ranges of allowable conditions adversely impact the
representativeness of AFUE values or repeatability of AFUE testing, and
whether a narrower range of allowable ambient conditions would increase
testing burden. 85 FR 29352, 29356.
As discussed in the March 2022 NOPR, DOE received comments from
AHRI and manufacturers supporting the current range of allowable
operating conditions, while the CA IOUs and NEEA suggested limiting
this range to reflect the temperatures of spaces where boilers may be
installed. 87 FR 14622, 14631.
DOE investigated concerns regarding the ambient conditions as part
of the January 2016 Final Rule (see 81 FR 2628, 2638; Jan. 15, 2016).
Testing conducted in support of the January 2016 Final Rule indicated
there was no definitive impact of variation of ambient conditions on
the resultant AFUE, and DOE determined there was not adequate data to
justify changing the test procedure to narrow the ranges. In the March
2022 NOPR, DOE provided a similar tentative determination based on the
lack of sufficient evidence, and thus did not propose any changes at
that time. 87 FR 14622, 14631-14632.
In response, while the CA IOUs supported incorporation by reference
of ANSI/ASHRAE 103-2017, they encouraged DOE to reexamine the impacts
of ambient conditions on AFUE ratings by conducting additional testing.
(CA IOUs, No. 20 at p. 2) NYSERDA requested that DOE revise the test
procedure to ensure that condensing and non-condensing boilers are
tested under the same ambient conditions to allow consumers to make
informed decisions between these products. NYSERDA also requested that
DOE review the impacts of ambient temperature on boiler performance and
review the jacket loss assumptions based on likely real-world operating
conditions. Citing that DOE has not provided a further study on ambient
conditions since the 2016 rulemaking, NYSERDA urged DOE to revisit the
issue of ambient temperature impacts on consumer boiler performance and
conduct additional analysis and/or testing either as part of the
current rulemaking or in anticipation of the next statutorily mandated
review. (NYSERDA, No. 23 at p. 5)
The Joint Advocates stated they did not believe that separate
ambient conditions are necessary for non-condensing and condensing
boilers, and that the range of allowable ambient temperatures is too
broad to accurately measure energy use during a representative average
use cycle. The Joint Advocates cited course material from Continuing
Education and Development, Inc. indicating that a variation in ambient
temperature of 20 [deg]F can affect the thermal efficiency of a
commercial package boiler by over 0.5 percent, and therefore suggested
that DOE require the ambient temperature to be maintained between 65
[deg]F and 85 [deg]F for all consumer boilers. (Joint Advocates, No. 21
at p. 3)
Busse stated that a boiler tested at the current temperature and
humidity limits should perform at a higher AFUE than when tested at a
``normal'' lab condition of 70 [deg]F and 50 percent relative humidity
due to higher water vapor content and higher dew point temperature and
thus recommended limiting the test room conditions to 75 [deg]F and 55
percent relative humidity. Busse noted that the National Bureau of
Standards Information Report (``NBSIR'') recommended limits on the
original test room conditions,\29\ and that water vapor content and dew
point temperature vary significantly with temperature (specifically
providing information at 42 [deg]F [average outdoor air temperature],
70 [deg]F [``normal'' lab condition], and 85 [deg]F [maximum allowable
during AFUE test]). Busse also cited Burnham Holdings, Inc. (``BHI'')
test data for a single condensing boiler which showed a change in AFUE
of 1.3 percent when the relative humidity was changed from
approximately 30 percent to 70 percent. (Busse, No. 22 at p. 5)
---------------------------------------------------------------------------

\29\ Busse's comment references two reports from National Bureau
of Information: NBSIR 78-1543: ``Recommended Testing and Calculation
Procedures for Determining the Seasonal Performance of Residential
Central Furnaces and Boilers'' (September 1978) and NBSIR 80-2110,
``Recommended Testing and Calculation Procedures for Estimating the
Seasonal Performance of Residential Condensing Furnaces and
Boilers'' (April 1981).
---------------------------------------------------------------------------

DOE notes the data collected thus far has been on a limited sample
of boilers, and the information required to amend the ambient
conditions should reflect the array of boiler designs on the market.
The impact of the ambient air conditions would vary based on how the
ambient air interacts with the boiler during its normal operation. As
noted previously, in the January 2016 NOPR, DOE concluded that the test
data was not definitive enough to provide justification for changing
the ambient conditions. Regarding the data submitted by Busse, DOE
notes that BHI also provided that data point in a comment responding to
the May 2020 RFI (BHI, No. 11 at p. 2, 11). As discussed in the March
2022 NOPR, although BHI provided test data for a single unit showing a
difference in performance under different conditions, DOE notes that
DOE's previous test data, obtained from multiple units, did not
indicate conclusively that ambient test conditions within the current
bounds cause substantive differences in AFUE. As a result, DOE is not
amending the test procedure for consumer boilers to narrow or revise
the ambient test conditions at this time due to insufficient conclusive
evidence demonstrating the impact on AFUE for various boiler types.
3. Combustion Settings
In the course of the rulemaking for the January 2016 Final Rule, to
provide for greater consistency in burner airflow settings during
testing, DOE proposed specifying that the excess air ratio, flue oxygen
(``O<INF>2</INF>'') percentage, or flue carbon dioxide
(``CO<INF>2</INF>'') percentage be within the middle 30th percentile of
the acceptable range specified in the I&O manual. 80 FR 12876, 12883,
12906 (Mar. 11, 2015). In absence of a specified range in the I&O
manual, DOE proposed requiring the combustion airflow to be adjusted to
provide between 6.9 percent and 7.1 percent dry flue gas O<INF>2</INF>,
or the lowest dry flue gas O<INF>2</INF> percentage that produces a
stable flame, no carbon deposits, and an air-free flue gas carbon
monoxide (``CO'') ratio below 400 parts per million (``ppm'') during
the steady-state test described in section 9.1 of ANSI/

[[Page 15527]]

ASHRAE 103-2007, whichever is higher. 80 FR 12876, 12906. However,
after considering comments regarding the representativeness of the
proposal and the potential impact on rated AFUE, DOE determined in the
January 2016 Final Rule that further study was needed to determine how
such changes would impact AFUE ratings. 81 FR 2628, 2636.
In the May 2020 RFI, DOE requested comment on whether more specific
instructions for setting the excess air ratio, flue O<INF>2</INF>
percentage, and/or flue CO<INF>2</INF> percentage should be provided in
the consumer boilers test procedure, and if so, what those instructions
should entail. 85 FR 29352, 29356. DOE was particularly interested in
understanding whether such a change would improve the
representativeness of the test method, and whether it would impact test
burden.
In the March 2022 NOPR, after considering comments received in
response to the May 2020 RFI, DOE tentatively concluded that it lacked
sufficient data and information to indicate that establishing a
requirement for setting the excess air ratio, flue O<INF>2</INF>
percentage, and/or flue CO<INF>2</INF> percentage would provide ratings
that are more representative than the ratings provided under the
current approach. Therefore, DOE tentatively determined to maintain the
current test procedure and did not propose to establish a requirement
for setting the excess air ratio, flue O<INF>2</INF> percentage, and/or
flue CO<INF>2</INF> percentage. 87 FR 14622, 14633.
In response to the March 2022 NOPR, the CA IOUs encouraged DOE to
examine the impacts of excess air ratio, flue oxygen percentage, and
flue carbon dioxide percentage on AFUE ratings by conducting additional
testing. (CA IOUs, No. 20 at p. 2) The Joint Advocates also encouraged
DOE to investigate the efficiency impacts of combustion airflow
settings and to consider establishing criteria around those settings in
the test procedure in order to provide more accurate product rankings.
The Joint Advocates asserted that excess air, which can be determined
by flue gas O<INF>2</INF> and CO<INF>2</INF> concentrations, affects
combustion efficiency and, as an example, cited a 2002 fact sheet
published by the National Renewable Energy Laboratory that indicated
combustion efficiency of commercial boilers can be increased by 1
percent for each 15 percent reduction in excess air ratio.\30\ (Joint
Advocates, No. 21 at p. 3-4)
---------------------------------------------------------------------------

\30\ The fact sheet referenced by the Joint Advocates is
available at: <a href="https://www.nrel.gov/docs/fy02osti/31496.pdf">https://www.nrel.gov/docs/fy02osti/31496.pdf</a>. (Last
accessed 11/3/2022).
---------------------------------------------------------------------------

NYSERDA recommended that DOE study how excess oxygen impacts the
efficiency of the boiler operation. NYSERDA pointed out that DOE
received input from multiple stakeholders regarding changes to excess
air ratio, flue O<INF>2</INF> percentage, and/or flue CO<INF>2</INF>
percentage in the 2016 rulemaking cycle. NYSERDA urged DOE to either
revisit this proposal regarding excess oxygen or commit to further
study of this topic for a future revision. (NYSERDA, No. 23 at p. 4-5)
Busse suggested updating the test procedure to include two
requirements: (1) verify reduced input rate is 98 percent or greater
than nameplate minimum input rate and, if less than 98 percent, adjust
controls or settings as specified in the I&O manual and restart test at
maximum input rate or, if 98 percent or greater, no additional control
or setting changes are allowed; and (2) verify combustion products do
not exceed 400 parts per million air-free and there are no deposits of
carbon on the burner, and correct these conditions, if necessary, as
specified in the I&O manual. Busse stated that a reduced input rate
below 98 percent of nameplate minimum input rate would likely result in
a higher efficiency, and that requiring adjustment and restarting a
test when above 102 percent of nameplate minimum input rate could
increase test burden. Busse further stated that these provisions would
strive towards more accurate AFUE results while not greatly increasing
the testing burden. (Busse, No. 22 at p. 10)
In the January 2016 Final Rule, DOE explained that industry
stakeholders indicated that the current practice is typically to use
the CO<INF>2</INF> percentage at the ``top'' of the manufacturer's
specified range, and in some cases, even higher than that. Stakeholders
provided data suggesting that the impacts on AFUE could be significant
but variable,\31\ and there was also concern that some products may not
feature any means of providing combustion setting adjustment. Finally,
commenters indicated that DOE must evaluate the burden associated with
potential re-testing should combustion setting specifications require
manufacturers to re-rate their products. As discussed previously, DOE
ultimately agreed that further study was needed on the impacts of the
CO<INF>2</INF> percentage on AFUE and, therefore, declined to adopt the
proposed amendments. 81 FR 2628, 2635-2636. Thus, there remained a lack
of certainty regarding what settings would be most representative of
field use.
---------------------------------------------------------------------------

\31\ AHRI stated that the results of the testing of three
residential boilers that it conducted at Intertek Testing
Laboratories indicate that the proposed revised burner setup
requirements change AFUE by 0.3 percent for each 1 percent
difference in the CO<INF>2</INF> values. By contrast, Burnham stated
that based on test data that it provided, for an oil-fired hot water
boiler with an 11.5 to 12.5 percent CO<INF>2</INF> adjustment range
in the I&O manual, DOE's proposed adjustment would reduce AFUE by as
much as 1.0 percent compared to the rating under the existing test
procedure. 81 FR 2628, 2636.
---------------------------------------------------------------------------

DOE did not receive any information in response to the March 2022
NOPR that provided further clarity on this issue. Therefore, DOE has
determined that it still lacks sufficient information to indicate that
establishing a specification for excess air ratio, flue O<INF>2</INF>
percentage, and/or flue CO<INF>2</INF> percentage would provide ratings
that are more representative than the ratings provided under the
current approach, and that doing so would not be unduly burdensome.
Therefore, DOE is maintaining the current instructions and is not
establishing additional requirements specifying excess air ratio, flue
O<INF>2</INF> percentage, and/or flue CO<INF>2</INF> percentage.
4. Supplemental Test Instructions
In the March 2022 NOPR, DOE responded to comments from BHI
suggesting that DOE create a repository of supplemental test
instructions, similar to that currently in place for commercial
boilers,\32\ instead of requiring a waiver to allow for use of specific
test instructions not included in the I&O manual or the DOE test
procedure. 87 FR 14622, 14635-14636. Specifically, BHI asserted that
control systems are increasingly complex, which makes it impractical to
run the test without special tools or codes, and that there are safety
and reliability concerns with putting testing-specific instructions in
the I&O manual. BHI also asserted that the use of the waiver process
for these test instruction issues is burdensome, unnecessary, and
inconsistent with the test procedure for commercial boilers.
---------------------------------------------------------------------------

\32\ For commercial boilers, DOE provides that a certification
report may include supplemental testing instructions, if such
information is necessary to run a valid test. Specifically,
supplemental information must include any additional testing and
testing set-up instructions (e.g., specific operational or control
codes or settings) which would be necessary to operate the basic
model under the required conditions specified by the relevant test
procedure. 10 CFR 429.60(b)(4).
---------------------------------------------------------------------------

In response, DOE noted that BHI did not provide specific examples
of test instructions that would not be able to be included in the I&O
manual due to concerns about safety or reliability, and that would thus
need to be presented in a waiver. In addition, DOE noted it has not
received any petitions for waiver for any basic models of consumer
boilers,

[[Page 15528]]

indicating there is not a problem with testing absent such additional
information. Therefore, DOE did not propose to establish a repository
for test instructions for consumer boilers and stated that if testing
of a consumer boiler necessitates controls or instructions other than
those included in the I&O manual, manufacturers may petition for a
waiver under the process established at 10 CFR 430.27. DOE sought
further comment on whether supplemental test instructions are necessary
for consumer boilers. 87 FR 14622, 14636.
Rheem recommended that DOE use the I&O manual provided with the
product as the primary instruction for testing a consumer boiler, and
where a manufacturer participates in a third-party certification
program (such as AHRI's) and declares supplemental instructions for
product testing, the manufacturer should have the option to use such
instructions for audit or enforcement testing. (Rheem, No. 18 at p. 5)
A.O. Smith recommended that some supplemental instructions from
manufacturers could ensure consistency in testing, such as the need to
use the recirculation loop to prevent flashing in the heat exchanger or
instructions to remove a water temperature sensor and plug the opening.
(A.O. Smith, No. 24 at p. 5) Busse suggested that supplemental test
instructions are necessary for minimum input rate adjustment (for step-
modulating condensing boilers) and for steam boiler low water cutoff
(wherein the feature periodically turns off the burner to monitor the
settled water level and therefore prevents the boiler from operating
continuously during a steady-state test). (Busse, No. 22 at p. 9)
As discussed in the March 2022 NOPR, DOE has not received any
petitions for waivers for any basic models of consumer boilers,
indicating there is not a problem with testing absent such additional
information. Should testing of a consumer boiler necessitate controls
or instructions other than those included in the I&O manual,
manufacturers may petition for a waiver under the process established
at 10 CFR 430.27.
5. Input Rates for Step Modulating Boilers
Appendix N includes a number of specific provisions for consumer
boilers with step modulating controls. Boilers with step modulating
controls are capable of operating at reduced input rates (i.e., less
than that maximum nameplate input rate) and gradually or incrementally
increasing or decreasing the input rate as needed to meet the heating
load. The test procedure currently requires step modulating boilers to
be tested at the maximum rate and the minimum (i.e., reduced) input
rate for the steady-state test (referencing section 9.1 of ANSI/ASHRAE
103-1993), the reduced input rate for the cool-down test (referencing
section 9.5.2.4 of ANSI/ASHRAE 103-1993), and the reduced input rate
for the heat-up test (referencing section 9.6.2.1 of ANSI/ASHRAE 103-
1993). In addition, both the optional tracer gas test and the
measurement of condensate under cyclic conditions, when conducted, are
performed at the reduced input rate (referencing sections 9.7.5 and 9.8
of ANSI/ASHRAE 103-1993, respectively). ANSI/ASHRAE 103-2017 contains
the same input rate requirements for modulating boilers as ANSI/ASHRAE
103-1993.
In the May 2020 RFI, DOE requested comment on whether the existing
provisions for testing step modulating boilers appropriately reflect
the performance of such boilers. If not, DOE sought specific
recommendations on the changes that would be necessary to make the test
procedure more representative for such products. 85 FR 29352, 29357.
Commenters indicated these provisions were adequate, and DOE did not
propose any amendments to the provisions for testing step modulating
boilers in the March 2022 NOPR. 87 FR 14622, 14633.
In response to the March 2022 NOPR, BWC stated that it appreciated
DOE not proposing that step modulating units account for operation at
any additional input rates beyond those specified in the current test
procedure. BWC stated that the test methods in ANSI/ASHRAE 103-2017
sufficiently measure the performance of these units at different input
rates and are representative of a product's average use cycle. (BWC,
No. 19, p. 4)
For the reasons discussed in the March 2022 NOPR, and in
consideration of the comments received, DOE is not adopting any changes
to the provisions for testing step modulating boilers in this final
rule.
6. Return Water Temperature
The test procedure at appendix N currently requires a nominal
return water temperature (``RWT'') of 120 [deg]F to 124 [deg]F for non-
condensing boilers and 120 [deg]F <plus-minus> 2 [deg]F for condensing
boilers (see section 7 of appendix N and sections 8.4.2.3 and 8.4.2.3.2
of ANSI/ASHRAE 103-1993, which are incorporated by reference).
In response to the May 2020 RFI, the CA IOUs requested that DOE
consider adopting multiple RWTs in the amended test procedure for
consumer boilers, consistent with the methodology being developed by
the ASHRAE Standard 155P Committee for testing and rating commercial
boilers, which requires testing at multiple RWTs depending on the
operational characteristics of the boiler. As discussed in the March
2022 NOPR, DOE considers the impact of varying RWTs on field-installed
efficiency in its energy conservation standards rulemakings. In the
previous energy conservation standards rulemaking for consumer boilers,
DOE developed AFUE adjustment factors for low, medium, and high RWT
scenarios and estimated that, on average, AFUE would vary from the
rated value by 2.66 percent to +3.15 percent depending on the model
characteristics and RWT (see 81 FR 2320, 2354); however, DOE noted
there is still a wide range of potential RWTs in the field. Thus, in
the March 2022 NOPR, DOE sought additional comment on whether the RWT
requirements in the current test method and ANSI/ASHRAE 103-2017 are
representative and appropriate, and whether any specific changes to the
required conditions could improve representativeness. DOE also sought
comment on any associated test burden with changing RWTs. 87 FR 14622,
14633.
In response, the CA IOUs reiterated their request for DOE to review
whether the 120 [deg]F RWT requirement is appropriately representative
of real-world operating conditions. (CA IOUs, No. 20 at p. 2)
AHRI and AGA & APGA urged DOE to align return water temperatures
with those in ANSI/ASHRAE 103-2017. (AHRI, No. 26 at p. 3; AGA & APGA,
No. 25 at p. 2)
BWC supported DOE's tentative conclusion of including the single
return water temperature specified in ANSI/ASHRAE 103-2017 for ease of
comparison between models and manufacturers. (BWC, No. 19 at p. 4) BWC
asserted that a single condition would not increase the test burden.
(BWC, No. 19 at p. 4)
A.O. Smith commented that the current return water temperature is
representative of an average value for the wide range of operating
temperatures in the field and indicated that requiring testing to
multiple conditions may require adjustment of the standards. A.O. Smith
added that non-condensing boilers are more likely to be installed in
systems with higher supply and return water temperatures, and
condensing boilers are more likely to be installed in systems with
lower temperatures. (A.O. Smith, No. 24 at p.

[[Page 15529]]

3-4) A.O. Smith stated that testing at multiple water temperatures
would add testing burden to a test that could already span two days to
complete, and that the burden to retest and rerate products would also
include updating heat output ratings and safety certifications. (Id.)
Rheem supported maintaining the return water temperature in the
current test method, asserting that any change that could make the
return water temperature more representative would be outweighed by the
testing and certification burden on manufacturers. Specifically, Rheem
noted that slight changes to the water temperature would not produce
significantly more representative results, and major changes would
require retesting of nearly all consumer boilers. (Rheem, No. 18 at p.
4)
Crown and U.S. Boiler supported the use of the water temperatures
specified by ANSI/ASHRAE 103-2017 to reduce testing burden and
complication. Crown and U.S. Boiler stated that a single set of water
temperatures for all types of hot water boilers is appropriate to avoid
consumer confusion, increased certification burden, and departure from
the industry test method. Crown and U.S. Boiler added that changes to
these water temperatures would cause significant changes in AFUE
ratings for condensing boilers. (Crown, No. 16 at p. 3-4; U.S. Boiler,
No. 17 at p. 3-4)
NYSERDA noted that return water temperature has a significant
impact on boiler performance and urged DOE to incorporate return water
temperatures that more accurately reflect real-world conditions.
NYSERDA stated that the 120 [deg]F return water temperature is too low,
does not represent the boiler running conditions according to a
research study done by The Electric and Gas Program Administrators of
Massachusetts Part of the Residential Evaluation Program Area in
2015,\33\ and should be considered closer to 140 [deg]F. NYSERDA
claimed that the rationale for choosing the 120 [deg]F return water
temperature from 1978 is outdated and inconsistent with DOE's current
test procedure methodologies for commercial HVAC equipment. NYSERDA
recommended that DOE test at both 120 [deg]F and 140 [deg]F for return
water temperatures but stated that if DOE had to test at only one
temperature, it should be 140 [deg]F. (NYSERDA, No. 23 at p. 2-4)
---------------------------------------------------------------------------

\33\ High Efficiency Heating Equipment Impact Evaluation,
Prepared for: The Electric and Gas Program Administrators of
Massachusetts Part of the Residential Evaluation Program Area, March
2015 at 22, available at <a href="http://ma-eeac.org/wp-content/uploads/High-Efficiency-Heating-Equipment-Impact-Evaluation-Final-Report.pdf">ma-eeac.org/wp-content/uploads/High-Efficiency-Heating-Equipment-Impact-Evaluation-Final-Report.pdf</a>.
---------------------------------------------------------------------------

The Joint Advocates urged DOE to continue to investigate return
water temperatures used in the test procedure to capture more
representative performance, directing attention to data presented in
appendix 7B to DOE's preliminary analysis technical support document
(``TSD''),\34\ which indicated that there was an impact of return water
temperature on the thermal efficiency \35\ of a boiler. The Joint
Advocates suggested that multiple temperatures (i.e., 108 [deg]F and
158 [deg]F) would be more appropriate to be able to differentiate
amongst different condensing boiler models, and that non-condensing
boilers should be tested at a higher temperature of 158 [deg]F. (Joint
Advocates, No. 21 at p. 2-3)
---------------------------------------------------------------------------

\34\ Appendix 7B of the preliminary analysis TSD is available at
<a href="http://www.regulations.gov">www.regulations.gov</a> at Docket Number EERE-2019-BT-STD-0036. The data
can be found in chapter 7B, page 11.
\35\ Thermal efficiency for a commercial packaged boiler is
determined using test procedures prescribed under 10 CFR 431.86 and
is the ratio of the heat absorbed by the water or the water and
steam to the higher heating value in the fuel burned. Data presented
in the May 2022 Preliminary Analysis TSD reflected the performance
of commercial packaged boilers due to the absence of information on
consumer boilers.
---------------------------------------------------------------------------

Busse stated that the current RWT settings were from NBSIR 80-2110
and asserted that the underlying assumptions for the current return
water temperature found in NBSIR 80-2110, pages 1-2 are out of date or
invalid.\36\ Busse stated that the average distribution system water
temperature in the current DOE test procedure should be closer to 133
[deg]F based on heat load calculations to maintain a home at 65 [deg]F.
Busse noted that the current test procedure has an average distribution
system water temperature of 130 [deg]F (based on a return water
temperature of 120 [deg]F and an outlet temperature of 140 [deg]F).
However, Busse added that the average distribution system water
temperature may be too high based on current or historically available
heat distribution products, and that review literature from two cast-
iron baseboard manufacturers and two finned-tube copper baseboard
manufacturers suggest an average distribution system water temperature
of 127 [deg]F would be more representative. Busse stated that current
industry practice for step-modulating, condensing boilers may not allow
operation at the original 190 [deg]F average boiler water temperature
(200 [deg]F supply) or deliver 140 [deg]F supply temperature at the 42
[deg]F average outdoor temperature at the default controller settings.
(Busse, No. 22 at p. 2-4) Busse recommended that a separate test should
be required for determining heating capacity using a 180 [deg]F return
supply water temperature (or the maximum supply temperature allowed by
the control system, if less than 200 [deg]F), or, alternatively, the
current return water temperature could be used with consideration of
sensible heat losses only in order to estimate the steady-state
efficiency for a noncondensing operation at high return water
temperatures. (Busse, No. 22 at p. 6) Busse also asserted that boilers
with reported ratings of 95 percent or 96 percent AFUE have such
ratings as a result of a flawed calculation in the current test
procedure, which does not account for the portion of the season during
which the boiler would operate in a non-condensing mode (due to return
water temperatures being higher than 120 [deg]F in certain conditions).
(Busse, No. 22 at p. 11-12)
---------------------------------------------------------------------------

\36\ Kelly, George E. and Kuklewicz, Mark E., NBSIR 80-2110:
Recommended Testing and Calculation Procedures for Estimating the
Seasonal Performance of Residential Condensing Furnaces and Boilers,
National Bureau of Standards (Sponsored by U.S. Department of
Energy), April 1981.
---------------------------------------------------------------------------

As acknowledged by commenters, the specification of RWT has a
substantive impact on the AFUE of boilers. Condensing boilers in
particular achieve higher efficiency levels by extracting latent heat
from the flue gases in addition to sensible heat (i.e., the
condensation of flue gases releases a substantial amount of energy into
the water that is being heated). However, flue gases can condense only
if the dew point temperature of the vapor is reached. If the return
(inlet) water is hotter than this dew point temperature, then
condensation of the flue gases cannot occur in the heat exchanger, and
the boiler operates in a non-condensing mode, reducing AFUE.
In addition to the recommendations provided by commenters, DOE
research indicates a range of RWTs in consumer applications. DOE is
aware that many existing consumer boiler installations require the RWT
to be 160 [deg]F and some even as high as 180 [deg]F.\37\ However, as
new applications such as radiant floor heating and heat pump boilers
become more prevalent in the market, DOE recognizes that some new
boilers may be installed in homes that require lower

[[Page 15530]]

RWTs. In addition, condensing boilers in new installations would be
subject to lower RWTs because radiant floor heating and hydronic air
handler applications represent a substantial proportion of new hot
water boiler installations.\38\ DOE research indicates some
installations have RWT conditions as low as 85 [deg]F in certain
cases.\39\ DOE notes that the midpoint of the range of RWTs observed
through DOE's research (ranging between 85 [deg]F and 160 [deg]F) is
122 [deg]F, which is reasonably close to the 120 [deg]F condition
specified in appendix N and the industry test procedures. Given these
considerations, DOE has determined that testing a consumer boiler at a
single ``high'' RWT, as suggested by the Joint Advocates, NYSERDA, and
Busse, would be less representative than the conditions specified by
the current test procedure.
---------------------------------------------------------------------------

\37\ On May 4, 2022, DOE published in the Federal Register a
notice of availability of the preliminary analysis for energy
conservation standards for consumer boilers (the ``May 2022
Preliminary Analysis''). 87 FR 26304. DOE provided a technical
support document (``TSD'') for the May 2022 Preliminary Analysis in
the rulemaking docket. Id. In the energy use analysis of the May
2022 Preliminary Analysis TSD, DOE estimated that 90 percent of
condensing boilers installed as replacements to non-condensing
boilers would be subject to a higher RWT of 158 [deg]F to 160
[deg]F.
\38\ In the May 2022 Preliminary Analysis, DOE estimated that
condensing boilers in new installations (new constructions or new
owners) would be subject to an average RWT of 108 [deg]F. See
Appendix 7B of the preliminary analysis TSD, available at:
<a href="http://www.regulations.gov/document/EERE-2019-BT-STD-0036-0021">www.regulations.gov/document/EERE-2019-BT-STD-0036-0021</a>.
\39\ See, for example: www.barronheating.com/blog/the-book-on-
radiant-heating-when-it-makes-sense-and-when-it-might-not/
#:~:text=Radiant%2Dfloor%20heating%20systems%20typically,55%E2%80%937
0%C2%B0C). (Last accessed on October 6, 2022)
---------------------------------------------------------------------------

DOE also acknowledges the concerns raised by manufacturers
regarding the potential need to retest and recertify all consumer
boilers if a new test condition were to be required in addition to the
currently established 120 [deg]F condition. EPCA requires DOE to
establish test procedures that are reasonably designed to produce test
results that measure energy efficiency of a consumer boiler during a
representative average use cycle or period of use, as determined by the
Secretary, and shall not be unduly burdensome to conduct. (42 U.S.C.
6293(b)(3)) Based on the considerations discussed in this section, DOE
has determined that it lacks data and information to conclude that a
different RWT (or multiple RWTs) would be more representative than the
current RWT requirements such that it would justify the potential
burden of such a change. Hence, in this final rule, DOE is finalizing
its proposal from the March 2022 NOPR to incorporate by reference the
test conditions in ANSI/ASHRAE 103-2017. Should additional data or
information become available in the future, DOE would consider this
topic again in a subsequent test procedure rulemaking.
7. Standby Mode and Off Mode Electrical Energy Consumption
As discussed in section I.A of this final rule, EPCA requires that
DOE amend test procedures to include standby mode and off mode energy
consumption, ``taking into consideration the most current versions of
Standards 62301 and 62087 of the International Electrotechnical
Commission.'' (42 U.S.C. 6295(gg)(2)(A)) The DOE test method currently
references IEC 62301 (Edition 2.0 2011-01), which provides instructions
for measuring standby mode and off mode energy consumption. IEC 62301
provides several options for measuring the standby mode and off mode
power consumption using either the ``sampling method,'' ``average
reading method,'' or ``direct meter reading method.'' Although these
methods vary, if the standby or off mode consumption is stable, each
method can be completed in under 1 hour, and the sampling method can be
completed in as little as 15 minutes.
In the March 2022 NOPR, DOE tentatively determined that the
provisions in IEC 62301 provide an appropriate representation of
standby mode and off mode energy consumption of consumer boilers and
are not unduly burdensome; hence DOE did not propose any changes.
Because commenters responding to the May 2020 RFI recommended
streamlining the procedure for determining standby mode and off mode
energy consumption, in the March 2022 NOPR DOE requested further
comment on whether a simplified approach for measuring standby mode and
off mode electrical energy consumption is appropriate and would provide
accurate, representative results that are comparable to those obtained
with IEC 62301. 87 FR 14622, 14634.
In response, BWC commented that the standby mode and off mode test
methods are appropriate and do not need to be amended at this time.
(BWC, No. 19 at p. 4)
Rheem stated that the current approach for measuring standby and
off mode electrical energy consumption is not overly burdensome and
should be maintained. Rheem also recommended that DOE examine a
combined AFUE metric that includes standby and off mode electrical
energy use, asserting that an increase in standby and off mode energy
use may be needed to accommodate an increase in overall efficiency, and
thus a combined AFUE metric would provide for greater design
flexibility. (Rheem, No. 18 at p. 4)
DOE considered an integrated AFUE metric (``AFUE<INF>I</INF>'') in
a test procedure final rule published October 20, 2010 (``October 2010
Final Rule''), which established the standby mode and off mode
electrical energy use metrics. 75 FR 64621, 64626-64627 (Oct. 20,
2010). In the October 2010 Final Rule, DOE explored the possibility of
regulating AFUE<INF>I</INF>; however, commenters objected that the
approach would provide an ineffective basis for regulation, and thus it
was not ``technically feasible'' to integrate AFUE with standby mode
and off mode energy consumption. Id. Separate metrics were established
because the magnitude of the standby mode and off mode energy
consumption was very small compared to the active mode fuel
consumption, and, as a result, it was not possible to discern different
levels of standby and off mode power consumption (i.e.,
AFUE<INF>I</INF> values were essentially identical to AFUE values). Id.
Neither Rheem nor other commenters have presented DOE with any
information to suggest that the conclusions from the October 2010 Final
Rule--specifically, that an integrated metric would not be technically
feasible--are no longer applicable. Furthermore, DOE is not aware of
any current industry-accepted test procedure that combines the current
AFUE metric with the standby mode and off mode power consumption
metrics. For these reasons, DOE is not adopting any new provisions for
a combined metric in this final rule.
A.O. Smith recommended eliminating the standby mode and off mode
power consumption testing due to the little impact the associated power
consumption has on the total efficiency of a consumer boiler (less than
a fraction of one percent). A.O. Smith indicated that procuring the
adequate equipment and instrumentation required for this testing is
burdensome. A.O. Smith also commented that removing these requirements
would afford manufacturers the opportunity to potentially add safety
enhancements such as carbon monoxide sensors, which require a small
heating element to prevent premature failure, as well as options for
control displays and ways to reduce cycling losses. (A.O. Smith, No. 24
at p. 4) A.O. Smith recommended that if DOE were to keep the standby
mode and off mode tests as part of the test procedure, the standby mode
and off mode power consumption should be measured with a simple current
measurement with a calibrated watt meter. (A.O. Smith, No. 24 at p. 6)
As discussed, EPCA requires that DOE include in its test procedures
a method

[[Page 15531]]

for measuring standby mode and off mode power consumption, unless
technically infeasible. (42 U.S.C. 6295(gg)(2)(A)) Further, in doing
so, EPCA requires that DOE must consider IEC Standard 62301 and IEC
Standard 62087. (42 U.S.C. 6295(gg)(2)(A)) Section 4.4 of IEC 62301
provides instruction on selecting acceptable power measuring
instrumentation by specifying power measurement uncertainty bounds,
frequency response, and long-term averaging (integrating) requirements.
DOE notes that if a calibrated watt meter is capable of meeting these
requirements, then it may be used in accordance with section 4.4 of IEC
62301.
AHRI noted that standby mode and off mode power consumption should
not count as a loss because all energy brought into the system provides
useful resistive heat to the building. AHRI stated that similar logic
is used to give electric boilers a rating of 100 percent efficiency.
(AHRI, No. 26 at p. 3)
While electrical component power draws that dissipate small amounts
of heat to the surroundings may contribute to useful heating to the
building, the building does not always demand heating. During the
cooling season, any heat dissipated would be counterproductive.
Furthermore, not all boilers are located in conditioned spaces. In
addition, as discussed previously, EPCA requires DOE to include in its
test procedures a method for measuring standby mode and off mode power
consumption. (42 U.S.C. 6295(gg)(2)(A)) For these reasons, DOE makes no
change to its inclusion of standby mode and off mode power in this
final rule.
In conclusion, DOE has determined that no changes to the standby
mode and off mode test provisions are warranted. As such, the new
appendix EE test procedure maintains the same test methods for
measuring these metrics as specified in the current appendix N test
procedure.
8. Full Fuel Cycle Efficiency
The full fuel cycle (``FFC'') accounts for the energy consumed in
extracting, processing, and transporting fuels. In the March 2022 NOPR,
DOE responded to comments received in response to the May 2020 RFI
requesting that DOE consider incorporating an FFC analysis into the
test procedure in order to allow for direct comparisons between fossil
fuel-fired systems and electric systems. 87 FR 14622, 14634. DOE
responded that FFC is typically considered in energy conservation
standards rulemakings--not as a metric for representing product
efficiency. Id. In the March 2022 NOPR, DOE maintained its previous
conclusion from the January 2016 Final Rule that a mathematical
adjustment to the test procedure to account for FFC is not appropriate
because the mathematical adjustment to the site-based energy descriptor
relies on information that is updated annually, which would require
annual updating of the test method. Id.
In response to the March 2022 NOPR, BWC stated that the FFC
efficiency and source efficiency analysis are not appropriate to
include in the Federal test procedure. (BWC, No. 19, p. 4)
For the reasons discussed in the March 2022 NOPR, DOE maintains in
this final rule its previous determination not to account for FFC in
the consumer boiler test procedure.
9. Idle Losses
In the March 2022 NOPR, DOE responded to comments received in
response to the May 2020 RFI requesting that DOE consider ``idle
losses'' that are not captured in the AFUE metric. 87 FR 14622, 14628.
Specifically, Energy Kinetics asserted that oversizing of boilers can
lead to wasted energy to heat up the boiler but not contribute to the
heating of the hydronic loop. In the March 2022 NOPR, DOE stated that
EPCA (42 U.S.C. 6295(f)(3)(A)-(B)) requires hot water boilers to have
an automatic means for adjusting water temperature, which limits idle
losses. DOE indicated that idle losses could be further addressed in
the determination of AFUE; however, there was insufficient data to
propose amendments to the test procedure to do so. DOE sought further
comment from interested parties on the topic. 87 FR 14622, 14628.
In response to the March 2022 NOPR, Rheem agreed with DOE's
statement that the prescriptive design requirements in EPCA at 42
U.S.C. 6295(f)(3) effectively reduce idle losses in the field. Rheem
noted that if idle losses, both electrical and fossil fuel, were fully
accounted for in the AFUE metric, then a standard could be proposed
that would not require separate design requirements. (Rheem, No. 18 at
p. 5)
DOE has determined that there remains insufficient information to
further address idle losses in this rulemaking as it pertains to the
determination of AFUE in the new appendix EE test procedure for
consumer boilers.

H. Alternative Efficiency Determination Methods

At 10 CFR 429.70, DOE includes provisions for alternative
efficiency determination methods (``AEDMs''), which are computer
modeling or mathematical tools that predict the performance of non-
tested basic models. They are derived from mathematical models and
engineering principles that govern the energy efficiency and energy
consumption characteristics of a type of covered equipment. These
computer modeling and mathematical tools, when properly developed, can
provide a relatively straight-forward and reasonably accurate means to
predict the energy usage or efficiency characteristics of a basic model
of a given covered product or equipment and reduce the burden and cost
associated with testing. 78 FR 79579, 79580 (Dec. 31, 2013; the
``December 2013 AEDM Final Rule''). Where authorized by regulation,
AEDMs enable manufacturers to rate and certify their basic models by
using the projected energy use or energy efficiency results derived
from these simulation models in lieu of testing. Id. at 78 FR 79580.
DOE does not currently authorize the use of AEDMs for consumer
boilers, whereas DOE does authorize the use of AEDMs for commercial
packaged boilers.\40\ Manufacturers of consumer boilers (or furnaces
more generally) are not authorized to use an AEDM to determine ratings
for these products. However, manufacturers of cast-iron boilers may
determine AFUE for models at a capacity other than the highest or
lowest of the group of basic models having identical intermediate
sections and combustion chambers through linear interpolation of data
obtained for the smallest and largest capacity units of the family. See
10 CFR 429.18(a)(2)(iv)(A). These provisions already provide
manufacturers with an alternative method of rating consumer boilers
without testing every model, and this alternative method reduces
manufacturer test burden.
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\40\ In the December 2013 AEDM Final Rule, DOE explained that
the AEDM provisions extend to those products or equipment which
``have expensive or highly-customized basic models.'' 78 FR 79579,
79580. The current AEDM provisions for commercial HVAC equipment
(including commercial package boilers, for example) were in part the
result of a negotiated rulemaking effort by the Appliance Standards
and Rulemaking Federal Advisory Committee (ASRAC) in 2013. Id.
Boilers designed for residential applications were not considered at
the time. 78 FR 79579.
---------------------------------------------------------------------------

In the March 2022 NOPR, DOE requested comment on whether AEDM
provisions similar to those in place for commercial equipment would be
necessary and appropriate for consumer boilers. 87 FR 14622, 14635.
A.O. Smith stated that adding an AEDM option for consumer boilers
would be reasonable; however, there is

[[Page 15532]]

greater value to have an AEDM for commercial products given that those
models can be engineered to order. (A.O. Smith, No. 24 at p. 4) Busse
indicated that the breadth of a product line with similar geometries
and performance would not seem to justify an AEDM; however, an AEDM may
be the only method to avoid testing each model. (Busse, No. 22 at p. 8)
In consideration of these comments, as well as considerations
discussed in the March 2022 NOPR (see 87 FR 14622, 14635), in this
final rule, DOE concludes that manufacturer testing burden is
alleviated by the linear interpolation provisions for cast-iron
boilers, such that an AEDM for consumer boilers more broadly is not
warranted at this time.

I. Certification Provisions for Cast-Iron Boilers

As discussed in the March 2022 NOPR, the certification provisions
at 10 CFR 429.18(a)(2)(iv)(A) alleviate testing burden for cast-iron
boilers, which are commonly constructed of identical cast-iron heat
exchanger sections. Boilers of the same cast-iron product family are
often constructed so that the heating capacity can be increased by
adding more sections to the heat exchanger. When a product family is
designed in this way, linear interpolation is accurate \41\ to predict
the performance of intermediately-sized boilers. The March 2022 NOPR
sought data and other information that would demonstrate that using a
linear interpolation method for heat exchanger materials other than
cast-iron would produce representative test results. 87 FR 14622,
14635.
---------------------------------------------------------------------------

\41\ Test data analyzed as part of the 1979 rulemaking which
established these provisions showed that the annual fuel utilization
efficiency, energy consumption, and estimated annual operating cost
of sectional cast-iron boilers can be accurately predicted by a
linear interpolation based on data obtained from units having the
smallest and largest number of intermediate sections. 44 FR 22410,
22415 (April 13, 1979).
---------------------------------------------------------------------------

AHRI and AGA and APGA supported extending of the use of linear
interpolation to heat exchanger materials other than cast-iron, stating
that linear interpolation is a valid calculation method for these
products, as proven by the current cast-iron allowance. (AHRI, No. 26
at p. 4; AGA and APGA, No. 25 at p. 2)
A.O. Smith supported use of the interpolation method for boilers
with heat exchangers other than cast-iron, stating that its copper
finned-tube boilers have a tray of tubes that increase in length
proportionate to input rate, are consistent in geometry, and have only
incremental changes proportionate to input rate. A.O. Smith added that
its Lochinvar brand models have seven input rates ranging from 45,000
Btu/h through 260,000 Btu/h and all perform near 84.0-percent AFUE.
(A.O. Smith, No. 24 at p. 5)
Rheem did not support the use of linear interpolation for
certification of consumer boilers beyond what is already allowed for
cast-iron boilers, stating that interpolation produces less accurate
results than results derived from actual tests. (Rheem, No. 18 at p. 4)
Busse did not support using a linear interpolation method for heat
exchanger materials other than cast-iron. Busse asserted that any
difference and/or non-proportionality in excess air, flue loading, and/
or flue cross-sectional area could produce non-linear results, which is
also why cast-iron units equipped with draft hoods, draft diverters, or
induced draft systems are more prone to producing non-linear results.
(Busse, No. 22 at p. 7-8)
Based on DOE's review of product literature, DOE has determined
that heat exchangers made of different materials may not be constructed
with identical additive components the way cast-iron sectional heat
exchangers are constructed; hence, the linear interpolation method may
be less viable for other heat exchanger materials. DOE notes that
stakeholders commenting in support of using linear interpolation for
materials other than cast-iron did not provide any data to demonstrate
the viability of a linear interpolation method for other heat exchanger
materials. Given the concerns raised by Rheem and Busse regarding the
potential for non-linear results for intermediately-sized boilers with
non-cast-iron heat exchangers, as well as DOE's review of product
literature, DOE has concluded that there is not enough information to
substantiate such a provision at this time. Hence, in this final rule,
DOE maintains that the linear interpolation AEDM method applies only to
cast-iron boilers.
Additionally, Busse recommended the following clarifications for
using linear interpolation: (1) clarify if interpolated values are
derived from truncated or pre-truncated AFUE values of smallest and
largest capacity units, (2) update 10 CFR part 429 to allow
interpolation of heating capacity derived from unrounded
Effy<INF>SS</INF> values of smallest and largest capacity units, and
(3) require third-party test agencies to qualify AFUE and heating
capacity on an ``interpolated'' model. (Busse, No. 22 at p. 7-8)
First, as discussed in section III.F.8, DOE has amended the
certification requirements for AFUE in the July 2022 Certification
Final Rule to require that AFUE must be rounded to the nearest tenth of
a percentage point when this value is reported. 87 FR 43968. Thus, as
of this final rule, truncation is no longer used to report AFUE. DOE is
clarifying in this final rule, however, that manufacturers may use
either the rounded or unrounded AFUE values of the smallest and largest
capacity units for linear interpolation. DOE is making this
determination based on the fact that the results of the linear
interpolation would be minimally impacted by rounding AFUE to the
nearest tenth of a percentage point, compared to using unrounded
values.
Second, DOE notes that heating capacity (Q<INF>OUT</INF>), which is
calculated in the current test procedure as a function of steady-state
efficiency (Effy<INF>SS</INF>), is not required to be certified to DOE
at this time, nor has DOE proposed to make this a requirement.
Currently, manufacturers must certify the nameplate input rate
(Q<INF>IN</INF>), which is a separate metric and not a function of
Effy<INF>SS</INF>. Hence, DOE is not updating the linear interpolation
provisions to include heating capacity (Q<INF>OUT</INF>).
Third, requiring third-party testing to qualify AFUE ratings
derived using the linear interpolation method would eliminate the
reduction in test burden achieved with the alternate linear
interpolation approach. DOE notes, however, that it can conduct
assessment or enforcement testing on consumer boiler models, and this
process serves to verify ratings (see subpart C to 10 CFR part 429).
In conclusion, DOE has determined in this final rule not to amend
the linear interpolation provisions for consumer boilers.

J. Effective and Compliance Dates

The effective date for the adopted test procedure amendment will be
30 days after publication of this final rule in the Federal Register.
EPCA prescribes that all representations of energy efficiency and
energy use, including those made on marketing materials and product
labels, must be made in accordance with an amended test procedure,
beginning 180 days after publication of the final rule in the Federal
Register. (42 U.S.C. 6293(copyright)(2)) EPCA provides an allowance for
individual manufacturers to petition DOE for an extension of the 180-
day period if the manufacturer may experience undue hardship in meeting
the deadline. (42 U.S.C. 6293(c)(3)) To receive such an extension,
petitions must be filed with DOE no later than 60 days before the end
of the 180-day period and must detail how the

[[Page 15533]]

manufacturer will experience undue hardship. (Id.)

K. Test Procedure Costs

EPCA requires that test procedures proposed by DOE not be unduly
burdensome to conduct. (42 U.S.C. 6293(b)(3))
In the March 2022 NOPR, DOE discussed that the amendments proposed
to the test procedure for consumer boilers would be expected to have
minimal impact on efficiency ratings such that manufacturers would not
be required to retest and recertify ratings. 87 FR 14622, 14625, 14636.
DOE also tentatively determined that the proposed amendments would not
impact testing costs or increase burden. DOE requested feedback from
stakeholders on these tentative determinations. Id.
A.O. Smith supported DOE's determination that the proposed
incorporation by reference of ASHRAE 41.6-2014 will not increase
testing burden. A.O. Smith also stated that DOE's estimate for third-
party AFUE testing is reasonable and agreed that the proposed
incorporation by reference of ANSI/ASHRAE 103-2017 is not unduly
burdensome. (A.O. Smith, No. 24 at p. 5) A.O. Smith stated that
although there may be fractional changes in the AFUE rating as a result
of testing to the 2017 version, these should not necessitate retesting
or rerating of any existing boilers. A.O. Smith also supported having a
publicly available AFUE calculation tool to enhance consistency of
results across the industry. (A.O. Smith, No. 24 at p. 3)
Rheem stated that the test costs under the proposed appendix EE
test procedure are likely to remain similar to the current appendix N
test procedure. (Rheem, No. 18 at p. 5)
AHRI stated that it previously commented that a move to ANSI/ASHRAE
103-2017 would not result in increased test burden; however, it had
come to AHRI's attention that there are manufacturers using automated
programs that would incur an increased test burden. (AHRI, No. 26 at p.
4)
DOE understands that AHRI is referring to pre-programmed cycle
times, which execute burner on and off functions at pre-determined
times per the DOE test procedure. From DOE's own testing of the impact
of cycle timings at a third-party lab using an automated program, DOE
has determined that these parameters can be simple to re-program and
that doing so would not constitute undue test burden. As discussed in
section III.D.1.c, other commenters requested DOE to further
investigate whether the update in cycle times would increase burden by
requiring retesting. Based on test data indicating little variation in
test results due to the update in cycle times, DOE has determined that
the impact of these amendments on ratings would be minimal. With regard
to providing a publicly available AFUE calculation tool, DOE provides
test report templates on its certification website,\42\ including a
template for the consumer boiler test procedure.
---------------------------------------------------------------------------

\42\ Standardized test report templates are available online at:
<a href="http://www.energy.gov/eere/buildings/standardized-templates-reporting-test-results">www.energy.gov/eere/buildings/standardized-templates-reporting-test-results</a>.
---------------------------------------------------------------------------

For this final rule, DOE has evaluated the impacts on ratings
resulting from its adoption of the test methods in the updated industry
test standard, ANSI/ASHRAE 103-2017. These updates are discussed in
detail in section III.D.1 of this final rule. Based on this review, DOE
has determined that manufacturers will be able to rely on data
generated under the current test procedure. As such, it is unlikely
that retesting of consumer boilers would be required solely as a result
of DOE's adoption of the finalized amendments to the test procedure.
However, if a manufacturer were to retest a model using the amended
test procedure as finalized, DOE estimates that the cost of performing
the amended AFUE test at a third-party laboratory would be $3,600, the
same as the cost of performing the current AFUE test. This estimate
represents an increase of $600 from the cost estimate in the March 2022
NOPR, to account for overall increases in laboratory testing fees.

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Orders 12866 and 13563

Executive Order (``E.O.'') 12866, ``Regulatory Planning and
Review,'' as supplemented and reaffirmed by E.O. 13563, ``Improving
Regulation and Regulatory Review,'' 76 FR 3821 (Jan. 21, 2011),
requires agencies, to the extent permitted by law, to (1) propose or
adopt a regulation only upon a reasoned determination that its benefits
justify its costs (recognizing that some benefits and costs are
difficult to quantify); (2) tailor regulations to impose the least
burden on society, consistent with obtaining regulatory objectives,
taking into account, among other things, and to the extent practicable,
the costs of cumulative regulations; (3) select, in choosing among
alternative regulatory approaches, those approaches that maximize net
benefits (including potential economic, environmental, public health
and safety, and other advantages; distributive impacts; and equity);
(4) to the extent feasible, specify performance objectives, rather than
specifying the behavior or manner of compliance that regulated entities
must adopt; and (5) identify and assess available alternatives to
direct regulation, including providing economic incentives to encourage
the desired behavior, such as user fees or marketable permits, or
providing information upon which choices can be made by the public. DOE
emphasizes as well that E.O. 13563 requires agencies to use the best
available techniques to quantify anticipated present and future
benefits and costs as accurately as possible. In its guidance, the
Office of Information and Regulatory Affairs (``OIRA'') in the Office
of Management and Budget (``OMB'') has emphasized that such techniques
may include identifying changing future compliance costs that might
result from technological innovation or anticipated behavioral changes.
For the reasons stated in the preamble, this final regulatory action is
consistent with these principles.
Section 6(a) of E.O. 12866 also requires agencies to submit
``significant regulatory actions'' to OIRA for review. OIRA has
determined that this final regulatory action does not constitute a
``significant regulatory action'' under section 3(f) of E.O. 12866.
Accordingly, this action was not submitted to OIRA for review under
E.O. 12866.

B. Review Under the Regulatory Flexibility Act

The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires
preparation of a final regulatory flexibility analysis (FRFA) for any
final rule where the agency was first required by law to publish a
proposed rule for public comment, unless the agency certifies that the
rule, if promulgated, will not have a significant economic impact on a
substantial number of small entities. As required by Executive Order
13272, ``Proper Consideration of Small Entities in Agency Rulemaking,''
67 FR 53461 (August 16, 2002), DOE published procedures and policies on
February 19, 2003, to ensure that the potential impacts of its rules on
small entities are properly considered during the DOE rulemaking
process. 68 FR 7990. DOE has made its procedures and policies available
on the Office of the General Counsel's website: <a href="http://www.energy.gov/gc/office-general-counsel">www.energy.gov/gc/office-general-counsel</a>.
DOE reviewed this final rule under the provisions of the Regulatory
Flexibility Act and the procedures and policies published on February
19,

[[Page 15534]]

2003. DOE certifies that this rule, if adopted, would not have
significant economic impact on a substantial number of small entities.
The factual basis of this certification is set forth below.
Under 42 U.S.C. 6293, EPCA sets forth the criteria and procedures
DOE must follow when prescribing or amending test procedures for
covered products. EPCA requires that any test procedures prescribed or
amended under this section shall be reasonably designed to produce test
results which measure energy efficiency, energy use, or estimated
annual operating cost of a covered product during a representative
average use cycle (as determined by the Secretary) or period of use and
shall not be unduly burdensome to conduct. (42 U.S.C. 6293(b)(3))
EPCA also requires that, at least once every 7 years, DOE evaluate
test procedures for each type of covered product, including consumer
boilers, to determine whether amended test procedures would more
accurately or fully comply with the requirements for the test
procedures to not be unduly burdensome to conduct and be reasonably
designed to produce test results that reflect energy efficiency, energy
use, and estimated operating costs during a representative average use
cycle or period of use. (42 U.S.C. 6293(b)(1)(A)) DOE is publishing
this final rule in satisfaction of the 7-year review requirement
specified in EPCA. (42 U.S.C. 6293(b)(1)(A))
DOE did not receive written comments that specifically addressed
impacts on small businesses or that were provided in response to the
March 2022 NOPR.
The Small Business Administration (``SBA'') has set a size
threshold, which defines those entities classified as ``small
businesses'' for the purposes of the statute. DOE used the SBA's small
business size standards to determine whether any small entities would
be subject to the requirements of the rule. See 13 CFR part 121. The
products covered by this rule are classified under North American
Industry Classification System (``NAICS'') code 333414,\43\ ``Heating
Equipment (except Warm Air Furnaces) Manufacturing.'' In 13 CFR
121.201, the SBA sets a threshold of 500 employees or fewer for an
entity to be considered as a small business for this category. This
employment figure is enterprise-wide, encompassing employees at the
parent, subsidiary, and sister corporations.
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\43\ The SBA size standards (effective October 1, 2022) are
listed by NAICS code and industry description and are available at:
<a href="http://www.sba.gov/document/support-table-size-standards">www.sba.gov/document/support-table-size-standards</a> (last accessed on
December 1, 2022).
---------------------------------------------------------------------------

Consistent with the March 2022 NOPR, DOE relied on the Compliance
Certification Database (``CCD''),\44\ the AHRI database,\45\ the
California Energy Commission's Modernized Appliance Efficiency Database
System (``MAEDbS''),\46\ the ENERGY STAR Product Finder database,\47\
and the prior consumer boiler energy conservation standards rulemaking
to create a list of companies that import or otherwise manufacture the
products covered by this final rule. DOE used the publicly available
information and subscription-based market research tools (e.g., reports
from Dun & Bradstreet \48\) to identify 27 original equipment
manufacturers (``OEMs'') affected by this final rule. Of the 27 OEMs,
DOE identified five domestic OEMs of consumer boilers that met the SBA
definition of a ``small business'' and are not foreign-owned and
operated.
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\44\ U.S. Department of Energy Compliance Certification
Database, available at: <a href="http://www.regulations.doe.gov/certification-data/products.html">www.regulations.doe.gov/certification-data/products.html</a>.
\45\ The AHRI Database is available at: <a href="http://www.ahridirectory.org">www.ahridirectory.org</a>
(last accessed March 3, 2021).
\46\ California Energy Commission's MAEDbS is available at
<a href="http://cacertappliances.energy.ca.gov/Pages/ApplianceSearch.aspx">cacertappliances.energy.ca.gov/Pages/ApplianceSearch.aspx</a> (last
accessed September 22, 2021).
\47\ The ENERGY STAR Product Finder database is available at
<a href="http://energystar.gov/productfinder/">energystar.gov/productfinder/</a> (last accessed September 22, 2021).
\48\ D&B Hoovers [verbar] Company Information [verbar] Industry
Information [verbar] Lists, <a href="http://app.dnbhoovers.com/">app.dnbhoovers.com/</a> (last accessed
September 29, 2022).
---------------------------------------------------------------------------

In this final rule, DOE updates appendix N to remove the provisions
applicable only to consumer boilers and to rename the current appendix
as ``Uniform Test Method for Measuring the Energy Consumption of
Furnaces.'' Correspondingly, this final rule establishes a new test
procedure at 10 CFR part 430 subpart B, appendix EE, ``Uniform Test
Method for Measuring the Energy Consumption of Boilers'' (``appendix
EE''). In the new appendix EE, DOE includes all provisions currently
included in appendix N relevant to consumer boilers, with the following
modifications:
(1) Incorporate by reference the current revision to the applicable
industry standard, ANSI/ASHRAE 103-2017, ``Methods of Testing for
Annual Fuel Utilization Efficiency of Residential Central Furnaces and
Boilers.''
(2) Incorporate by reference the current revision of ASTM Standard
D2156-09 (Reapproved 2018), ``Standard Test Method for Smoke Density in
Flue Gases from Burning Distillate Fuels.''
(3) Incorporate by reference ANSI/ASHRAE 41.6-2014, ``Standard
Method for Humidity Measurement.''
(4) Update the definitions to reflect the changes in ANSI/ASHRAE
103-2017 as compared to ANSI/ASHRAE 103-1993.
(5) Provide corrections to erroneous calculations and add
clarifications to test conditions and setup requirements.
DOE is also removing the definition of outdoor furnace or boiler
from 10 CFR 430.2.
DOE has determined that the amendments adopted in this final rule
will not substantively impact the measured efficiency of consumer
boilers or require retesting or recertification solely as a result of
DOE's adoption of the amendments to the test procedures. As outlined in
Table II.1 of this final rule, the new appendix EE includes all
provisions currently included in appendix N relevant to consumer
boilers, with modifications to: harmonize with industry standard
updates; provide corrections to erroneous calculations; and add
clarifications to test conditions and setup requirements. Additionally,
the update to use more representative cycle timings and oversize
factors in the new appendix EE test procedure was demonstrated to have
minimal impact on AFUE ratings as a result of testing. See section
III.K of this final rule for additional details on test procedure
costs. DOE also determined that the amendments would not increase the
testing costs or burden associated with the DOE test procedure for
consumer boilers, as the cost to test consumer boilers under the
amended test procedure is $3,600, the same as the cost to test consumer
boilers under the existing test procedure.
Therefore, DOE concludes that the cost effects accruing from the
final rule would not have a ``significant economic impact on a
substantial number of small entities,'' and that the preparation of a
FRFA is not warranted.

C. Review Under the Paperwork Reduction Act of 1995

Manufacturers of consumer boilers must certify to DOE that their
products comply with any applicable energy conservation standards. To
certify compliance, manufacturers must first obtain test data for their
products according to the DOE test procedures, including any amendments
adopted for those test procedures. DOE has established regulations for
the certification and recordkeeping requirements for all covered
consumer products and commercial equipment, including consumer boilers.
(See

[[Page 15535]]

generally 10 CFR part 429.) The collection-of-information requirement
for the certification and recordkeeping is subject to review and
approval by OMB under the Paperwork Reduction Act (PRA). This
requirement has been approved by OMB under OMB control number 1910-
1400. Public reporting burden for the certification is estimated to
average 35 hours per response, including the time for reviewing
instructions, searching existing data sources, gathering and
maintaining the data needed, and completing and reviewing the
collection of information.
DOE is not amending the certification or reporting requirements for
consumer boilers in this final rule.
Notwithstanding any other provision of the law, no person is
required to respond to, nor shall any person be subject to a penalty
for failure to comply with, a collection of information subject to the
requirements of the PRA, unless that collection of information displays
a currently valid OMB Control Number.

D. Review Under the National Environmental Policy Act of 1969

In this final rule, DOE establishes test procedure amendments that
it expects will be used to develop and implement future energy
conservation standards for consumer boilers. DOE has determined that
this rule falls into a class of actions that are categorically excluded
from review under the National Environmental Policy Act of 1969 (42
U.S.C. 4321 et seq.) and DOE's implementing regulations at 10 CFR part
1021. Specifically, DOE has determined that adopting test procedures
for measu

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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.