30796 Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 

determined that the proposed revisions 

did not sufficiently justify the impact on 

the estimated 1.7 million SNAP 

households that would have lost 

eligibility under the rule and did not 

adequately mitigate the disproportionate 

impact the rule would have had on 

households with an elderly member. 

Additionally, the Deparment has 

determined that the proposed changes 

and concerns raised regarding program 

integrity were not adequately supported 

by data and do not justify the costs to 

State agencies of implementing the 

change. 

In withdrawing this proposed rule, 

the Department reaffirms the purpose of 

categorical eligibility to simplify the 

SNAP application process for both 

SNAP State agencies and households by 

reducing the amount of information that 

must be verified if a household has 

already been determined eligible to 

receive benefits from another assistance 

program specified in Sec. 5(a) of the 

Act. Beginning in 2009, the Department 

proactively encouraged States to 

implement expanded categorical 

eligibility policies in order to increase 

SNAP participation and reduce State 

administrative burdens. The Department 

acknowledges that the flexibility 

afforded by expanded categorical 

eligibility policies are critical to 

reducing the burden on needy 

households and State agencies 

administering benefit programs. 

The Department agrees with the 

issues raised by many commenters and 

no longer believes that the limitations 

the proposed rule would have put on 

categorical eligibility are appropriate. 

Accordingly, the proposed rule to revise 

categorical eligibility for SNAP 

published in the Federal Register on 

July 24, 2019, (84 FR 35570) is hereby 

withdrawn. 

Cynthia Long, 

Acting Administrator, Food and Nutrition 

Service. 

[FR Doc. 2021–12183 Filed 6–9–21; 8:45 am] 

BILLING CODE 3410–30–P 

DEPARTMENT OF ENERGY 

10 CFR Part 431 

[EERE–2017–BT–STD–0021] 

RIN 1904–AD90 

Energy Conservation Program: Energy 

Conservation Standards for Unfired 

Hot Water Storage Tanks 

AGENCY: Office of Energy Efficiency and 

Renewable Energy, Department of 

Energy. 

ACTION: Notification of proposed 

determination and request for comment. 

SUMMARY: The Energy Policy and 

Conservation Act, as amended (EPCA), 

prescribes energy conservation 

standards for various consumer 

products and certain commercial and 

industrial equipment, including unfired 

hot water storage tanks (UFHWSTs). 

EPCA also requires the U.S. Department 

of Energy (DOE or the Department) to 

periodically determine whether morestringent, amended standards would 

result in significant additional 

conservation of energy, be 

technologically feasible, and be 

economically justified. After carefully 

considering the available market and 

technical information for this 

equipment, DOE has tentatively 

concluded in this document that it lacks 

clear and convincing evidence that 

more-stringent standards for UFHWSTs 

would save a significant additional 

amount of energy and would be 

economically justified. As such, DOE 

has initially determined that energy 

conservation standards for UFHWSTs 

do not need to be amended. DOE 

requests comment on this notification of 

proposed determination (NOPD), as well 

as the associated analyses and results. 

DATES: Meeting: DOE will hold a 

webinar on Tuesday, July 13, 2021, from 

12:00 p.m. to 4:00 p.m. See section VII, 

‘‘Public Participation,’’ for webinar 

registration information, participant 

instructions, and information about the 

capabilities available to webinar 

participants. 

Comments: Written comments and 

information are requested and will be 

accepted on or before August 9, 2021. 

ADDRESSES: Interested persons are 

encouraged to submit comments using 

the Federal eRulemaking Portal at 

https://www.regulations.gov. Follow the 

instructions for submitting comments. 

Alternatively, interested persons may 

submit comments by email to the 

following address: 

UnfiredCommercialWH2017STD0021@

ee.doe.gov. Include docket number 

EERE–2017–BT–STD–0021 and/or RIN 

number 1904–AD90 in the subject line 

of the message. Submit electric 

comments in WordPerfect, Microsoft 

Word, PDF, or ASCII file format, and 

avoid the use of special characters or 

any form of encryption. No 

telefacsimiles (faxes) will be accepted. 

For detailed instructions on submitting 

comments and additional information 

on this process, see section VII (Public 

Participation) of this document. 

Although DOE has routinely accepted 

public comment submissions through a 

variety of mechanisms, including postal 

mail and hand delivery/courier, the 

Department has found it necessary to 

make temporary modifications to the 

comment submission process in light of 

the ongoing Covid-19 pandemic. DOE is 

currently accepting only electronic 

submissions at this time. If a commenter 

finds this change poses an undue 

hardship, please contact Appliance 

Standards Program staff at (202) 586– 

1445 to discuss the need for alternative 

arrangements. Once the Covid-19 

pandemic health emergency is resolved, 

DOE anticipates resuming all of its 

regular options for public comment 

submissions, including postal mail and 

hand delivery/courier. 

Docket: The docket for this activity, 

which includes Federal Register 

notices, public meeting attendee lists 

and transcripts, comments, and other 

supporting documents/materials, is 

available for review at https://

www.regulations.gov. All documents in 

the docket are listed in the https://

www.regulations.gov index. However, 

some documents listed in the index, 

such as information that is exempt from 

public disclosure, may not be publicly 

available. 

The docket web page can be found at: 

https://www.regulations.gov/ 

docket?D=EERE-2017-BT-STD-0021. 

The docket web page contains 

instructions on how to access all 

documents, including public comments, 

in the docket. See section VII, ‘‘Public 

Participation,’’ for further information 

on how to submit comments through 

https://www.regulations.gov. 

FOR FURTHER INFORMATION CONTACT: Ms. 

Catherine Rivest, U.S. Department of 

Energy, Office of Energy Efficiency and 

Renewable Energy, Building 

Technologies Office, EE–5B, 1000 

Independence Avenue SW, Washington, 

DC 20585- 0121. Telephone: (202) 586– 

7335. Email: 

ApplianceStandardsQuestions@

ee.doe.gov. 

Mr. Eric Stas, U.S. Department of 

Energy, Office of the General Counsel, 

GC–33, 1000 Independence Avenue SW, 

Washington, DC 20585–0121. 

Telephone: (202) 586-5827. Email: 

Eric.Stas@hq.doe.gov. 

For further information on how to 

submit a comment or review other 

public comments and the docket, 

contact the Appliance and Equipment 

Standards Program staff at (202) 287– 

1445 or by email: 

ApplianceStandardsQuestions@

ee.doe.gov. 

SUPPLEMENTARY INFORMATION: 

Table of Contents 

I. Synopsis of the Proposed Determination 


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1For editorial reasons, upon codification in the 

U.S. Code, Part C was redesignated Part A–1. 

2All 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). 

II. Introduction 

A. Authority 

B. Background 

1. Current Standards 

2. History of Standards Rulemakings for 

UFHWSTs 

III. General Discussion 

A. Product Classes and Scope of Coverage 

B. Test Procedure 

C. Technological Feasibility 

1. General 

2. Maximum Technologically Feasible 

Levels 

D. Energy Savings 

1. Determination of Savings 

2. Significance of Savings 

E. Economic Justification 

1. Specific Criteria 

a. Economic Impact on Manufacturers and 

Consumers 

b. Savings in Operating Costs Compared to 

Increase in Price (LCC and PBP) 

c. Energy Savings 

d. Lessening of Utility or Performance of 

Equipment 

e. Impact of Any Lessening of Competition 

f. Need for National Energy Conservation 

g. Other Factors 

IV. Methodology and Discussion of Related 

Comments 

A. Market and Technology Assessment 

1. Scope of Coverage and Equipment 

Classes 

2. Technology Options 

3. Screening Analysis 

a. Screened-Out Technologies 

b. Remaining Technologies 

B. Engineering Analysis 

1. Efficiency Levels for Analysis 

2. Representative Equipment for Analysis 

3. Cost Analysis 

C. Energy Use Analysis 

1. Tank Thermal Loss Model 

a. Tank Surface Area (Ai, j) 

b. Tank Internal Water Temperature (Ti) 

c. Tank Ambient Temperature (Tamb, z) 

d. R-value of Insulation (Ri, j) 

2. Annual Energy Use Due To UFHWST 

Losses 

3. Additional Sources of Uncertainty 

D. Life-Cycle Cost and Payback Period 

Analysis 

1. Installation Costs 

2. Annual Energy Consumption 

E. Shipments Analysis 

1. Stock Estimates 

a. Residential Stock 

b. Commercial Stock 

c. Industrial Stock 

2. Shipments for Replacement 

3. Shipments for New Construction 

4. Estimated Shipments 

a. Distribution of Shipments by UFHWST 

Storage Volume 

5. Additional Sources of Uncertainty 

F. National Impact Analysis 

1. Energy Efficiency Distribution in the NoNew-Standards Case 

2. Hot Water Supply Boiler Efficiency 

Trend 

G. Discussion of Other Comments Received 

V. Analytical Results and Conclusions 

A. National Impact Analysis 

1. Significance of Energy Savings 

2. Net Present Value of Consumer Costs 

and Benefits 

B. Proposed Determination 

1. Technological Feasibility 

2. Significant Conservation of Energy 

3. Economic Justification 

4. Summary 

VI. Procedural Issues and Regulatory Review 

A. Review Under Executive Order 12866 

B. Review Under the Regulatory Flexibility 

Act 

C. Review Under the Paperwork Reduction 

Act 

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 the Treasury and General 

Government Appropriations Act, 2001 

K. Review Under Executive Order 13211 

L. Review Under the Information Quality 

Bulletin for Peer Review 

VII. Public Participation 

A. Participation in the Webinar 

D. Submission of Comments 

E. Issues on Which DOE Seeks Comment 

VIII. Approval of the Office of the Secretary 

I. Synopsis of the Proposed 

Determination 

Title III, Part C1 of EPCA,2 established 

the Energy Conservation Program for 

Certain Industrial Equipment. (42 U.S.C. 

6311–6317) This equipment includes 

UFHWSTs, the subject of this NOPD. 

(42 U.S.C. 6311(1)(K)) 

Pursuant to EPCA, DOE is triggered to 

consider amending the energy efficiency 

standards for certain types of 

commercial and industrial equipment, 

including the equipment at issue in this 

document, whenever the American 

Society of Heating, Refrigerating, and 

Air-Conditioning Engineers (ASHRAE) 

amends the standard levels or design 

requirements prescribed in ASHRAE 

Standard 90.1, ‘‘Energy Standard for 

Buildings Except Low-Rise Residential 

Buildings,’’ (ASHRAE Standard 90.1). 

Under a separate provision of EPCA, 

DOE is required to review the existing 

energy conservation standards for those 

types of covered equipment subject to 

ASHRAE Standard 90.1 every six 6 

years to determine whether those 

standards need to be amended. (42 

U.S.C. 6313(a)(6)(A)–(C)) DOE is 

conducting this review of the energy 

conservation standards for UFHWSTs 

under EPCA’s six-year-lookback 

authority. (42 U.S.C. 6313(a)(6)(C)) 

For this proposed determination, DOE 

analyzed UFHWSTs subject to standards 

as specified in the Code of Federal 

Regulations (CFR) at 10 CFR 431.110. 

DOE first analyzed the technological 

feasibility of more efficient UFHWSTs. 

For those UFHWSTs for which DOE 

determined higher standards to be 

technologically feasible, DOE estimated 

energy savings that would result from 

potential amended energy conservation 

standards. DOE also considered whether 

potential energy conservation standards 

would be economically justified. As 

discussed in the following sections, 

DOE has initially determined that it 

lacks clear and convincing evidence that 

amended energy conservation standards 

for UFHWSTs would result in 

significant additional conservation of 

energy or be economically justified. 

Based on the results of these analyses, 

summarized in section V of this 

document, DOE has tentatively 

determined that current energy 

conservation standards for UFHWSTs 

do not need to be amended. 

II. Introduction 

The following section briefly 

discusses the statutory authority 

underlying this proposed determination, 

as well as some of the historical 

background relevant to the 

establishment of energy conservation 

standards for UFHWSTs. 

A. Authority 

EPCA, Public Law 94–163 (42 U.S.C. 

6291–6317, as codified), among other 

things, authorizes DOE to regulate the 

energy efficiency of a number of 

consumer products and certain 

industrial equipment. Title III, Part C of 

EPCA, added by Public Law 95–619, 

Title IV, § 441(a) (42 U.S.C. 6311–6317, 

as codified), established the Energy 

Conservation Program for Certain 

Industrial Equipment, which sets forth a 

variety of provisions designed to 

improve energy efficiency. This 

equipment includes UFHWSTs, the 

subject of this document. (42 U.S.C. 

6311(1)(K)) 

Under EPCA, the energy conservation 

program consists essentially of four 

parts: (1) Testing; (2) labeling; (3) the 

establishment of Federal energy 

conservation standards, and (4) 

certification and enforcement 

procedures. Relevant provisions of 

EPCA specifically include definitions 

(42 U.S.C. 6311), energy conservation 

standards (42 U.S.C. 6313), test 

procedures (42 U.S.C. 6314), labeling 

provisions (42 U.S.C. 6315), and the 

authority to require information and 

reports from manufacturers (42 U.S.C. 

6316). 

Federal energy conservation 

requirements for covered equipment 

established under EPCA generally 


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supersede State laws and regulations 

concerning energy conservation testing, 

labeling, and standards. (42 U.S.C. 

6316(a) and (b); 42 U.S.C. 6297) DOE 

may, however, grant waivers of Federal 

preemption in limited circumstances for 

particular State laws or regulations, in 

accordance with the procedures and 

other provisions set forth under EPCA. 

(42 U.S.C. 6297(d); 42 U.S.C. 6316(a); 42 

U.S.C. 6316(b)(2)(D)) 

Subject to certain criteria and 

conditions, DOE is required to develop 

test procedures to measure the energy 

efficiency, energy use, or estimated 

annual operating cost of covered 

equipment. (42 U.S.C. 6314) 

Specifically, EPCA requires that if a test 

procedure referenced in ASHRAE 

Standard 90.1 is updated, DOE must 

update its test procedure to be 

consistent with the amended test 

procedure in ASHRAE Standard 90.1, 

unless DOE determines, by rule, 

published in the Federal Register and 

supported by clear and convincing 

evidence, that the amended test 

procedure is not reasonably designed to 

produce test results that reflect the 

energy efficiency, energy use, or 

estimated operating costs of the covered 

ASHRAE equipment during a 

representative average use cycle. In 

addition, DOE must determine that the 

amended test procedure is not unduly 

burdensome to conduct. (42 U.S.C. 

6314(a)(2) and (4)) In addition, if DOE 

determines that a test procedure 

amendment is warranted, it must 

publish proposed test procedures in the 

Federal Register and offer the public an 

opportunity (of not less than 45 days 

duration) to present oral and written 

comments on them. (42 U.S.C. 6314(b)) 

In contrast, if DOE determines that test 

procedure revisions are not appropriate, 

DOE must publish in the Federal 

Register its determination not to amend 

the test procedures. (42 U.S.C. 

6314(a)(1)(A)(ii)) 

Manufacturers of covered equipment 

must use the Federal test procedures as 

the basis for the following: (1) Certifying 

to DOE that their equipment complies 

with the applicable energy conservation 

standards adopted pursuant to EPCA (42 

U.S.C. 6316(b); 42 U.S.C. 6296), and (2) 

when making representations to the 

public regarding the energy use or 

efficiency of such equipment. (42 U.S.C. 

6314(d)) Similarly, DOE uses these test 

procedures to determine whether the 

equipment complies with relevant 

standards promulgated under EPCA. It 

is noted that DOE does not prescribe a 

test procedure for UFHWSTs, as the 

current Federal standard is an 

insulation design requirement of a 

minimum R-value of R–12.5. 10 CFR 

431.110. 

EPCA contains mandatory energy 

conservation standards for commercial 

heating, air-conditioning, and waterheating equipment. (42 U.S.C. 6313(a)) 

Specifically, the statute sets standards 

for small, large, and very large 

commercial package air conditioning 

and heating equipment, packaged 

terminal air conditioners and packaged 

terminal heat pumps, warm-air 

furnaces, packaged boilers, storage 

water heaters, instantaneous water 

heaters, and UFHWSTs. Id. In doing so, 

EPCA established Federal energy 

conservation standards that generally 

corresponded to the levels in the 

ASHRAE Standard 90.1 in effect on 

October 24, 1992 (i.e., ASHRAE 

Standard 90.1–1989). 

If ASHRAE Standard 90.1 is amended 

with respect to the standard levels or 

design requirements applicable under 

that standard for certain commercial 

equipment, including UFHWSTs, not 

later than 180 days after the amendment 

of the standard, DOE must publish in 

the Federal Register for public comment 

an analysis of the energy savings 

potential of amended energy efficiency 

standards. (42 U.S.C. 6313(a)(6)(A)(i)) 

DOE must adopt amended energy 

conservation standards at the new 

efficiency level in ASHRAE Standard 

90.1, unless clear and convincing 

evidence supports a determination that 

adoption of a more-stringent efficiency 

level as a national standard would 

produce significant additional energy 

savings and be technologically feasible 

and economically justified. (42 U.S.C. 

6313(a)(6)(A)(ii)) 

To determine whether a standard is 

economically justified, EPCA requires 

that DOE determine whether the 

benefits of the standard exceed its 

burdens by considering, to the greatest 

extent practicable, the following seven 

factors: 

(1) The economic impact of the standard 

on manufacturers and consumers of the 

products subject to the standard; 

(2) The savings in operating costs 

throughout the estimated average life of the 

product in the type (or class) compared to 

any increase in the price, initial charges, or 

maintenance expenses of the products likely 

to result from the standard; 

(3) The total projected amount of energy 

savings likely to result directly from the 

standard; 

(4) Any lessening of the utility or the 

performance of the products likely to result 

from the standard; 

(5) The impact of any lessening of 

competition, as determined in writing by the 

Attorney General, that is likely to result from 

the standard; 

(6) The need for national energy 

conservation; and 

(7) Other factors the Secretary considers 

relevant. 

(42 U.S.C. 6313(a)(6)(B)(ii) and (C)(i); 42 

U.S.C. 6316(a); 42 U.S.C. 

6295(o)(2)(B)(i)) 

If DOE adopts as a national standard 

the efficiency levels specified in the 

amended ASHRAE Standard 90.1, DOE 

must establish such a standard not later 

than 18 months after publication of the 

amended industry standard. (42 U.S.C. 

6313(a)(6)(A)(ii)(I)) If DOE determines 

that a more-stringent standard is 

appropriate under the statutory criteria, 

DOE must establish the more-stringent 

standard not later than 30 months after 

publication of the revised ASHRAE 

Standard 90.1. (42 U.S.C. 

6313(a)(6)(B)(i)) 

EPCA also requires that every six 

years DOE shall evaluate the energy 

conservation standards for each class of 

certain covered commercial equipment, 

including UFHWSTs, and publish either 

a notice of determination that the 

standards do not need to be amended, 

or a notice of proposed rulemaking 

(NOPR) that includes new proposed 

energy conservation standards 

(proceeding to a final rule, as 

appropriate). (42 U.S.C. 6313(a)(6)(C)(i)) 

EPCA further provides that, not later 

than three years after the issuance of a 

final determination not to amend 

standards, DOE must publish either a 

notice of determination that standards 

for the product do not need to be 

amended, or a NOPR including new 

proposed energy conservation standards 

(proceeding to a final rule, as 

appropriate). (42 U.S.C. 

6313(a)(6)(C)(iii)(II)) DOE must make the 

analysis on which the determination is 

based publicly available and provide an 

opportunity for written comment. (42 

U.S.C. 6313(a)(6)(C)(ii)) Further, a 

determination that more- stringent 

standards would: (1) Result in 

significant additional conservation of 

energy and (2) be both technologically 

feasible and economically justified must 

be supported by clear and convincing 

evidence. (42 U.S.C. 6313(a)(6)(C)(i); 42 

U.S.C. 6313(a)(6)(A)) DOE is publishing 

this NOPD in satisfaction of the 6-year 

review requirement in EPCA, having 

initially determined that DOE lacks 

clear and convincing evidence that 

amended standards for UFHWSTs 

would result in significant additional 

conservation of energy and be 

economically justified. 

B. Background 

1. Current Standards 

The initial Federal standards for 

UFHWSTs, established by EPCA, 

corresponded to the efficiency levels 


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3The parenthetical reference provides a reference 

for information located in the docket. (Docket No. 

EERE–2017–BT–STD–0021, which is maintained at 

https://www.regulations.gov/docket?D=EERE-2017- 

BT- STD–0021). The references are arranged as 

follows: (commenter name, comment docket ID 

number, page of that document). 

contained in ASHRAE Standard 90.1– 

1989. On January 12, 2001, DOE 

amended the standards for UFHWSTs to 

be equivalent to the efficiency level in 

ASHRAE Standard 90.1 as revised in 

October 1999. 66 FR 3336 (January 2001 

final rule). The January 2001 final rule 

established an insulation design 

requirement of a minimum R-value of 

R–12.5 for all UFHWSTs. 66 FR 3336, 

3356 (Jan. 12, 2001). This remains the 

current Federal standard (and the 

standard level specified in the most 

recent version of ASHRAE Standard 

90.1). The current standard is located at 

10 CFR 431.110. 

2. History of Standards Rulemakings for 

UFHWSTs 

As noted previously, the standards for 

UFHWSTs were most recently amended 

in the January 2001 final rule. EPCA 

requires DOE to evaluate the applicable 

energy conservation standard for 

UFHWSTs every 6 years to determine 

whether it needs to be amended. (42 

U.S.C. 6313(a)(6)(C)(i)) Thus, DOE 

published a request for information 

(RFI) on August 9, 2019, which 

identified various issues and sought to 

collect data and information to inform 

its determination, consistent with its 

obligations under EPCA, as to whether 

the UFHWST standards need to be 

amended (the August 2019 RFI). 84 FR 

39220. 

DOE received five comments in 

response to the August 2019 RFI from 

the interested parties listed in Table II.1. 

Discussion of the relevant comments 

provided by these organizations and 

DOE’s responses are provided in the 

appropriate sections of this document. 

TABLE II.1—INTERESTED PARTIES PROVIDING WRITTEN COMMENTS ON THE AUGUST 2019 RFI 

Name Abbreviation Commenter type 

Appliance Standards Awareness Project and Natural Resources Defense Council.ASAP and NRDC .......................... Efficiency Organizations. 

Air-Conditioning, Heating, & Refrigeration Institute ................................ AHRI .............................................. Trade Association. 

Pacific Gas and Electric Company (PG&E), Sand Diego Gas and 

Electric (SDG&E), Southern California Edison (SCE).

CA IOUs ........................................ Investor-Owned Utilities. 

A.O. Smith Corporation ........................................................................... A.O. Smith ..................................... Manufacturer. 

Bradford White Corporation .................................................................... BWC .............................................. Manufacturer. 

A parenthetical reference at the end of 

a comment quotation or paraphrase 

provides the location of the item in the 

public record.3

III. General Discussion 

DOE developed this proposed 

determination after a review of the 

UFHWST market, including product 

literature and product listings in the 

DOE Compliance Certification 

Management System (CCMS) database. 

DOE also considered written comments, 

data, and information from interested 

parties that represent a variety of 

interests. This notice addresses issues 

raised by these commenters. 

A. Product Classes and Scope of 

Coverage 

When evaluating and establishing 

new or amended energy conservation 

standards, DOE typically divides 

covered equipment into equipment 

classes by the type of energy used or by 

capacity or other performance-related 

features that justify differing standards. 

For UFHWSTs, the current standard at 

10 CFR 431.110 is applicable to a single 

equipment class covering all UFHWSTs, 

which is consistent with the standard 

and structure in ASHRAE Standard 

90.1. DOE’s regulations define ‘‘unfired 

hot water storage tank’’ as a tank used 

to store water that is heated externally, 

and that is industrial equipment. 10 

CFR 431.102. The scope of coverage is 

discussed in further detail in section 

IV.A.1 of this NOPD. 

B. Test Procedure 

EPCA sets forth generally applicable 

criteria and procedures for DOE’s 

adoption and amendment of test 

procedures. (42 U.S.C. 6314(a)) As a 

general matter, manufacturers of 

covered ASHRAE equipment must use 

these test procedures to certify to DOE 

that their equipment complies with 

energy conservation standards and to 

quantify the efficiency of their 

equipment. (42 U.S.C. 6316(b); 42 U.S.C. 

6296) DOE’s current energy 

conservation standards for UFHWSTs 

are expressed in terms of a minimum Rvalue for tank insulation. (See 10 CFR 

431.110.) 

DOE does not prescribe a test 

procedure for UFHWSTs; however, 

DOE’s regulations define ‘‘R-value’’ as 

the thermal resistance of insulating 

material as determined using either 

ASTM International (ASTM) C177–13, 

‘‘Standard Test Method for Steady-State 

Heat Flux Measurements and Thermal 

Transmission Properties by Means of 

the Guarded-Hot-Plate Apparatus,’’ or 

ASTM C518–15, ‘‘Standard Test Method 

for Steady-State Thermal Transmission 

Properties by Means of the Heat Flow 

Meter Apparatus’’ and expressed in (°F 

ft2 h/Btu). 10 CFR 431.102. 

In response to the August 2019 RFI, 

DOE received several comments 

encouraging DOE to consider a 

performance-based test procedure for 

UFHWSTs. ASAP and NRDC referenced 

a test procedure notice of proposed 

rulemaking (NOPR) published in the 

Federal Register on May 9, 2016 (81 FR 

28588) (May 2016 CWH TP NOPR) in 

which DOE proposed, among other 

things, a standby loss test for 

UFHWSTs, and a final rule for the test 

procedure for commercial water heating 

(CWH) equipment published in the 

Federal Register on November 10, 2016 

(81 FR 79261), in which DOE suggested 

that it would address comments 

received in response to the May 2016 

CWH TP NOPR in a separate rulemaking 

notice. These commenters encouraged 

DOE to review and finalize the 

performance-based test procedure for 

UFHWSTs before proceeding with a 

UFHWST standards rulemaking, in 

order to not forgo potential additional 

energy savings that could come from 

incorporating standby losses and/or 

other changes to the UFHWST test 

procedure. (ASAP and NRDC, No. 7 at 

pp. 1–2) Similarly, the CA IOUs stated 

that they believe the current R–12.5 

insulation requirement limits consumer 

choice and does not encourage design 

innovation. They likewise encouraged 

DOE to adopt a performance-based 

metric, which they believe would lead 

to additional energy savings. The CA 

IOUs analyzed standby losses for 

commercial storage water heaters in the 

AHRI Directory of Certified Product 

Performance and noted a wide range of 

performance. They stated that this 

suggests the potential for energy savings 


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4 In setting a more-stringent standard for ASHRAE 

equipment, DOE must have ‘‘clear and convincing 

evidence’’ that doing so ‘‘would result in significant 

additional conservation of energy,’’ in addition to 

being technologically feasible and economically 

justified. 42 U.S.C. 6313(a)(6)(A)(ii)(II). This 

language indicates that Congress had intended for 

DOE to ensure that, in addition to the savings from 

the ASHRAE standards, DOE’s standards would 

yield additional energy savings that are significant. 

In DOE’s view, this statutory provision shares the 

requirement with the statutory provision applicable 

to other covered non- ASHRAE equipment that 

‘‘significant conservation of energy’’ must be 

present (42 U.S.C. 6295(o)(3)(B); 42 U.S.C. 6316(a)), 

but it must also be supported with ‘‘clear and 

convincing evidence’’ to permit DOE to set a more 

stringent requirement than ASHRAE. 

opportunities for UFHWSTs, if storage 

water heater tanks are representative of 

UFHWSTs. Commenting more 

specifically, the CA IOUs encouraged 

DOE to consider the thermal losses 

through uninsulated ports. (CA IOUs, 

No. 3 at pp. 1–3) 

In contrast to these comments, BWC 

recommended that DOE maintain the 

requirements for UFHWSTs in terms of 

insulation level, stating that 

performance testing for UFHWSTs 

would be overly burdensome, especially 

considering the relatively small and 

customized nature of the marketplace. 

BWC also expressed concerns that a test 

procedure change, and ultimately an 

energy conservation standards change, 

could have anti-competitive impacts on 

the UFHWST market. (BWC, No. 5 at 

pp. 1–3) AHRI also recommended 

maintaining the current prescriptive 

design requirement (a minimum 

insulation requirement of R–12.5), 

rather than a performance-based metric, 

stating that the prescriptive approach is 

simpler. (AHRI, No. 6 at p. 2) 

As discussed in section II.A of this 

document, DOE is publishing this 

NOPD in satisfaction of the 6-yearlookback review requirement in EPCA, 

which requires DOE to evaluate the 

energy conservation standards for 

certain commercial equipment, 

including UFHWSTs. Under that 

provision, DOE must publish either a 

notice of determination that the 

standards do not need to be amended, 

or a NOPR that includes proposed 

amendments to the energy conservation 

standards (proceeding to a final rule, as 

appropriate) every six years. (42 U.S.C. 

6313(a)(6)(C)(i)) Because test procedure 

amendments to adopt a standby loss 

requirement were not finalized for 

UFHWSTs, for this analysis of potential 

amended standards, DOE has only 

considered potential amended standards 

based on updating the prescriptive 

design requirement for insulation 

R-value. 

C. Technological Feasibility 

1. General 

In evaluating potential amendments 

to energy conservation standards, DOE 

first conducts a market and technology 

assessment to survey all current 

technology options in products on the 

market and prototype designs that could 

improve the efficiency of the products 

or equipment that are the subject of the 

determination. This list of technology 

options for consideration is developed 

in consultation with manufacturers, 

design engineers, and other interested 

parties. DOE then conducts a screening 

analysis for the technologies identified, 

and, as a first step, determines which of 

those means for improving efficiency 

are technologically feasible. DOE 

considers technologies incorporated in 

commercially available equipment or in 

working prototypes to be 

technologically feasible. See generally 

10 CFR 431.4; 10 CFR part 430, subpart 

C, appendix A, section 6(c)(3)(i) and 

7(b)(1). 

After DOE has determined that 

particular technology options are 

technologically feasible, it further 

evaluates each technology option in 

light of the following additional 

screening criteria: (1) Practicability to 

manufacture, install, and service; (2) 

adverse impacts on equipment utility or 

availability; (3) adverse impacts on 

health or safety; and (4) unique-pathway 

proprietary technologies. See generally 

10 CFR 431.4; 10 CFR part 430, subpart 

C, appendix A, sections 6(c)(3)(ii)–(v) 

and 7(b)(2)–(5). Section IV.A.3 of this 

document discusses the results of the 

screening analysis for UFHWSTs, 

particularly the designs DOE 

considered, those it screened out, and 

those that are the basis for the standards 

considered in this proposed 

determination. 

2. Maximum Technologically Feasible 

Levels 

When DOE proposes to adopt an 

amended standard for a type or class of 

covered equipment, as part of its 

analysis, the Department determines the 

maximum improvement in energy 

efficiency or maximum reduction in 

energy use that is technologically 

feasible for such equipment. 

Accordingly, in the engineering 

analysis, DOE determined the maximum 

technologically feasible (max-tech) 

improvements in energy efficiency for 

UFHWSTs, using the design parameters 

for the most efficient equipment 

available on the market or in working 

prototypes. The max-tech levels that 

DOE determined for this analysis are 

described in section IV.B of this 

proposed determination. 

D. Energy Savings 

1. Determination of Savings 

For each efficiency level (EL) 

evaluated, DOE projected energy savings 

from application of the EL to the 

UFHWSTs purchased in the 30-year 

period that begins in the assumed year 

of compliance with the potential 

amended standards (2025–2054). The 

savings are measured over the entire 

lifetime of the UFHWSTs purchased in 

the previous 30-year period. DOE 

quantified the energy savings 

attributable to each EL as the difference 

in energy consumption between each 

standards case and the no-newstandards case. The no-new-standards 

case represents a projection of energy 

consumption that reflects how the 

market for equipment would likely 

evolve in the absence of amended 

energy conservation standards. DOE 

used a simplified National Impacts 

Analysis (NIA) spreadsheet model to 

estimate national energy savings (NES) 

from potential amended or new 

standards for UFHWSTs. The simplified 

NIA for this analysis is to ascertain if 

potential efficiency improvements for 

UFHWSTs meet the required 

significance of savings described in 

section III.D.2 of this document; 

however, it does not estimate the net 

present value (NPV) to the Nation of 

these savings that is typically performed 

as part of the NIA. The simplified NIA 

spreadsheet model (described in section 

IV.F of this document) calculates energy 

savings in terms of site energy, which is 

the energy directly consumed by 

equipment at the locations where it is 

used. 

2. Significance of Savings 

In determining whether amended 

standards are needed for covered 

equipment addressed by ASHRAE 

Standard 90.1, DOE must consider 

whether such standards would result in 

significant additional conservation of 

energy.4 (42 U.S.C. 6313(a)(6)(C)(i); 42 

U.S.C. 6313(a)(6)(A)(ii)(II)) 

EPCA defines ‘‘energy efficiency’’ as 

the ratio of the useful output of services 

from an article of industrial equipment 

to the energy use of such article, 

measured according to the Federal test 

procedures. (42 U.S.C. 6311(3)) EPCA 

defines ‘‘energy use’’ as the quantity of 

energy directly consumed by an article 

of industrial equipment at the point of 

use, as measured by the Federal test 

procedures. (42 U.S.C. 6311(4)) Given 

this context, DOE relies on site energy 

as the appropriate metric for evaluating 

the significance of energy savings. 


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E. Economic Justification 

1. Specific Criteria 

As noted previously, EPCA provides 

seven factors to be considered in 

determining whether a potential energy 

conservation standard is economically 

justified. (42 U.S.C. 6313(a)(6)(B)(ii)(I)– 

(VII)) The following sections provide an 

overview of each of those seven factors. 

a. Economic Impact on Manufacturers 

and Consumers 

In determining the impacts of a 

potential amended standard on 

manufacturers, DOE typically conducts 

a manufacturer impact analysis (MIA). 

In conducting a MIA, DOE uses an 

annual cash-flow approach to compare 

the quantitative impacts between the 

no-new-standards and the amended 

standards cases. The industry-wide 

impacts typically analyzed include: (1) 

Industry net present value (INPV), 

which values the industry on the basis 

of expected future cash flows; (2) cash 

flows by year; (3) changes in revenue 

and income, and (4) other measures of 

impact, as appropriate. However, DOE is 

not proposing amended standards for 

UFHWSTs, and, therefore, this proposed 

determination would have no cash-flow 

impacts on manufacturers. Accordingly, 

as discussed further in section IV.G of 

this document, DOE did not conduct an 

MIA for this NOPD. 

For individual consumers, measures 

of economic impact include the changes 

in the life-cycle cost (LCC) and payback 

period (PBP) associated with new or 

amended standards. These measures are 

discussed further in the following 

section. For consumers in the aggregate, 

DOE also typically calculates the 

national net present value of the 

consumer costs and benefits expected to 

result from particular standards. DOE 

also typically evaluates the impacts of 

potential standards on identifiable 

subgroups of consumers that may be 

affected disproportionately by a 

standard. However, as discussed in 

section V.A.2 of this document, due to 

significant uncertainties regarding the 

costs of alterations to doorways and 

mechanical rooms (which may be 

required in certain replacement 

installations in order to get an UFHWST 

to its installation destination if 

additional insulation thickness makes 

the UFHWST too large for existing 

structures to accommodate) and the lack 

of data indicating the likelihood of such 

alterations being required, any analysis 

conducted by DOE regarding the LCC or 

PBP would be of limited value because 

of the lack of data and high degree of 

uncertainty of the inputs to those 

analyses. Therefore, DOE did not 

estimate the NPV of consumer costs and 

benefits. 

b. Savings in Operating Costs Compared 

to Increase in Price (LCC and PBP) 

EPCA requires DOE to consider the 

savings in operating costs throughout 

the estimated average life of the covered 

product in the type (or class) compared 

to any increase in the price of, or in the 

initial charges for, or maintenance 

expenses of, the covered product that 

are likely to result from a standard. (42 

U.S.C. 6313(a)(6)(B)(ii)(II)) DOE 

typically conducts this comparison in 

its LCC and PBP analysis. 

The LCC is the sum of the purchase 

price of equipment (including its 

installation) and the operating expense 

(including energy, maintenance, and 

repair expenditures) discounted over 

the lifetime of the equipment. The LCC 

analysis requires a variety of inputs, 

such as equipment prices, energy 

consumption, energy prices, 

maintenance and repair costs, 

equipment lifetime, and discount rates 

appropriate for consumers. To account 

for uncertainty and variability in 

specific inputs, such as equipment 

lifetime and discount rate, DOE uses a 

distribution of values, with probabilities 

attached to each value. 

The PBP is the estimated amount of 

time (in years) it takes consumers to 

recover the increased purchase cost 

(including installation) of more-efficient 

equipment through lower operating 

costs. DOE calculates the PBP by 

dividing the change in purchase cost 

due to a more-stringent standard by the 

change in annual operating cost for the 

year that standards are assumed to take 

effect. This type of calculation is known 

as a ‘‘simple’’ payback period because it 

does not take into account changes in 

operating expenses over time or the time 

value of money (i.e., the calculation is 

done at an effective discount rate of zero 

percent). Payback periods greater than 

the life of the equipment indicate that 

the increased total installed cost is not 

recovered by the reduced operating 

expenses. 

For its LCC and PBP analysis, DOE 

assumes that consumers will purchase 

the equipment in the first year of 

compliance with new or amended 

standards. The LCC savings for the 

considered efficiency levels are 

calculated relative to the case that 

reflects projected market trends in the 

absence of new or amended standards. 

As discussed in section IV.D of this 

document, DOE did not conduct an LCC 

and PBP analysis for this NOPD because 

the lack of data and high degree of 

uncertainty of the inputs to those 

analyses meant that the outputs would 

be of little value. 

c. Energy Savings 

Although significant conservation of 

energy is a separate statutory 

requirement for amending an energy 

conservation standard, EPCA requires 

DOE, in determining the economic 

justification of a standard, to consider 

the total projected energy savings that 

are expected to result directly from the 

standard. (42 U.S.C. 

6313(a)(6)(B)(ii)(III)) As discussed in 

section IV.F of this document, DOE uses 

the NIA spreadsheet models to project 

national energy savings. 

d. Lessening of Utility or Performance of 

Equipment 

In establishing equipment classes and 

in evaluating design options and the 

impact of potential standard levels, DOE 

evaluates potential standards that would 

not lessen the utility or performance of 

the considered products. (42 U.S.C. 

6313(a)(6)(B)(ii)(IV)) Because DOE is not 

proposing standards for UFHWSTs, the 

Department has tentatively concluded 

that this proposed determination would 

not reduce the utility or performance of 

UFHWSTs. 

e. Impact of Any Lessening of 

Competition 

EPCA directs DOE to consider the 

impact of any lessening of competition, 

as determined in writing by the 

Attorney General, that is likely to result 

from a proposed standard. (42 U.S.C. 

6313(a)(6)(B)(ii)(V)) Because DOE is not 

proposing standards for UFHWSTs, 

DOE did not transmit a copy of its 

proposed determination to the Attorney 

General for anti-competitive review. 

f. Need for National Energy 

Conservation 

DOE also considers the need for 

national energy conservation in 

determining whether a new or amended 

standard is economically justified. (42 

U.S.C. 6313(a)(6)(B)(ii)(VI)) Because 

DOE has tentatively concluded that it 

lacks clear and convincing evidence that 

amended standards for UFHWSTs 

would result in significant additional 

conservation of energy or be 

economically justified, DOE did not 

conduct a utility impact analysis or 

emissions analysis for this NOPD. 

g. Other Factors 

In determining whether an energy 

conservation standard is economically 

justified, DOE may consider any other 

factors that the Secretary deems to be 

relevant. (42 U.S.C. 

6313(a)(6)(B)(ii)(VII)) To the extent DOE 


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5The terminology ‘‘accessible to the layperson 

and is based on user operation’’ used by CA IOUs 

is quoted from a discussion of product utility 

written by DOE in the context of differentiating 

product classes in a March 12, 2015 notice of 

proposed rulemaking for energy conservation 

standards for residential non- weatherized gas 

furnaces and mobile home furnaces. 80 FR 13120, 

13137. The full document is available at: https://

www.regulations.gov/document?D=EERE-2014-BTSTD-0031-0032 (Last accessed: July 22, 2020). 

identifies any relevant information 

regarding economic justification that 

does not fit into the other categories 

described previously, DOE could 

consider such information under ‘‘other 

factors.’’ 

IV. Methodology and Discussion of 

Related Comments 

This section addresses DOE’s 

consideration of the statutory factors 

and the analyses that DOE has 

performed for this proposed 

determination with regard to UFHWSTs. 

Separate subsections address each 

component of the factors for DOE’s 

consideration, as well as corresponding 

analyses to the extent conducted. DOE 

used a spreadsheet tool to estimate the 

impact of potential energy conservation 

standards. This spreadsheet uses inputs 

from the energy use analysis and 

shipments projections and calculates a 

simplified NES expected to result from 

potential energy conservation standards. 

A. Market and Technology Assessment 

DOE develops information in the 

market and technology assessment that 

provides an overall picture of the 

market for the equipment concerned, 

including the purpose of the equipment, 

the industry structure, manufacturers, 

market characteristics, and technologies 

used in the equipment. This activity 

includes both quantitative and 

qualitative assessments, based primarily 

on publicly-available information. DOE 

also conducted structured, detailed 

interviews with representative 

manufacturers. During these interviews, 

DOE discussed engineering, 

manufacturing, procurement, and 

financial topics to validate assumptions 

used in its analyses, and to identify key 

issues or concerns. These interviews 

were conducted under non-disclosure 

agreements (NDAs), so DOE does not 

document these discussions in the same 

way that it does public comments in the 

comment summaries and DOE’s 

responses throughout the rest of this 

document. 

The subjects addressed in the market 

and technology assessment for this 

proposed determination include: (1) A 

determination of the scope and 

equipment classes; (2) manufacturers 

and industry structure; (3) shipments 

information, (4) market and industry 

trends, and (5) technologies or design 

options that could improve the energy 

efficiency of UFHWSTs. The key 

findings of DOE’s market assessment are 

summarized in the following 

subsections. 

1. Scope of Coverage and Equipment 

Classes 

In this analysis, DOE relied on the 

definition of UFHWSTs in 10 CFR 

431.102, which defines an UFHWST as 

a tank used to store water that is heated 

externally, and that is industrial 

equipment. Any equipment meeting the 

definition of an UFHWST is included in 

DOE’s scope of coverage. UFHWSTs are 

not currently divided into equipment 

classes (i.e., there is a single equipment 

class covering all UFHWSTs). 

In the August 2019 RFI, DOE 

requested comment on whether the 

current definition of UFHWSTs requires 

any revisions, and whether any subcategory divisions should be added. 84 

FR 39220, 39224 (August 9, 2019). In 

response, BWC generally supported the 

definition of UFHWSTs as presented in 

the August 2019 RFI (i.e., the current 

regulatory definition). Similarly, BWC 

also stated that it does not believe any 

subcategory definitions should be 

created and that there is not an 

appropriate way to divide UFHWSTs 

into separate equipment classes. (BWC, 

No. 5 at pp. 1–2) The CA IOUs 

encouraged DOE to ensure that any 

revised definitions of UFHWSTs 

maintain the current scope of coverage, 

and suggested that DOE should not 

consider establishing new equipment 

classes that are not currently available 

in the market. The CA IOUs also 

recommended that equipment class 

differentiations should be based on 

performance- related features that are 

‘‘accessible to the layperson and is 

based on user operation.’’ 5 (CA IOUs, 

No. 3 at pp. 1–3) 

In this proposed determination, 

absent any indication that the scope of 

UFHWSTs as currently defined would 

benefit from amendment, DOE is not 

proposing any changes to the definition 

of UFHWSTs. Similarly, because DOE 

does not have an indication that 

capacity or other performance 

characteristic justifies a different 

standard level, and because commenters 

did not provide any such indication, 

DOE is not proposing to divide 

UFHWSTs into separate equipment 

classes in this NOPD. Therefore, the 

analysis for this NOPD was conducted 

for the existing single equipment class 

covering all UFHWSTs. 

2. Technology Options 

In the August 2019 RFI, DOE 

identified several technology options 

that would be expected to improve the 

efficiency of UFHWSTs. 84 FR 39220, 

39225 (August 9, 2019). These 

technology options were based on 

manufacturer equipment literature and 

publicly- available technical literature. 

Specifically, the technologies identified 

in the August 2019 RFI included the 

following: 

• Improved insulation R-value 

Æ Increased insulation thickness 

Æ Foam insulation 

Æ Advanced insulation types 

D Aerogel 

D Vacuum panels 

D Inert gas-filled panels 

• Pipe and fitting insulation 

• Greater coverage of tank surface area 

with foam insulation (e.g., tank 

bottom) 

3. Screening Analysis 

DOE uses the following five screening 

criteria to determine which technology 

options are suitable for further 

consideration in an energy conservation 

standards rulemaking: 

(1) Technological feasibility. 

Technologies that are not incorporated 

in commercial equipment or in working 

prototypes will not be considered 

further. 

(2) Practicability to manufacture, 

install, and service. If it is determined 

that mass production and reliable 

installation and servicing of a 

technology in commercial equipment 

could not be achieved on the scale 

necessary to serve the relevant market at 

the time of the projected compliance 

date of the standard, then that 

technology will not be considered 

further. 

(3) Impacts on equipment utility or 

equipment availability. If it is 

determined that a technology would 

have significant adverse impact on the 

utility of the equipment to significant 

subgroups of consumers or would result 

in the unavailability of any covered 

equipment type with performance 

characteristics (including reliability), 

features, sizes, capacities, and volumes 

that are substantially the same as 

equipment generally available in the 

United States at the time, it will not be 

considered further. 

(4) Adverse impacts on health or 

safety. If it is determined that a 

technology would have significant 

adverse impacts on health or safety, it 

will not be considered further. 

(5) Unique-Pathway Proprietary 

Technologies. If a design option utilizes 


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6While the UFHWSTs standard addresses heat 

loss through establishing a minimum level of 

insulation, for the purpose of this analysis, the 

levels of improvement are referred to generally as 

‘‘efficiency levels.’’ 

proprietary technology that represents a 

unique pathway to achieving a given 

efficiency level, that technology will not 

be considered further. 

10 CFR part 430, subpart C, appendix 

A, sections 6(c)(3) and 7(b). In summary, 

if DOE determines that a technology, or 

a combination of technologies, fails to 

meet one or more of the listed five 

criteria, it will be excluded from further 

consideration in the engineering 

analysis. 

a. Screened-Out Technologies 

In response to the August 2019 RFI, 

DOE received several comments related 

to the suggested technology options. 

A.O. Smith stated that the technologies 

used to increase the efficiency of 

UFHWSTs are limited to changes in 

installation thickness, location, and 

materials. (A.O. Smith, No. 8 at p. 2) 

BWC stated that many of the 

technologies listed would be very 

difficult to apply to UFHWSTs due to 

the wide variety of tank sizes, 

configurations, and fittings. 

Additionally, BWC stated that the 

majority of the technologies identified 

would present significant 

manufacturability issues due to the 

variability of tank configurations and 

fittings, and that increasing insulation 

thickness and/or changing to another 

insulating solutions could present 

issues with fittings that would not occur 

otherwise. BWC also asserted that the 

technology options listed could increase 

the fragility of tanks, which could cause 

difficulties in moving the tanks to their 

final installation location. (BWC, No. 5 

at p. 2) As discussed in section IV.A of 

this document, DOE also conducted 

interviews with manufacturers. During 

these interviews, which were conducted 

under NDAs, manufacturers made 

statements similar to those comments 

submitted by BWC in response to the 

August 2019 RFI. 

In response to these comments, DOE 

acknowledges that requiring use of 

advanced insulation types (such as 

vacuum panels or aerogels) could 

necessitate an extremely difficult 

change to the UFHWST manufacturing 

process due to the rigid nature of these 

materials and the high degree of 

customization and ports on UFHWSTs. 

Applying these materials closely around 

ports and configuring them to all tank 

shapes and setups (e.g., number of ports, 

port locations) may not be possible 

where tight curvatures would be 

required and/or due to the high level of 

customization of UFHWSTs. 

Additionally, DOE is not aware of 

equipment on the market that 

incorporate aerogels, vacuum panels, or 

inert gas-filled panels at the time of this 

analysis. Therefore, in the analysis for 

this NOPD, DOE did not consider any 

advanced insulation types as a 

technology option to increase the 

insulation R-value for UFHWSTs. 

To explain what technologies are 

commonly used, BWC stated that most 

manufacturers use polyurethane foam to 

achieve the minimum R–12.5 

requirement, although high density 

fiberglass may be applied in certain 

areas where it is difficult to apply foam. 

(BWC, No. 5 at p. 2) Relatedly, A.O. 

Smith stated that certain technology 

options proposed by DOE, such as 

insulation on tank bottoms, would be 

impractical to implement because 

bottom mounted drain connections 

must be kept accessible. (A.O. Smith, 

No. 8 at p. 2) AHRI commented that 

technologies such as pipe insulation 

cannot be pre-configured by the 

manufacturer for installation in the 

field. (AHRI, No. 6 at p. 2) 

As suggested by BWC, and supported 

by DOE’s review of publicly-available 

manufacturer information, polyurethane 

foam is the most commonly used type 

of insulation for meeting the minimum 

insulation requirement, but fiberglass 

and/or Styrofoam are often used in 

specific regions (e.g. tank tops or 

bottoms, or regions around ports) where 

doing so could limit access to ports or 

be impractical to manufacture. For its 

analyses, DOE has estimated energy 

losses based on tanks being covered 

primarily with polyurethane foam, but 

the agency has also included several 

regions with alternative insulation 

materials. Therefore, DOE included a 

minimum amount of insulation around 

pipes and fittings in its analysis of 

baseline equipment, but it did not 

consider requiring different insulation 

materials in these regions. Likewise, 

DOE did not consider additional 

insulation coverage around pipes and 

fittings as a technology option for the 

analysis. 

b. Remaining Technologies 

Ultimately, after reviewing all of the 

proposed technologies, DOE did not 

screen out improved insulation R-value 

due to increased polyurethane foam 

thickness, so the Department included 

this as a design option in the 

engineering analysis. DOE determined 

that this technology option is 

technologically feasible because it only 

involves an increase in thickness of the 

same insulation material that is 

currently commonly used on 

UFHWSTs, and can be achieved with 

the same processes that are currently 

being used in commercially-available 

equipment or working prototypes (e.g., 

fabricating jackets or foaming). 

B. Engineering Analysis 

The purpose of the engineering 

analysis is to establish the relationship 

between the efficiency and cost of 

UFHWSTs at different levels of reduced 

heat loss (‘‘efficiency levels’’).6 This 

relationship serves as the basis for the 

cost-benefit calculations for commercial 

consumers, manufacturers, and the 

Nation. There are typically two 

elements to consider in the engineering 

analysis; the selection of efficiency 

levels to analyze (i.e., the ‘‘efficiency 

analysis’’) and the determination of 

equipment cost at each efficiency level 

(i.e., the ‘‘cost analysis’’). In determining 

the performance of higher-efficiency 

equipment, DOE considers technologies 

and design option combinations not 

eliminated by the screening analysis. 

DOE then typically estimates the 

manufacturing production cost (MPC) at 

the baseline and the change in MPC 

associated with reducing the heat loss of 

equipment above the baseline, up to the 

max-tech efficiency level for each 

equipment class. The typical output of 

the engineering analysis is a set of costefficiency ‘‘curves’’ that are used in 

downstream analyses (i.e., the LCC and 

PBP analyses and the NIA). However, 

for the reasons discussed in IV.B.3 of 

this document, the cost analysis was not 

performed for this NOPD. 

1. Efficiency Levels for Analysis 

DOE typically uses one of two 

approaches to develop energy efficiency 

levels for the engineering analysis: (1) 

Relying on observed efficiency levels in 

the market (i.e., the efficiency-level 

approach), or (2) determining the 

incremental efficiency improvements 

associated with incorporating specific 

design options to a baseline model (i.e., 

the design-option approach). Using the 

efficiency-level approach, the efficiency 

levels established for the analysis are 

determined based on the market 

distribution of existing equipment (in 

other words, based on the range of 

efficiencies and efficiency level 

‘‘clusters’’ that already exist on the 

market, without regard to the specific 

design options used to achieve those 

levels). Using the design-option 

approach, the efficiency levels 

established for the analysis are 

determined through detailed 

engineering calculations and/or 

computer simulations of the efficiency 

improvements resulting from 

implementation of specific design 


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options that have been identified in the 

technology assessment. DOE may also 

rely on a combination of these two 

approaches. In this rulemaking, DOE is 

adopting a design-option approach 

because there are very few models of 

UFHWSTs currently on the market that 

are marketed with higher insulation 

levels than the current baseline 

requirement of R–12.5. 

Based on its review of publiclyavailable equipment information and 

feedback from manufacturers, DOE had 

tentatively determined that 2 inches of 

polyurethane foam insulation is needed 

to meet the current insulation 

requirement, and DOE, therefore, 

considered this insulation thickness as 

the baseline. As discussed in section 

IV.A.3 of this document, increased 

polyurethane foam insulation thickness 

was the only technology option that was 

not screened-out for this analysis, and 

thus, DOE considered more-stringent 

efficiency levels (i.e., increased R-value) 

based on varying levels of increased 

polyurethane foam thickness. 

In response to the August 2019 RFI, 

AHRI commented that there is a 

diminishing return from increasing 

insulation thickness due to the 

increasing heat transfer rate and surface 

area as the insulation thickness 

increases. (AHRI, No. 6 at pp. 1–2) This 

comment was supported by individual 

manufacturers during interviews with 

DOE. Manufacturers stated that surface 

tension decreases as the foam thickness 

increases, which results in the foam 

becoming less stable. To counter this, 

less blowing agent is used and the foam 

becomes denser, thereby reducing the 

added insulating benefit per inch of 

applied insulation at thicknesses above 

3 inches (if foam is applied by being 

poured into a form, which is the typical 

application method for polyurethane 

foam on jacketed UFHWSTs). 

Manufacturers stated that due to the 

changing foam density as the insulation 

thickness increases, the R-value per 

inch is expected to diminish as 

insulation thickness is increased, 

especially as thickness increases beyond 

3 inches. As a result, when more than 

3 inches of insulation thickness is 

applied, it is unclear how much 

additional R-value could be achieved by 

continuing to increase the thickness of 

the foam of jacketed UFHWSTs. 

Unjacketed tanks, which are intended 

for outdoor installation and may not 

have the same space constraints as 

indoor units, do not have an outer metal 

jacket enclosing and protecting the 

foam. As a result, unjacketed tanks can 

be spray-foamed in layers, which 

reduces the compression of the foam 

and mitigates the potential for changes 

in foam density at thicknesses above 3 

inches. However, all UFHWSTs were 

considered in a single equipment class 

(as discussed in section IV.A.1 of this 

document), so the max-tech level for 

jacketed UFHWSTs was applied for all 

UFHWSTs in this analysis. 

Furthermore, feedback from 

manufacturers and DOE’s previous 

knowledge of the UFHWST market 

indicated that at least 90 percent of 

UFHWSTs are jacketed and intended for 

indoor installation. 

Therefore, DOE expects uncertainty 

related to the effective R-value of 

insulation for insulation thicknesses 

above 3 inches. Because thicknesses 

above 3 inches are not typically used on 

jacketed UFHWSTs, the improvement in 

R-value as insulation thickness 

increases beyond 3 inches for jacketed 

tanks is unclear at this time. Therefore, 

due to the high level of uncertainty 

regarding the R-value of foam insulation 

with thickness greater than 3 inches, 

DOE has limited its analysis to 

considering only up to 1 additional inch 

of insulation thickness above the 

baseline insulation level of 2 inches, so 

3 inches of foam insulation was 

considered the max-tech efficiency level 

for UFHWSTs in this analysis. 

DOE requests data and information 

related to achievable R-values of 

polyurethane foam insulation on 

jacketed UFHWSTs at thicknesses above 

3 inches. DOE also seeks comment on 

its understanding of the difficulties 

associated with applying more than 3 

inches of foam to jacketed UFHWSTs. 

DOE also included one intermediate 

level of added insulation in its analysis, 

with 0.5 inch of added insulation above 

the 2-inch baseline that results in R– 

12.5. DOE has assumed for its analysis 

that polyurethane foam has an R-value 

per inch of 6.25 (up to a maximum 

thickness of 3 inches). The selected ELs 

used in the analyses for this NOPD are 

shown in Table IV.1. 

TABLE IV.1—EFFICIENCY LEVELS FOR

REPRESENTATIVE UFHWSTS BASED

ON INCREASED INSULATION

Efficiency 

levels 

Insulation 

thickness 

(polyurethane 

foam) 

R-value of 

insulation 

Baseline— 

EL0.

2 inches ......... R–12.5. 

EL1 ............... 2.5 inches ...... R–15.625. 

EL2 ............... 3 inches ......... R–18.75. 

DOE seeks comment on the 

considered efficiency levels analyzed 

for UFHWSTs. Additionally, DOE seeks 

comment on its assumption that 

polyurethane foam has an R-value per 

inch of 6.25, up to a maximum 

thickness of 3 inches. 

2. Representative Equipment for 

Analysis 

For the engineering analysis, DOE 

analyzed the publicly-available details, 

including storage volumes and other 

critical features, of UFHWST models 

available on the market and conducted 

interviews with manufacturers under 

NDAs to determine appropriate 

representative equipment to analyze. In 

response to the August 2019 RFI, several 

commenters highlighted the customized 

and variable nature of the UFHWST 

market. (BWC, No. 5 at pp. 1–2; AHRI, 

No. 6 at p. 2; A.O. Smith, No. 8 at p. 

1) BWC stated that it does not believe 

it is possible to have one representative 

volume of UFHWSTs (or more in a 

reasonable quantity). BWC also 

commented that it would be difficult to 

have a representative application with 

associated R-value, ambient conditions, 

tank setpoint, and draw patterns for 

UFHWSTs and suggested that DOE’s 

analysis should not be overly simplified 

if it is acknowledged that tank 

orientation can affect heat losses. (BWC, 

No. 5 at pp. 2–3) A.O. Smith 

recommended that DOE conduct its 

analysis using various standard models, 

but the agency should keep in mind the 

customized nature of the UFHWST 

market. (A.O. Smith, No. 8 at p. 1) 

To account for the wide range of 

UFHWSTs on the market, DOE chose 

several representative baseline units for 

analysis. As discussed in section 

IV.C.1.c of this document, DOE also 

included several ambient temperature 

conditions in its energy use analysis to 

reflect typical installation locations (i.e., 

indoors in mechanical rooms or 

outdoors in ‘‘Very Hot’’ and ‘‘Hot’’ 

regions). Although UFHWSTs can be 

installed horizontally or vertically, DOE 

used a conservative assumption in its 

energy use analysis that water 

temperature would remain uniformly at 

140 °F (as discussed in section IV.C.1.b 

of this document, DOE did not consider 

stratification of water temperatures 

inside the tank and assumed that a tank 

would always be full of hot water). 

Therefore, DOE determined that 

installation orientation would not have 

a significant impact on its energy use 

analysis results, so the Department 

calculated estimated standby losses 

based on all tanks being vertical, 

because vertical installations are the 

most common. The characteristics of 

these representative units are listed in 

Table IV.2. 


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TABLE IV.2—REPRESENTATIVE TANK CHARACTERISTICS

Volume range 

(gal.) 

Representative 

volume 

(gal.) 

Representative 

dimensions 

Height 

(in.) 

Diameter 

(in.) 

0 to 100 ........................................................................................................................................ 50 47 22 

101 to 250 .................................................................................................................................... 175 65 28 

251 to 500 .................................................................................................................................... 375 72 42 

501 to 1000 .................................................................................................................................. 750 141 42 

1001 to 2000 ................................................................................................................................ 1500 124 60 

2001 to 5000 ................................................................................................................................ 3500 168 84 

>5000 ........................................................................................................................................... 5000 180 96 

In response to the August 2019 RFI, 

BWC stated that most manufacturers use 

polyurethane foam to insulate 

UFHWSTs, although fiberglass may be 

used in certain areas or on certain tanks 

where it is difficult to apply foam. 

(BWC, No. 5 at p. 2) As discussed in 

section IV.C.1 of this document, in its 

energy use analysis, DOE divided the 

surface area of each tank, at each EL, 

into several zones and assigned a 

representative R-value to each zone 

depending on the expected insulation 

type and thickness. Although most tank 

surfaces can be insulated with 2 inches 

of polyurethane foam, it is not practical 

to insulate all surfaces with 

polyurethane foam due to the insulation 

application process or the need to retain 

access to certain ports. In particular, it 

can be difficult to insulate the areas 

surrounding fittings, manholes or 

handholes, and the tops or bottoms of 

tanks with polyurethane foam, so DOE 

accounted for the use of other insulating 

materials in those areas. Similarly, 

certain fittings and ports will remain 

uninsulated due to the need to be 

accessible, situations for which DOE 

also accounted in its analysis. 

In publicly-available equipment 

literature, DOE observed that the typical 

number of ports on UFHWSTs ranged 

from 5 to 11. These ports can include an 

inlet port, an outlet port, a temperature 

sensor, a temperature and pressure relief 

valve, a drain, a recirculation valve, one 

or more ports for anode rods, and other 

custom fittings. In its energy use 

analysis, DOE selected 7 ports as a 

representative number of ports. DOE 

further assumed that a 2-inch-wide ring 

of fiberglass would be placed around 

each port. DOE also included a small 

area (1.5 inches in diameter) of 

uninsulated tank at each port to reflect 

losses through adjoining pipes or 

fittings. Wherever fiberglass was 

modeled as the insulation for tanks, the 

thickness of fiberglass was the same as 

the thickness of polyurethane foam on 

the same tank (which for the analysis in 

this NOPD, depends on the EL) because 

the thickness of insultation would be 

uniformly constrained by the outer 

metal jacketing on most UFHWSTs. The 

R-values for each insulation type and at 

each EL are shown in Table IV.3. 

TABLE IV.3—INSULATION R-VALUES

Material R-value per 

inch 

Effective R-value 

EL0 EL1 EL2 

Polyurethane Foam ......................................................................................... 6.25 12.5 15.625 18.75 

Fiberglass ........................................................................................................ 3.5 7 8.75 10.5 

Bare Tank (free convective heat transfer to air) ............................................. N/A 0.33 0.33 0.33 

Based on feedback from 

manufacturers and its own review of 

publicly-available materials, DOE also 

assumed that the tank tops would be 

covered with fiberglass instead of 

polyurethane foam, and that an extra 

maintenance access port (a 6 inch by 4 

inch hand hole for tanks with storage 

volumes up to 500 gallons, or a 12 inch 

by 16 inch manhole for tanks with 

storage volumes greater than 500 

gallons) would be partially covered with 

fiberglass and partially bare. 

DOE requests comment on the inputs 

and assumptions used in its engineering 

analysis. In particular, DOE requests 

input on its choice of representative 

volumes, its assumptions about the 

typical coverage of various insulation 

materials, and its estimated R-values for 

each insulation material at each EL 

considered. 

3. Cost Analysis 

The cost analysis portion of the 

Engineering Analysis is typically 

conducted using one or a combination 

of cost approaches. The selection of cost 

approach depends on a suite of factors, 

including the availability and reliability 

of public information, characteristics of 

the regulated equipment, and the 

availability and timeliness of 

purchasing the equipment on the 

market. The cost approaches are 

summarized as follows: 

• Physical teardowns: Under this 

approach, DOE physically dismantles 

commercially-available equipment, 

component-by-component, to develop a 

detailed bill of materials for the 

equipment. 

• Catalog teardowns: In lieu of 

physically deconstructing equipment, 

DOE identifies each component using 

parts diagrams (available from sources 

such as manufacturer websites or 

appliance repair websites) to develop 

the bill of materials for the equipment. 

• Price surveys: If a physical or 

catalog teardown is infeasible (e.g., for 

tightly integrated equipment such as 

fluorescent lamps, which are infeasible 

to disassemble and for which parts 

diagrams are unavailable), costprohibitive, or otherwise impractical 

(e.g. large commercial boilers), DOE 

conducts price surveys using publiclyavailable pricing data published on 

major online retailer websites and/or by 

soliciting prices through distributors or 

other commercial channels. 

As discussed in section IV.D of this 

document, DOE did not conduct a cost 


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7Available at: https://www.regulations.gov/ 

document?D=EERE-2014-BT-STD-0042-0016, 

section 5.5.3 (Last accessed: April 8, 2020). 

8The TMY data sets hold hourly values of solar 

radiation and meteorological elements for a 1-year 

period. Their intended use is for computer 

simulations of solar energy conversion systems and 

building systems to facilitate performance 

comparisons of different system types, 

configurations, and locations in the United States 

and its territories. Because they represent typical 

rather than extreme conditions, they are not suited 

for designing systems to meet the worst-case 

conditions occurring at a location. 

9Wilcox, S. and W. Marion, 2008 User’s Manual 

for TMY3 Data Sets, NREL/TP–581–43156 (April 

2008) (Available at: https://www.nrel.gov/docs/ 

fy08osti/43156.pdf). 

10Building America Best Practices Series, 

Volume 7.3, Guide to determining climate regions 

by county 2015 (Available at: https://

www.energy.gov/sites/prod/files/2015/10/f27/ba_

climate_region_guide_7.3.pdf). 

11U.S. Census Population Estimates by County, as 

of 2018 (Available at: https://www.census.gov/data/ 

tables/time-series/demo/popest/2010s-countiestotal.html#par_textimage). 

analysis because DOE did not have the 

requisite inputs to develop its LCC 

model with a degree of certainty that 

would meet the statute’s ‘‘clear and 

convincing’’ evidentiary threshold. DOE 

likewise did not expend resources to 

generate the cost-efficiency curve, as it 

is unnecessary without an LCC model to 

feed into. 

C. Energy Use Analysis 

As discussed, UFHWSTs store hot 

water and do not directly consume fuel 

or electricity for the purpose of heating 

water, so any potential amendments to 

the standard would reduce standby loss 

of heat from the stored water. Further, 

DOE currently only prescribes a 

minimum insulation requirement (as 

opposed to a minimum efficiency 

requirement) for UFHWSTs. 

Accordingly, the energy use analysis 

determines the annual energy 

consumption of paired water heaters 

and boilers due to standby loss of the 

UFHWSTs and assesses the energy 

savings potential of increasing the 

stringency of the required insulation for 

UFHWSTs. 

1. Tank Thermal Loss Model 

For this determination, DOE adapted 

the thermal loss model described in the 

technical support document (TSD) for 

the commercial water heating energy 

conservation standards (ECS) NOPR 

published in the Federal Register on 

May 31, 2016 (81 FR 34440; May 2016 

CWH ECS NOPR), with some 

modifications to how the tank surface 

areas are defined.7 These modifications 

were introduced to capture equipment 

performance that results from 

differences in surface insulation 

thickness over different areas of tank 

(i.e., insulation around fittings and 

access ports). These differences are 

described in section IV.C.1.a of this 

document. 

Where: 

Qhr, j = The hourly heat loss for the UFHWST 

for each efficiency level (EL) j (Btu/hr). 

i = The surface area of the cylindrical tank 

is divided into different zones each 

indexed i. 

Ai, j = The area of each zone i at each EL j(ft2). 

Ti = The constant internal water temperature 

for each tank zone i (°F). 

Tamb,z = The ambient air temperature for each 

climate zone z (°F). 

Ri, j = The net R-value of the insulation for 

each zone i at each EL j (°Fl·ft2·hr/Btu). 

a. Tank Surface Area (Ai, j) 

As discussed in section IV.B.2 of this 

document, DOE used a conservative 

assumption in its energy use analysis 

that water temperature would remain 

uniformly at 140 °F and did not 

consider stratification of water 

temperatures inside the tank. Therefore, 

although tanks can be installed 

horizontally or vertically, there is no 

difference in thermal losses between 

these configurations, and DOE only 

used vertical tanks in its analysis. The 

UFHWST’s total external surface area 

was divided into separate zones, where 

i is the index for each zone. Zones 

represent the different areas of an 

UFHWST that would have unique 

insulative values. These zones are 

described in more detail in in section 

IV.B of this document. 

ATankTop = When the UFHWST is oriented 

vertically, this represents the tank’s top 

surface. 

AFittings = Is the sum of all uninsulated areas 

of the tank’s surface devoted to fittings. 

AFittingInsulation = Is the sum of all insulated 

areas of the tank’s surfacesurrounding 

the (uninsulated) fittings. 

AAccessPort = Is the sum of all insulated areas 

of the tank’s surface devoted to the tank’s 

cleanout hand hole port or manhole. 

ATankWall = When the UFHWST is oriented 

vertically, this represents the tank’s 

walls. 

ATankBottom = When the UFHWST is oriented 

vertically, this represents the tank’s 

bottom surface. 

b. Tank Internal Water Temperature (Ti) 

For this analysis, DOE assumed that 

the water inside the UFHWSTs is at a 

constant uniform temperature of 140 °F, 

which is the average water temperature 

required by the current Federal test 

procedures for storage-type CWH 

equipment during standby loss testing. 

See generally 10 CFR 431.106; 10 CFR 

part 431, subpart G, appendix A, section 

6; 10 CFR part 431, subpart G, Appendix 

B, section 5. Because UFHWSTs serve 

the same function as storage-type CWH 

equipment in standby mode, DOE 

expects that similar conditions would 

be appropriate for UFHWSTs as for 

storage-type CWH equipment in standby 

mode. DOE used a conservative 

assumption that internal water 

temperatures would remain indefinitely 

at 140 °F. In reality, the rate of heat loss 

from a UFHWST would decrease slowly 

as the temperature difference between 

the internal stored water and the 

ambient air decreased. However, 

because this effect would be minimal, 

DOE did not consider stratification of 

water temperatures inside the tank and 

assumed that a tank would always be 

full of hot water. Therefore, DOE held 

the temperature T constant across all 

tank zones i. 

DOE requests comment on the 

appropriateness of its assumption 

regarding the use of a constant internal 

water temperature of 140 °F. 

c. Tank Ambient Temperature (Tamb, z) 

Based on feedback from 

manufacturers during interviews 

conducted under NDA, DOE assumed 

that 90 percent of UFHWSTs would be 

installed indoors and that the remaining 

10 percent would be installed outdoors. 

DOE assumed that all tanks that are 

installed indoors would have a constant 

ambient temperature of 75 °F, which is 

the average air temperature required by 

the current Federal test procedure for 

storage-type CWH equipment during 

standby loss testing. See generally 10 

CFR 431.106; 10 CFR part 431, subpart 

G, appendix A, section 6; 10 CFR part 

431, subpart G, Appendix B, section 5. 

For the fraction of UFHWSTs that are 

installed in outdoor, or nonconditioned, spaces, DOE defined each 

climate zone (z) and calculated the 

monthly average temperatures from 

Typical Meteorological Year 3 (TMY3) 8

data for the Building America climate 

regions 1A, 2A, and 2B.9 10 The 

temperatures for each region are 

represented by the cities in Table IV.4. 

The monthly regional averages were 

then weighted using the regional city 

populations based on data from 2018 

Census.11


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TABLE IV.4—CLIMATE ZONES AND REPRESENTATIVE CITIES

Climate zone Population Representative city TMY 

location No. 

1A ......................................................................................................................................... 6,208,359 Miami .................... 722020 

2A ......................................................................................................................................... 38,418,718 Houston ................. 722430 

2B ......................................................................................................................................... 6,869,283 Phoenix ................. 722780 

3A ......................................................................................................................................... 43,230,951 Atlanta ................... 722190 

3B—CA ................................................................................................................................. 29,951,605 Los Angeles .......... 722950 

3B—Non CA ......................................................................................................................... 5,546,151 Las Vegas ............. 723677 

3C ......................................................................................................................................... 8,596,694 San Francisco ....... 724940 

4A ......................................................................................................................................... 69,154,015 Baltimore ............... 724060 

4B ......................................................................................................................................... 2,245,023 Albuquerque .......... 723650 

4C ......................................................................................................................................... 9,696,610 Seattle ................... 727930 

5A ......................................................................................................................................... 70,727,419 Chicago ................. 725300 

5B ......................................................................................................................................... 13,119,013 Boulder .................. 724699 

6A ......................................................................................................................................... 17,705,715 Minneapolis ........... 726580 

6B ......................................................................................................................................... 2,650,907 Helena ................... 727720 

7 ............................................................................................................................................ 2,625,239 Duluth .................... 727450 

8 ............................................................................................................................................ 170,286 Fairbanks .............. 702610 

While a UFHWST can be installed 

outdoors anywhere in the Nation, for 

this analysis, DOE is using the 

assumption that these installations will 

only occur in the ‘‘Very Hot’’ and ‘‘Hot’’ 

regions (Building America climate zones 

1A, 2A, and 2B) where the chance of 

overnight freezing is very low. 

Table IV.5 shows the fraction of 

UFHWSTs installed indoors versus 

outdoors, and the monthly average 

ambient temperature values for each 

Tamb, z. 

TABLE IV.5—AVERAGE MONTHLY AMBIENT TEMPERATURES

Climate zone/location 

(z) 

Location 

weight 

Average temperature for month 

(°F) 

1 2 3 4 5 6 7 8 9 10 11 12 

1A .............................................................................................. 0.012 67 70 71 75 80 82 83 82 81 79 74 69 

2B .............................................................................................. 0.075 55 60 63 75 81 93 96 93 87 77 64 53 

2A .............................................................................................. 0.013 51 55 61 69 75 81 83 83 80 69 63 55 

Indoor ........................................................................................ 0.900 75 75 75 75 75 75 75 75 75 75 75 75 

DOE requests comment on its 

assumption regarding the typical 

ambient temperatures for UFHWSTs 

installed indoors and outdoors. 

DOE requests comment on its 

assumption that 10 percent of all 

UFHWST would be installed outdoors. 

DOE requests information on the typical 

capacities and R-values of outdoor 

equipment. 

DOE requests comment on its 

assumption that outdoor installations 

would be limited to climate zones 1A, 

2A, and 2B. DOE requests information 

or data on the fraction of installations 

that occur within these, or other, 

climate zones. 

d. R-value of Insulation (Ri, j) 

The R-value of each zone i of the 

UFHWST is defined for each EL j in the 

engineering analysis in Table IV.1 and 

Table IV.3 of section IV.B of this 

document. 

DOE requests comment on its Tank 

Thermal Loss Model. 

2. Annual Energy Use Due to UFHWST 

Losses 

To calculate the energy used by the 

boiler attributable to the heat losses of 

the UFHWSTs, DOE used the following 

equation for each EL listed in Table IV.1 

of this document: 

Where: 

EBoilj = The energy by the boiler required to 

maintain the water temperature in the 

UFHWST at the temperature Ti at each 

EL j, (Btu/yr), 

Qhr, j = hourly heat loss for the UFHWST at 

each EL j (see section IV.C.1, (Btu/hr) of 

this document), and 

Boilern = average boiler efficiency (%) in year 

yr (defined in section IV.F.2 of this 

document). 

Table IV.6 presents the energy used 

by the boiler attributable to the heat 

losses of the UFHWST at the baseline 

(EL 0) and each EL by tank capacity. 

Table IV.7 presents the resulting energy 

savings at each EL above baseline. The 

representative storage volumes used in 

this analysis are discussed in section 

IV.B.2 of this document. 


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1 

l Q . X 8760 X ·z EBoi j = hr,1 Boi er11 ,yr 
30808 Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 

12The projected value for Boiler Efficiency 

(Boilern) is 0.922 in 2027, see section IV.F.2 of this 

document for more details. 

TABLE IV.6—BOILER ENERGY USE DUE TO UFHWST HEAT LOSSES IN 2025 (MMBTU/YR) 12

EL 

Capacity (US gal) 

50 175 375 750 1500 3500 5000 

0 ........................................................................................... 1.76 2.78 4.71 8.59 11.44 21.09 25.27 

1 ........................................................................................... 1.55 2.39 3.97 7.32 9.63 17.45 20.80 

2 ........................................................................................... 1.41 2.13 3.48 6.48 8.42 15.02 17.83 

TABLE IV.7—SAVINGS IN BOILER ENERGY USE DUE TO REDUCED UFHWST HEAT LOSSES IN 2025 (MMBTU/YR) 

EL 

Capacity (US gal) 

50 175 375 750 1500 3500 5000 

1 ........................................................................................... 0.21 0.39 0.74 1.26 1.81 3.64 4.47 

2 ........................................................................................... 0.35 0.64 1.23 2.10 3.02 6.07 7.44 

3. Additional Sources of Uncertainty 

As discussed in section IV.B.2 of this 

document, the inputs to DOE’s tank 

thermal loss model were primarily 

based on publicly-available information, 

DOE’s previous knowledge of 

UFHWSTs, and feedback from 

manufacturers received during 

interviews conducted under NDAs. To 

validate the model, DOE compared the 

results produced by the model to results 

of testing previously conducted to 

evaluate the performance-based test 

procedure proposed for UFHWSTs in 

the May 2016 CWH TP NOPR, which 

was largely based on the standby loss 

test procedure for commercial storage 

water heaters. The proposed test 

procedure included a standby loss test 

that would be conducted as the mean 

tank water temperatures decay from 

142 °F to 138 °F at a nominal ambient 

temperature of 75 °F. 81 FR 28588, 

28603 (May 9, 2016). Standby loss tests 

were conducted on 17 UFHWSTs with 

an advertised insulation level of R–12.5 

and storage volumes of 40, 80, or 120 

gallons in order to gather data on 

whether measured standby losses were 

consistent with what would be expected 

from tanks insulated to their rated and/ 

or advertised insulation levels, to assess 

the repeatability and sensitivity of the 

proposed test procedure, and to gather 

data on the potential burden in 

conducting the testing. 

DOE used the same analytical model 

described in this section to calculate the 

expected losses from each of these 

tanks, using their measured dimensions 

and actual number of ports. As 

discussed, the internal water 

temperature (140 °F) and ambient air 

temperature (75 °F) used for the 

analytical model were the same as the 

average temperatures seen during the 

physical testing. The same assumptions 

about insulation details (e.g., R-values 

for different materials and the use of 

fiberglass around ports) were used as 

were used for the baseline (R–12.5) 

units in DOE’s thermal loss model. The 

average predicted rate of standby losses 

for these tanks were 73 percent of the 

measured standby losses and ranged 

from as low as 58 percent of the 

measured losses up to 90 percent of the 

measured losses. Because the estimated 

standby losses are significantly lower 

than the measured losses, this suggests 

that DOE’s thermal loss model 

undercounts the actual standby losses 

that would occur in the field. 

Furthermore, the wide range in 

calculated standby losses as compared 

to measured standby losses indicates 

that the accuracy of the thermal loss 

calculations in predicting the standby 

losses of a particular model will be 

somewhat unpredictable, thereby 

adding additional uncertainty. 

Furthermore, when DOE conducted 

standby loss tests of UFHWSTs, it found 

that tanks with identical storage 

volumes, dimensions, number of ports, 

and nominal insulation levels differed 

by up to 8.5 percent, whereas DOE’s 

model would predict the same level of 

standby losses for these tanks. This 

finding suggests that there may be 

variations in the extent of R–12.5 

coverage between units, even between 

units from the same manufacturer. As 

discussed in section IV.B.2 of this 

document, it may not be practical to 

insulate all surfaces of UFHWSTs with 

polyurethane foam due to the nature of 

the insulation application process or the 

need to retain access to certain ports. 

Differences in manufacturers’ tank 

designs, manufacturing processes, or 

their interpretations of the R–12.5 

insulation requirement could lead to 

variations in the amount of tank surface 

area that is actually insulated with R– 

12.5. Therefore, tanks that appear to 

have the same attributes and insulation 

may have different levels of standby 

losses in the field. This source of 

potential variation in standby losses 

further supports DOE’s conclusion that 

there may be additional sources of 

thermal losses that vary between tanks 

and that are not adequately captured in 

its current thermal loss model. This 

variation also makes it very difficult for 

DOE to characterize the representative 

performance of a ‘‘baseline’’ UFHWST, 

or the expected performance at any 

potential amended standard level, with 

a high degree of confidence since there 

is significant variation in thermal energy 

losses at a given efficiency level (Rvalue) that cannot be readily predicted 

or otherwise accounted for in the 

analysis. Due to these potential 

variations in insulation coverage and 

because DOE has not been able to verify 

its thermal loss model against its 

physical test results, there is significant 

uncertainty as to the validity of its 

energy use analysis. 

D. Life-Cycle Cost and Payback Period 

Analysis 

To determine whether a standard is 

economically justified, EPCA requires 

DOE to consider the economic impact of 

the standard on manufacturers and 

consumers, as well as the savings in 

operating costs throughout the 

estimated average life of the equipment 

compared to any increase in price, 

initial charges, or maintenance expenses 

of the equipment likely to result from 

the standard. (42 U.S.C. 

6313(a)(6)(B)(ii)(I)–(II)) The effect of 

new or amended energy conservation 

standards on individual consumers 

usually involves a reduction in 

operating cost and an increase in 

purchase cost. To evaluate the economic 

impacts of potential energy conservation 


khammond on DSKJM1Z7X2PROD with PROPOSALS

I I I I I 
Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 30809 

13RSMeans Data from Gordian (2020) (Available 

at: https://www.rsmeansonline.com/) (Last 

Accessed: July 20, 2020). For details, please see the 

following records: B20301251800: Door, single, 

exterior fire door, ‘‘A’’ label, B20301252500: Door, 

double, exterior fire door, ‘‘A’’ label, 

C10201101600: Door, interior fire door, 

B20301251900: Door, double, aluminum, entrance, 

B20301251200: Door, single, aluminum, entrance. 

standards on individual consumers, in 

order to determine whether amended 

standards would be economically 

justified, DOE typically uses the 

following two metrics: 

• The LCC is the total consumer 

expense of equipment over the life of 

that equipment, consisting of total 

installed cost (manufacturer selling 

price, distribution chain mark-ups, sales 

tax, and installation costs) plus 

operating costs (expenses for energy use, 

maintenance, and repair). To compute 

the operating costs, DOE discounts 

future operating costs to the time of 

purchase and sums them over the 

lifetime of the equipment. 

• The PBP is the estimated amount of 

time (in years) it takes consumers to 

recover the increased purchase cost 

(including installation) of more-efficient 

equipment through lower operating 

costs. DOE calculates the PBP by 

dividing the change in purchase cost at 

higher efficiency levels by the change in 

annual operating cost for the year that 

amended or new standards are assumed 

to take effect. 

For any given efficiency level, DOE 

typically measures the change in LCC 

relative to the LCC in the no-newstandards case, which reflects the 

estimated efficiency distribution of 

equipment in the absence of new or 

amended energy conservation 

standards. In contrast, the PBP for a 

given efficiency level is measured 

relative to the baseline equipment. 

1. Installation Costs 

Installation cost includes labor, 

overhead, and any miscellaneous 

materials and parts needed to install the 

equipment. In response to the August 

2019 RFI, DOE received several 

comments related to installation issues 

associated with UFHWSTs with 

increased insulation thickness. BWC 

and AHRI stated that increasing the size 

of UFHWSTs by increasing the 

thickness of required insulation will 

lead to difficulties getting tanks through 

doorways and to their final locations in 

existing mechanical rooms. (BWC, No. 5 

at p. 2 and AHRI, No. 6 at p. 2) 

AHRI commented that reducing the 

storage volume of the tank itself is not 

a practical option because the most 

critical design feature of UFHWSTs is 

their storage volume. (AHRI, No. 6 at 

pp. 1–2) AHRI asserted that the 

predominant market for UFHWSTs are 

replacement installations, and again 

increased insulation would lead to 

difficulties with replacement because of 

space constraints in existing mechanical 

rooms. Additionally, BWC suggested 

that this could potentially necessitate 

the following changes: replacement of 

one UFHWST with two UFHWSTs, 

addition of mechanical rooms, or 

changes to system configurations. (BWC, 

No. 5 at p. 2) 

Feedback from manufacturer 

interviews conducted under NDAs also 

suggests that manufacturers are very 

concerned that increases in overall 

UFHWST dimensions due to increased 

insulation thickness could require 

modifications to existing doorways or 

mechanical rooms, in order to be able to 

replace existing tanks with a single tank 

of similar volume, which would 

significantly increase installation costs. 

In response to these comments from 

BWC and AHRI, DOE examined some of 

the potential installation costs (i.e., 

widening doorways that lead to the 

mechanical room and expanding the 

mechanical room itself). To estimate the 

costs of expanding doorways in order to 

allow UFHWSTs to pass through, DOE 

was able to examine the cost of door 

removal and reinstallation using data for 

exterior and interior door installations 

available in the RSMeans 2020 

Estimating Handbook Online.13 DOE 

examined the cost breakdown of 

installing new fire-rated doorways, both 

at 3 to 4-foot, and 6 to 7-foot width 

ranges, as well as interior passage doors 

at these same widths. For these doorway 

types, DOE did not use the entire 

installation values cited in the 

literature; rather, DOE only used the 

portions of the cost associated with the 

installation of existing frames and 

doors. DOE expects that comparable 

costs would be required to remove 

existing doors in a manner where they 

could be reinstalled without the need 

for new equipment, so for this estimate, 

the doorway installation cost were 

doubled to reflect both removal and 

reinstallation. Under this scenario, DOE 

found that door removal and 

reinstallation costs could potentially 

increase the cost of UFHWST 

installation by between $280 and $1720 

for every doorway requiring 

modification. DOE currently has no 

method of determining the average 

number of doorways that a UFHWST 

would need to pass through during the 

course of installation which increases 

the potential range of installation costs. 

For this NOPD, DOE was unable to 

find detailed data characterizing the 

costs of restructuring the mechanical 

room. However, DOE was able to 

examine other water- heating 

rulemakings with equipment with water 

storage characteristics where 

replacement installations could prove 

difficult. Specifically, DOE compared 

the magnitude of difference between the 

average, the 95th percentile, and 

maximum installation costs for the 

following baseline equipment as a proxy 

for potential customer impacts in 

extreme cases. DOE also does not 

currently have enough data indicating 

the percentage of UFHWST installations 

that could necessitate building 

modifications to get the UFHWST to its 

destination in the mechanical room, if 

tank dimensions were increased. 

However, the results in Table IV.8, 

while illustrative, are not exhaustive, 

and they show that the potential range 

of increased costs is significant, 

particularly for commercial equipment 

where the range of potential installation 

costs can be greater than 50 percent than 

the average in some extreme cases. It is 

expected that these costs would often be 

unavoidable because building owners 

are likely unable to substitute these 

tanks with tanks of alternative 

dimensions or volumes to meet 

operational needs and fit in existing 

spaces. 

TABLE IV.8—MAGNITUDE OF POTENTIAL INCREASE IN INSTALLATION COSTS

Equipment 

Installation cost 

($) 

Increase over mean 

(%) 

Mean 95thPercentile Maximum 95thPercentile Maximum 

Commercial-Duty Gas Storage Water Heater 14 ................. 812 1,225 2,432 51 199 

Residential-Duty Commercial Gas Storage Water Heater 15 678 1,001 2,088 48 208 

Commercial Electric Storage Water Heater 16 ..................... 1,054 1,325 1,773 26 68 


khammond on DSKJM1Z7X2PROD with PROPOSALS
30810 Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 

14U.S. Department of Energy, Energy Efficiency 

and Renewable Energy Office, Energy Conservation 

Standards for Commercial Water Heating 

Equipment, NOPR Analytical Spreadsheet: 

Commercial Water Heater (CWH) Life Cycle Cost 

(LCC) and Payback Period Analysis (April 20, 2016) 

(Available at: https://regulations.gov/document/ 

EERE-2014-BT-STD-0042-0013). See worksheet 

labelled: Forecast Cells. 

15 Ibid. 

16 Ibid. 

17U.S. Department of Energy, Energy Efficiency 

and Renewable Energy Office, Energy Efficiency 

Standards for Pool Heaters, Direct Heating 

Equipment and Water Heaters, 2010–04–06 Final 

Rule Analytical Tools (July 1, 2011) (Available at: 

https://www.regulations.gov/document?D=EERE2006-STD-0129-0148). See: 2010–03–26 Life Cycle 

Cost Electric Storage Water Heaters.xlsx. 

18U.S. Department of Energy, Energy Efficiency 

and Renewable Energy Office, Energy Efficiency 

Standards for Pool Heaters, Direct Heating 

Equipment and Water Heaters, 2010–04–06 Final 

Rule Analytical Tools (July 1, 2011) (Available at: 

https://www.regulations.gov/document?D=EERE2006-STD-0129–0148). See: 2010–03–26 Life Cycle 

Cost Gas-fired Storage Water Heaters.xlsx. 

19U.S. Department of Energy, Energy Efficiency 

and Renewable Energy Office, Energy Efficiency 

Standards for Pool Heaters, Direct Heating 

Equipment and Water Heaters, 2010–04–06 Final 

Rule Analytical Tools (July 1, 2011) (Available at: 

https://www.regulations.gov/document?D=EERE2006-STD-0129–0148). See: 2010–03–24 Life Cycle 

Cost Oil-fired Storage Water Heaters.xlsx. 

TABLE IV.8—MAGNITUDE OF POTENTIAL INCREASE IN INSTALLATION COSTS—Continued 

Equipment 

Installation cost 

($) 

Increase over mean 

(%) 

Mean 95thPercentile Maximum 95thPercentile Maximum 

Consumer Gas-fired Storage Water 17 ................................ 630 1,375 2,370 118 276 

Consumer Electric Storage Water Heaters 18 ..................... 288 402 498 40 73 

Consumer Oil-fired Storage Water Heaters 19 ..................... 1,974 2,283 2,910 16 47 

DOE recognizes that increasing 

installation costs can reduce, or even 

eliminate, the future economic 

consumer benefits from a potential new 

standard. Because of this, DOE 

tentatively agrees with the commenters 

that installation costs for certain 

UFHWST customers could include the 

removal and reinstallation of exterior 

and interior doorways, and in some 

extreme cases, it could require the 

restructuring of existing mechanical 

rooms to fit the new replacement 

equipment if the dimensions of 

UFHWSTs are increased. Furthermore, 

DOE tentatively agrees with the 

commenters that a small increase in 

tank dimensions in a potential new 

standards case could potentially 

disproportionately increase the 

installation costs for a fraction of 

consumers of replacement equipment. 

While the fraction of impacted 

consumers is uncertain, DOE is certain 

that there will be some consumers who 

will experience these higher installation 

costs. These higher installation costs for 

replacement equipment create 

uncertainty regarding the positive 

economic benefits for a potentially 

significant fraction of consumers from 

an amended standard for UFHWSTs. 

DOE requests data and information 

which can be used to estimate 

installation costs of UFHWSTs with 

modified dimensions. 

DOE requests information and data 

characterizing the types of buildings 

where installation difficulties are likely 

to occur and to lead to increased 

installation cost, as well as the 

frequency with which such installation 

problems may arise. 

DOE requests information and data 

characterizing the average installation 

costs for UFHWSTs at all different 

storage volumes. 

DOE requests information and data 

characterizing the circumstances that 

would drive the decision to potentially 

restructure an existing building spaces, 

including doorways and mechanical 

rooms, when installing a replacement 

UFHWST. For example, is the decision 

driven by a minimum building code 

requirement for door openings? 

2. Annual Energy Consumption 

DOE typically determines the annual 

energy consumption for equipment at 

different efficiency levels. DOE’s 

approach to determining the annual 

energy consumption of UFHWSTs is 

described in section IV.C of this 

document. In response to the August 

2019 RFI, A.O. Smith suggested that any 

potential energy savings resulting from 

changes to insulation thickness would 

be small and significantly outweighed 

by the costs that would be borne by 

commercial customers and 

manufacturers. (A.O. Smith, No. 8 at 

p. 2) 

As discussed in section V.A.1 of this 

document, DOE estimates that amended 

standards at the max-tech level would 

result in site energy savings (i.e., 

realized at the source of hot water by 

either a water heater or hot water supply 

boiler) of 0.017 quads over 30 years. 

However, as discussed in section IV.C.1 

of this document, even small 

adjustments to several critical inputs to 

the model could have a large impact on 

these results and could significantly 

alter the findings. For example, as 

explained previously, the inputs to the 

tank thermal loss model are primarily 

based on publicly-available data and 

information gathered during 

manufacturer interviews, but as 

discussed earlier, the results from this 

model underestimate losses as 

compared to those observed during 

testing of UFHWSTs that was previously 

done to evaluate the test procedure 

proposed for UFHWSTs in the May 

2016 CWH TP NOPR. These 

uncertainties would propagate through 

the cost-benefit analyses and could 

potentially significantly reduce the 

energy savings from amended standards. 

Therefore, DOE did not conduct an LCC 

and PBP analysis for this NOPD. 

E. Shipments Analysis 

DOE uses projections of annual 

equipment shipments to calculate the 

national impacts of potential amended 

or new energy conservation standards. 

The shipments model takes an 

accounting approach in tracking market 

shares of each equipment class and the 

vintage of units in the stock. Stock 

accounting uses equipment shipments 

as inputs to estimate the age distribution 

of in-service equipment stocks for all 

years. 

In response to the August 2019 RFI, 

AHRI stated that it would provide DOE 

with 2018 shipments data for UFHWST. 

(AHRI, No. 6 at p.1) However, no data 

were received, so DOE developed its 

own shipments estimates based on 

available data. 

To project shipments and equipment 

stocks for 2025 through the end of the 

30-year analysis period (2054), DOE 

used a stock accounting model. Future 

shipments are calculated based on 

projections in Annual Energy Outlook 

2021 (AEO 2021) (see section IV.E.3 of 

this document for further details). The 

stock accounting model keeps track of 

shipments and calculates replacement 

shipments based on the expected 

service lifetime of UFHWSTs and a 

Weibull distribution that identifies a 

percentage of units still in existence 

from a prior year that will fail and need 

to be replaced in the current year. 


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Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 30811 

20 Presently the 2015 edition of RECs is the most 

recent version. Energy Information Administration 

(EIA), 2015 Residential Energy Consumption 

Survey (RECS) (Available at: https://www.eia.gov/ 

consumption/residential/) (Last accessed April 4, 

2019). 

21 Presently, the 2012 edition of CBECs is the 

most recent version. Energy Information 

Administration (EIA), 2012 Commercial Building 

Energy Consumption Survey (CBECS) (Available at: 

https://www.eia.gov/consumption/commercial/) 

(Last accessed April 4, 2019). 

22 ‘‘District heating’’ is an underground 

infrastructure asset where thermal energy is 

provided to multiple buildings from a central 

energy plant or plants. In this context, it would be 

operated by local governments. 

23Energy Information Administration (EIA), 2014 

Manufacturing Energy Consumption Survey (MECS) 

(Available at: https://www.eia.gov/consumption/ 

manufacturing/data/2014/) (Last accessed April 4, 

2019). 

24Northwest Energy Efficiency Alliance, 2014 

Industrial Facilities Site Assessment: Report & 

Analytic Results, 2014 (Available at: https://

neea.org/img/documents/2014-industrial-facilitiesstock-assessment-final-report.pdf) (Last accessed 

May 3, 2021). 

25U.S. Census Bureau, All Sectors: Summary 

Statistics for the U.S., States, and Selected 

Geographies: 2017, Table EC1700BASIC, 2017 

(Available at: https://data.census.gov/cedsci/ 

table?q=31-33%3A%20Manufacturing&

hidePreview=false&tid=

ECNBASIC2017.EC1700BASIC&vintage=2017) (Last 

accessed: March 27, 2020). 

AHRI and A.O. Smith both stated that 

the UFHWST market is very small and 

often customized, and that the 

predominant market for UFHWSTs is 

for replacement equipment. (AHRI, No. 

6 at p. 2; A.O. Smith, No. 8 at pp.1) 

While this may be the case, DOE expects 

that manufacturers of this equipment 

will continue to seek out new markets 

and that some equipment will be sold 

into new construction. Therefore, the 

Department developed projections for 

this market as described in section 

IV.E.3 of this document. 

DOE’s approach begins with an 

estimate of the current stock of 

UFHWSTs. DOE uses an estimate of 

average UFHWST lifetime to derive the 

fraction of the stock that is replaced in 

each year. DOE then adds an estimate of 

new UFHWSTs installed in each year. 

1. Stock Estimates 

DOE investigated each sector that is 

presumed to operate UFHWSTs: 

Residential, commercial, and industrial. 

However, DOE was unable to find clear 

indicators of how many UFHWST are 

used by any of these sectors, so it 

developed sectoral stock estimates from 

publicly-available data, as discussed in 

the paragraphs that follow. 

a. Residential Stock 

To estimate the stock of UFHWSTs in 

the residential sector, DOE examined 

the Residential Energy Consumption 

Survey (RECS) 20 database. Although 

RECS does not contain specific fields 

that indicate the presence of a 

UFHWST, nor does RECS catalog 

specific water heating technologies, 

DOE was able to examine the available 

sample for buildings that would be 

likely to contain a UFHWST. DOE 

assumed that such a building would be 

characterized as follows: 

• A building with multiple residences 

(TYPEHUQ = 4 and 5), 

• where the hot water heater and 

storage tank are not in the apartment 

itself (H20HEATAPT = 2), and 

• where the hot water heater is of a 

type that is tankless, or on-demand. 

(WHEATSZ = 4) 

The results of a search of the RECS 

database using these assumptions 

yielded a sample of zero buildings. 

Based upon these results, DOE 

tentatively agrees with AHRI’s statement 

that UFHWST are primarily installed in 

industrial/commercial applications 

(AHRI, No. 6 at p. 2). Accordingly, DOE 

has tentatively concluded that the 

quantity of UFHWST installed in the 

residential sector is minimal and should 

not be considered for the purpose of this 

determination. 

b. Commercial Stock 

To estimate the stock of UFHWSTs in 

the commercial sector, DOE examined 

the Commercial Building Energy 

Consumption Survey (CBECS).21

Although CBECS does not contain 

specific fields that indicate the presence 

of a UFHWST, DOE was able to examine 

the available sample for buildings that 

would be likely to contain a UFHWST. 

DOE assumed that such a building 

would be characterized as follows: 

• A building with water heating 

equipment (WTHTEQ = 1), and 

• Where the main heating equipment 

is boilers inside (or adjacent to) the 

building that produce steam or hot 

water (MAINHT = 3). 

The results of a search of the CBECS 

database using these assumptions 

yielded a commercial sample of 325,089 

buildings in 2012. DOE could not find 

any data specifying the quantity of 

UFHWSTs per commercial building, so 

for this analysis, DOE assumed one 

UFWHST per building of all sizes. From 

this sample DOE also found that 99.2 

percent of these buildings use natural 

gas as their primary energy source for 

water heating, with the remaining 0.8 

percent of buildings using district water 

heating,22 electricity, heating oil, or 

other fuels. For purpose of this analysis, 

DOE considered 100 percent of 

commercial buildings to use natural gas 

to heat water. 

c. Industrial Stock 

DOE examined the industrial data 

source listed in the August 2019 ECS 

RFI and was not able to determine an 

appropriate stock sample from the 

highly aggregated data available.23 24

DOE understands that UFHWSTs are 

used to store potable hot water for 

human consumption and washing, not 

for industrial process water. Therefore, 

DOE assumed that the need for hot 

water storage would be the similar 

across both commercial and 

manufacturing sectors on a per-person 

basis. 

To estimate the stock of industrial 

consumers, DOE used the number of 

manufacturing employees from the 2017 

census.25 DOE first determined the ratio 

of UFHWSTs per commercial employee. 

DOE then used the ratio of the employee 

count from the commercial sample 

described in section IV.E.1.b of this 

document over the total number of 

commercial employees to represent the 

number of UFHWSTs in the commercial 

sector on a per-employee basis. DOE 

then applied this ratio to the total 

number of manufacturing employees 

from the 2017 census to produce a 

National stock estimate for the 

industrial sector. 

Table IV.9 presents the estimated 

stock of UFHWSTs in each sector, in 

2012. 

TABLE IV.9—ESTIMATED UFHWST 

STOCK (2012) 

Sector Number of 

units 

Weight 

(%) 

Residential ........ 0 0 

Commercial ....... 315,360 82 

Industrial ........... 71,361 18 

DOE requests comments generally 

regarding its stock analysis for 

UFHWSTs. 

DOE requests comment regarding its 

assumption that there would be only 

one UFWHST per building. 

DOE requests comment regarding its 

disaggregation of UFHWST stock by 

sector. 

DOE requests comment on its 

assumption that UFHWSTs are not used 

for industrial process hot water storage. 

2. Shipments for Replacement 

For this analysis DOE was unable to 

locate data on average lifetimes for 

UFHWSTs, and the Department likewise 

could not find primary data indicating 

average or maximum lifetimes for 

UFHSWTs. DOE understands that some 

of the causes of failure in other hot 

water storage tanks include corrosion, 

sediment build-up, and mechanical 


khammond on DSKJM1Z7X2PROD with PROPOSALS

I I 
30812 Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 

26 U.S. Energy Information Administration, 

Annual Energy Outlook (2021), Table 22, 

Commercial Sector Energy Consumption, 

Floorspace, Equipment Efficiency, and Distributed 

Generation (Available at: https://www.eia.gov/ 

outlooks/aeo/data/browser/#/?id=32- 

AEO2021&cases=ref2021&sourcekey=0). 

27 U.S. Energy Information Administration, 

Annual Energy Outlook (2021), Table 23, Industrial 

Sector Macroeconomic Indicators (Available at: 

https://www.eia.gov/outlooks/aeo/data/browser/#/ 

?id=34- AEO2021&cases=ref2021&sourcekey=0). 

failures. UFHWSTs are relatively simple 

equipment when compared to storagetype water heaters that include heating 

elements or a fossil-fuel burner with a 

storage tank. The simplicity of 

UFHWSTs would limit the likelihood of 

mechanical failure as compared to a 

storage-type water heater, but they can 

still fail due to corrosive or sediment 

build-up. Electric storage water heaters 

that use electric resistance elements for 

heating are likewise relatively simple 

equipment, whereas gas-fired storage 

water heaters can be more complex, 

because they typically require an 

ignition system, burner, combustion 

fans (in some cases), associated 

combustion controls, and flue gas 

venting system. The mechanical 

simplicity of electric storage water 

heaters lends itself to a failure mode 

related to the storage tank component of 

the water heating package, which would 

be expected to be analogous to the 

typical failure mode for an UFHWST. 

For this analysis, DOE used the average 

lifetime for commercial electric storage 

water heaters (i.e., 12 years) as a proxy 

for UFHWST lifetime. In the TSD for 

DOE’s May 2016 CWH ECS NOPR (81 

FR 34440), the average lifetime for 

commercial electric hot water storage 

tanks was estimated to be 12 years. 

Based on this average lifetime, DOE 

assumed an 8 percent per year 

replacement rate for UFHWSTs. 

DOE requests comment on its 

assumption of a 12-year lifetime for 

UFHWSTs similar to commercial 

electric hot water storage tanks. 

3. Shipments for New Construction 

To project shipments of UFHWSTs for 

new construction, DOE relied on the 

trends available from the AEO 2021. 

DOE used the Commercial Floorspace 

and Macro Indicators Employment 

Manufacturing trends to project new 

construction for the commercial and 

industrial sectors, respectively.26 27 DOE 

estimated a saturation rate for each 

equipment type using building and 

equipment stock values. The saturation 

rate was applied in each year, yielding 

shipments to new buildings. 

DOE requests comment on its use of 

AEO 2021 trends as a scaler to project 

shipments to new construction. 

4. Estimated Shipments 

Table IV.10 presents the estimated 

UFHWST shipments in selected years. 

TABLE IV.10—SHIPMENTS RESULTS

FOR UFHWSTS (UNITS) 

Year Shipments 

2025 ...................................... 18,292 

2030 ...................................... 19,240 

2040 ...................................... 21,244 

2050 ...................................... 23,208 

2060 ...................................... 0 

a. Distribution of Shipments by 

UFHWST Storage Volume 

Table IV.11 presents the estimated 

distribution of UFHWST shipments by 

the storage volume ranges specified in 

section IV.B.2 of this document. DOE 

estimated these values through 

examination of capacity counts in 

existing trade literature and DOE’s 

CCMS database. DOE assumes that this 

distribution is static and does not 

change over time. 

TABLE IV.11—DISTRIBUTION OF SHIPMENTS BY UFHWST STORAGE VOLUME (GAL) 

Capacity Range 0 to 100 

(percent) 

101 to 250 

(percent) 

251 to 500 

(percent) 

501 to 1000 

(percent) 

1001 to 2000 

(percent) 

2001 to 5000 

(percent) 

>5000 

(percent) 

Market Share ............... 3 11 23 26 20 16 1 

DOE requests comment on its 

distribution of shipments by storage 

volume, and on its assumption that the 

distribution of shipments by storage 

volume does not change over time. 

5. Additional Sources of Uncertainty 

DOE recognizes that the market for 

UFHWSTs is a relatively highly 

customized and low-volume shipments 

market. DOE’s review of publiclyavailable information indicates that 

annual shipments through 2030 will be 

below 20,000 units (see the previous 

section for additional details). 

Additionally, in response to the August 

2019 RFI, BWC submitted a list of over 

200 companies which it identified as 

UFHWST manufacturers, which 

underscores the low-volume nature of 

the UFHWST industry. (BWC, No. 5 at 

p.2) DOE reviewed these companies and 

found many to be custom fabrication/ 

welding shops or producers of vessels 

for niche industry processes such as 

chemical mixing or fuel storage. 

Although most of the manufacturers 

listed by BWC may theoretically be 

capable of manufacturing UFHWSTs, 

DOE did not find evidence that these 

businesses advertise or market 

UFHWSTs. However, DOE was able to 

confirm that some of the companies 

listed by BWC manufacture UFHWSTs, 

and DOE included these manufacturers 

in its list of UFHWST manufacturers. In 

total, DOE has identified 48 UFHWST 

manufacturers, 37 of which are small 

domestic manufacturers. 

Due to the niche nature of this 

marketplace, it is difficult to accurately 

predict how the market would respond 

to amended standards (e.g. whether any 

manufacturers would face 

disproportionately high conversion 

costs, what changes may result to the 

distribution of tank sizes sold, if 

consumers would select different 

equipment to meet their water heating 

needs, or whether manufacturers might 

consolidate or exit the market). These 

uncertainties may substantially impact 

the findings if DOE were to complete a 

full economic impact analysis of 

amended standards for UFHWSTs or 

estimate the cost-effectiveness of a 

more-stringent standard. 

F. National Impact Analysis 

DOE conducted an NIA that assesses 

the NES in terms of total site energy 

savings that would be expected to result 

from new or amended standards at 

specific efficiency levels. DOE did not 

assess the net present value (NPV) of the 

total costs and benefits experienced by 

consumers as part of the NIA because of 

the lack of an LCC analysis as 

previously discussed. DOE calculates 

the NES for the potential standard levels 

considered based on projections of 

annual equipment shipments, along 

with the annual energy consumption 

from the energy use analysis. For the 

present analysis, DOE projected the site 

energy savings over the lifetime of 

UFHWSTs sold from 2025 through 

2054. 


khammond on DSKJM1Z7X2PROD with PROPOSALS
Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 30813 

28 See: https://www.regulations.doe.gov/ccms. 29 While there is a wide range of equipment that 

building owners can use to produce hot water, for 

this analysis, DOE assumed that 100 percent of all 

hot water is produced by a hot water supply boiler. 

See section IV.E.1.b of this document for details. 

30 Available at: https://www.regulations.gov/ 

document?D=EERE-2014-BT-STD-0042-0016 (Last 

accessed: April 8, 2020). 31 U.S. Energy Information Administration, 

Annual Energy Outlook (2021), Table 22, 

Commercial Sector Energy Consumption, 

Floorspace, Equipment Efficiency, and Distributed 

Generation (Available at: https://www.eia.gov/ 

outlooks/aeo/data/browser/#/?id=32- 

AEO2021&cases=ref2021&sourcekey=0) (Last 

accessed April 23, 2021). 

DOE evaluates the effects of amended 

standards at the national level by 

comparing a case without such 

standards (referred to as the no-newstandards case) with standards-case 

projections that characterize the market 

for each UFHWST class if DOE were to 

adopt amended standards at the 

specified energy efficiency levels for 

that class. As discussed in the 

subsections that follow, this analysis 

requires an examination of both the 

efficiency of the UFHWST, as well as 

the efficiency of the appliance 

supplying heated water to that tank. 

1. Energy Efficiency Distribution in the 

No-New-Standards Case 

DOE received limited information 

regarding the efficiency range of 

UFHWSTs distributed in commerce in 

response to its request for comment in 

the August 2019 ECS RFI. BWC stated 

that it is appropriate to assume that for 

this analysis, all UFHWST have R–12.5 

insulation (i.e., that they meet the 

minimum R-value of 12.5 currently 

required by ASHRAE 90.1). (BWC, No. 

5 at p. 3) 

To estimate the fraction of equipment 

sold at or above the current standard, 

DOE examined the counts and R-values 

of the records in its Compliance 

Certification Management System 

(CCMS) database.28 DOE found that 

there were a minimal number of designs 

that related to the R-value efficiency 

levels determined in the engineering 

analysis, as demonstrated by Table 

IV.11. However, DOE notes that the data 

from the CCMS database is a count of 

models at a given efficiency and not a 

direct reflection of the number of units 

shipped at that efficiency level. When 

weighted as a function of shipments, the 

data shows that the vast majority of 

shipment are at baseline, as shown in 

Table IV.13. Consequently, DOE 

tentatively agrees with the statement 

from BWC and for this analysis assumed 

that almost all UFHWST across all 

capacities are at the baseline efficiency 

level, R–12.5. 

TABLE IV.12—FRACTIONS OF MODEL EFFICIENCY IN CCMS 

[% of records] 

Representative tank volume 

(gal.) 

EL 0 

(baseline) 

EL 1 EL 2 

R–12.5 R–15.62 R–18.75 

50 ................................................................................................................................................. 14 2 0 

175 ............................................................................................................................................... 21 1 0 

375 ............................................................................................................................................... 20 0 0 

750 ............................................................................................................................................... 18 0 0 

1500 ............................................................................................................................................. 21 0 0 

3500 ............................................................................................................................................. 2 0 0 

5000 ............................................................................................................................................. 0 0 0 

TABLE IV.13—FRACTION OF MODEL EFFICIENCIES AS A FUNCTION OF SHIPMENTS

[% of records] 

Representative tank volume (gal.) Weight 

EL 0 

(baseline) 

EL 1 EL 2 

R–12.5 R–15.62 R–18.75 

50 ..................................................................................................................... 0.03 3 0 0 

175 ................................................................................................................... 0.11 10 1 0 

375 ................................................................................................................... 0.23 23 0 0 

750 ................................................................................................................... 0.26 26 0 0 

1500 ................................................................................................................. 0.20 20 0 0 

3500 ................................................................................................................. 0.16 16 0 0 

5000 ................................................................................................................. 0.01 1 0 0

DOE requests comment regarding its 

applied efficiency distribution that 99 

percent of all units sold are currently at 

baseline (R–12.5). 

2. Hot Water Supply Boiler Efficiency 

Trend 

As stated previously, a potential 

standard increasing the insulation rating 

of UFWHST equipment would reduce 

thermal losses, which would in turn 

reduce the energy used by a building’s 

hot water supply equipment to provide 

hot water.29 Determining the impact of 

reduced UFHWST losses on the 

connected boiler(s) requires an estimate 

of the boiler efficiency. To estimate the 

efficiency of boiler systems, DOE used 

the No-New-Standards Case (EL0) 

efficiency distribution data from the 

May 2016 CWH ECS NOPR30 to 

calculate a single, market-weighted, 

average efficiency, which is 84.4 percent 

in 2016. For years beyond 2016 and 

future years through 2050, DOE used the 

AEO 2021 data series ‘‘Commercial: 

Stock Average Efficiency: Water 

Heating: Natural Gas: Reference case’’ to 

project the efficiency trend of hot-water 

supply boilers.31 DOE assumed no 

increase in boiler efficiency after 2050 

(i.e., the end date for the AEO 2021 


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32 U.S. Office of Management and Budget, 

Circular A–4: Regulatory Analysis (Sept. 17, 2003) 

(Available at: https://

obamawhitehouse.archives.gov/omb/circulars_

a004_a-4/). 

33 Under 42 U.S.C. 6313(a)(6)(C)(i) and (iv), EPCA 

requires DOE to review its standards for covered 

ASHRAE equipment every 6 years, and it requires 

a 3-year period after any new standard is 

promulgated before compliance is required, except 

that in no case may any new standards be required 

within 6 years of the compliance date of the 

previous standards. If DOE makes a determination 

that amended standards are not needed, it must 

conduct a subsequent review within three years 

following such a determination. (42 U.S.C. 

6313(a)(6)(C)(iii)(II)) Furthermore, if ASHRAE acts 

to amend ASHRAE Standard 90.1 for any of the 

enumerated equipment covered by EPCA, DOE is 

triggered to consider and adopt the amended 

ASHRAE levels, unless the Department has clear 

and convincing evidence to support more-stringent 

standard levels, which would result in significant 

additional energy savings and be technologically 

feasible and economically justified. (42 U.S.C. 

6313(a)(6)(A)(ii)) If DOE adopts the amended 

ASHRAE levels, compliance with amended Federal 

energy conservation standards would be required 

either two or three years after the effective date of 

the ASHRAE Standard 90.1 amendments 

(depending upon the equipment type in question). 

However, if DOE adopts more-stringent standards 

pursuant to the ASHRAE trigger, compliance with 

such standards would be required four years after 

publication of a final rule. (42 U.S.C. 6313(a)(6)(D)) 

As DOE is evaluating the need to amend the 

standards, the sensitivity analysis is based on the 

review timeframe associated with amended 

standards. While adding a 6-year review to the 3- 

year compliance period adds up to 9 years, DOE 

notes that it may undertake reviews at any time 

within the 6-year period and that the 3-year 

compliance date may yield to the 6-year backstop. 

A 9-year analysis period may not be appropriate 

given the variability that occurs in the timing of 

standards reviews and the fact that for some 

equipment, the compliance period may be 

something other than 3 years. 

analysis). This efficiency trend is shown 

in Table IV.14. 

TABLE IV.14—AVERAGE STOCK EFFICIENCIES OF HOT-WATER SUPPLY

BOILERS FROM 2025–2050 

Year Efficiency 

(%) 

2025 ...................................... 91.5 

2030 ...................................... 93.1 

2035 ...................................... 94.2 

2040 ...................................... 94.8 

2045 ...................................... 95.1 

2050 ...................................... 95.3 

G. Discussion of Other Comments 

Received 

In response to the August 2019 RFI, 

DOE received several comments in 

support of the current efficiency 

standard. BWC stated that the current 

efficiency requirement (a minimum 

insulation value of R–12.5) is an 

appropriate baseline efficiency level. 

(BWC, No. 5 at p. 2) Similarly, AHRI 

recommended that DOE maintain the 

current minimum insulation 

requirement of R–12.5. (AHRI, No. 6 at 

p. 2) BWC and A.O. Smith also said that 

there have not been significant market 

changes since their last energy 

conservation standard change and that a 

revised standard would not result in 

significant energy savings. (BWC, No. 5 

at p. 2; and A.O. Smith, No. 8 at p. 2) 

Additionally, BWC submitted 

comments related to the proposed 

manufacturer mark-up and the 

distribution channels used to 

characterize the UFHWST market in the 

August 2019 RFI. (BWC, No. 5 at p. 2) 

A.O. Smith commented that the 

majority of UFHWSTs are sold as 

replacement units and stated that major 

redesigns of existing product lines are 

very uncommon and potentially costprohibitive. (A.O. Smith, No. 8 at p. 2) 

As discussed previously, certain 

economic analyses were not conducted 

for this NOPD because it was 

determined they would be of limited 

use due to the lack of data and high 

degree of uncertainty regarding the 

inputs to those analyses. Furthermore, 

an MIA was also not conducted because 

of the lack of ‘‘clear and convincing’’ 

evidence that amended standards would 

be economically justified or result in 

significant conservation of energy. If 

DOE later determines that amended 

standards are warranted, these 

comments will be revisited. 

V. Analytical Results and Conclusions 

The following section addresses the 

results from DOE’s analyses with 

respect to the considered energy 

conservation standards for UFHWSTs. It 

addresses the ELs examined by DOE and 

the projected site energy savings of each 

of these levels. As discussed previously, 

certain economic analyses were not 

conducted for this NOPD because it was 

determined they would be of limited 

value due to the lack of data and high 

degree of uncertainty of the inputs to 

those analyses. 

A. National Impact Analysis 

This section presents DOE’s estimates 

of the site NES that would result from 

each of the ELs considered as potential 

amended standards. 

1. Significance of Energy Savings 

To estimate the energy savings 

attributable to potential amended 

standards for UFHWSTs, DOE compared 

their energy consumption under the nonew-standards case to their anticipated 

energy consumption under each EL. The 

savings are measured over the entire 

lifetime of equipment purchased in the 

30-year period that begins in the year of 

anticipated compliance with amended 

standards (2025–2054). Table V.1 

presents DOE’s projections of the site 

NES for each EL considered for 

UFHWSTs. The savings were calculated 

using the approach described in section 

IV.C of this document. 

TABLE V.1—CUMULATIVE NATIONAL

ENERGY SAVINGS FOR UFHWSTS; 

30 YEARS OF SHIPMENTS

[2025–2054] 

Efficiency level 

1 2 

Site Energy (quads) .. 0.011 0.017 

Percent Savings Over 

Baseline (%) .......... 15% 26% 

OMB Circular A–4 32 requires 

agencies to present analytical results, 

including separate schedules of the 

monetized benefits and costs that show 

the type and timing of benefits and 

costs. Circular A–4 also directs agencies 

to consider the variability of key 

elements underlying the estimates of 

benefits and costs. For this proposed 

determination, DOE undertook a 

sensitivity analysis using 9 years, rather 

than 30 years, of equipment shipments. 

The choice of a 9-year period is a proxy 

for the timeline in EPCA for the review 

of certain energy conservation standards 

and potential revision of and 

compliance with such revised 

standards.33 The review timeframe 

established in EPCA is generally not 

synchronized with the equipment 

lifetime, equipment manufacturing 

cycles, or other factors specific to 

UFHWSTs. Thus, such results are 

presented for informational purposes 

only and are not indicative of any 

change in DOE’s analytical 

methodology. The NES sensitivity 

analysis results based on a 9-year 

analytical period are presented in Table 

V.2. The impacts are counted over the 

lifetime of UFHWSTs purchased in 2025 

through 2033. 

TABLE V.2—CUMULATIVE NATIONAL

ENERGY SITE SAVINGS FOR

UFHWSTS; 9 YEARS OF SHIPMENTS

[2025–2034] 

Efficiency level 

1 2 

Site Energy (quads) .. 0.003 0.005 

Percent Savings Over 

Baseline (%) .......... 15% 26% 

2. Net Present Value of Consumer Costs 

and Benefits 

As discussed in section IV.D of this 

document, increasing the size of 


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UFHWSTs could necessitate alterations 

to doorways and mechanical rooms in 

certain replacement installations in 

order to get an UFHWST to its 

installation destination. Further, due to 

significant uncertainties regarding the 

costs of these alterations and the lack of 

data indicating the likelihood of such 

alterations being required, at this time, 

DOE is unable to estimate typical 

installation costs of UFHWSTs. 

Therefore, any analysis conducted by 

DOE regarding the LCC or PBP would be 

of limited value because of the lack of 

data and high degree of uncertainty of 

the inputs to those analyses, and as a 

result, DOE did not estimate the NPV of 

consumer costs and benefits. 

B. Proposed Determination 

After carefully considering the 

comments on the August 2019 RFI and 

the available data and information, DOE 

has tentatively determined that the 

energy conservation standards for 

UFHWSTs do not need to be amended, 

for the reasons explained in the 

paragraphs immediately following. DOE 

will consider all comments received on 

this proposed determination prior to 

issuing the next document in this 

rulemaking proceeding. 

EPCA specifies that for any 

commercial and industrial equipment 

addressed under 42 U.S.C. 

6313(a)(6)(A)(i), including UFHWSTs, 

DOE may prescribe an energy 

conservation standard more stringent 

than the level for such equipment in 

ASHRAE Standard 90.1 only if ‘‘clear 

and convincing evidence’’ shows that a 

more-stringent standard would result in 

significant additional conservation of 

energy and is technologically feasible 

and economically justified. (42 U.S.C. 

6313(a)(6)(C)(i); 42 U.S.C. 

6313(a)(6)(A)(ii)(II)) The ‘‘clear and 

convincing’’ evidentiary threshold 

applies both when DOE is triggered by 

ASHRAE action and when DOE 

conducts a six-year- lookback 

rulemaking, with the latter being the 

basis for the current proceeding. 

Because an analysis of potential costeffectiveness and energy savings first 

require an evaluation of the relevant 

technology, DOE first discusses the 

technological feasibility of amended 

standards. DOE then evaluates the 

energy savings potential and costeffectiveness of potential amended 

standards. 

1. Significant Conservation of Energy 

EPCA also mandates that DOE 

consider whether amended energy 

conservation standards for UFHWSTs 

would result in result in significant 

additional conservation of energy. (42 

U.S.C. 6313(a)(6)(C)(i); 42 U.S.C. 

6313(a)(6)(A)(ii)(II)) 

In the present case, DOE estimates 

that amended standards for UFHWST 

would result in energy savings of 0.011 

quads at EL 1 and 0.017 quads at EL 2 

(the max-tech level) over a 30-year 

analysis period (2025–2054), as realized 

by the connected hot-water supply 

boiler. However, as discussed in section 

IV.C.3 of this document, DOE has been 

unable to validate the results of the 

thermal loss model used for its analysis 

of energy savings, and consequently, 

there is considerable uncertainty 

regarding the accuracy and validity of 

the projected energy savings generated 

by that calculated model. Thus, DOE 

has tentatively determined that it lacks 

clear and convincing evidence that 

amended energy conservation standards 

for UFHWSTs would result in 

significant additional conservation of 

energy. (See results in Table V.1.) 

2. Technological Feasibility 

EPCA mandates that DOE consider 

whether amended energy conservation 

standards for UFHWSTs would be 

technologically feasible. (42 U.S.C. 

6313(a)(6)(C)(i); 42 U.S.C. 

6313(a)(6)(A)(ii)(II)) DOE has tentatively 

determined that increasing the thickness 

of insulation by up to 1 inch would 

improve the efficiency of UFHWSTs. As 

discussed in section IV.B.1 of this 

document, this increase in insulation 

thickness can be achieved for jacketed 

UFHWSTs without resulting in a 

decrease in the insulative properties of 

the foam. However, the potential for a 

decrease in insulative value of foam as 

the thickness increases above 3 inches 

thick, which results from changes in 

foam density, adds uncertainty to the Rvalues achievable by higher levels of 

increased insulation thicknesses. 

Increasing the thickness of insulation by 

up to 1 inch is achievable with the same 

insulation processes currently used in 

commercially-available jacketed 

UFHWSTs, and, therefore, would be 

technologically feasible. (See section 

IV.A.3 of this document for further 

information.) Hence, DOE has 

tentatively determined that amended 

energy conservation standards for 

UFHWSTs would be technologically 

feasible. 

3. Economic Justification 

In determining whether a standard is 

economically justified, the Secretary 

must determine whether the benefits of 

the standard exceed its burdens, 

considering to the greatest extent 

practicable the seven statutory factors 

discussed previously (see section II.A of 

this document). (42 U.S.C. 

6313(a)(6)(C)(i); 42 U.S.C. 

6313(a)(6)(B)(ii)(I)–(VII)) 

One of those seven factors is the 

savings in operating costs throughout 

the estimated average life of the product 

in the type (or class) compared to any 

increase in the price, initial charges, or 

maintenance expenses of the products 

that are likely to result from the 

standard. (42 U.S.C. 6313(a)(6)(C)(i); 42 

U.S.C. 6313(a)(6)(B)(ii)(II)) This factor is 

typically assessed using the LCC and 

PBP analysis, as well as the NPV. 

However, as discussed in sections IV.D 

and V.A.2 of this document, DOE was 

unable to calculate the LCC, PBP, and 

NPV of amended standards, because 

significant uncertainties in the inputs to 

these analyses would result in 

significant uncertainties in the results. 

Consequently, DOE could not develop 

economic analyses that would provide 

‘‘clear and convincing’’ evidence that 

amended standards are economically 

justified. 

4. Summary 

Based on the reasons stated in the 

foregoing discussion, DOE is proposing 

to determine that the energy 

conservation standards for unfired hot 

water storage tanks do not need to be 

amended, having initially determined 

that it lacks ‘‘clear and convincing’’ 

evidence that amended standards would 

be economically justified or result in 

significant additional conservation of 

energy. DOE will consider and respond 

to all comments received on this 

proposed determination in issuing any 

final determination. 

VI. Procedural Issues and Regulatory 

Review 

A. Review Under Executive Order 12866 

The Office of Management and Budget 

(OMB) has determined that this 

proposed determination does not 

constitute a ‘‘significant regulatory 

action’’ under section 3(f) of Executive 

Order (E.O.) 12866, ‘‘Regulatory 

Planning and Review,’’ 58 FR 51735 

(Oct. 4, 1993). Accordingly, this action 

was not subject to review under the 

Executive Order by the Office of 

Information and Regulatory Affairs 

(OIRA) at OMB. 

B. Review Under the Regulatory 

Flexibility Act 

The Regulatory Flexibility Act (5 

U.S.C. 601 et seq.) requires preparation 

of an initial regulatory flexibility 

analysis (IRFA) for any rule that by law 

must be proposed for public comment, 

unless the agency certifies that the rule, 

if promulgated, will not have a 

significant economic impact on a 


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34 U.S. Department of Energy Compliance 

Certification Management System, available at: 

https://www.regulations.doe.gov/ccms. 

substantial number of small entities. As 

required by E.O. 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 

rulemaking process. 68 FR 7990. DOE 

has made its procedures and policies 

available on the Office of the General 

Counsel’s website (http://energy.gov/gc/ 

office-general-counsel). 

The Small Business Administration 

(SBA) considers a business entity to be 

a small business, if, together with its 

affiliates, it employs less than a 

threshold number of workers specified 

in 13 CFR part 121. The size standards 

and codes are established by the 2017 

North American Industry Classification 

System (NAICS). 

Unfired hot water storage tank 

manufacturers are classified under 

NAICS code 333318, ‘‘Other 

Commercial and Service Industry 

Machinery Manufacturing.’’ The SBA 

sets a threshold of 1,000 employees or 

fewer for an entity to be considered as 

a small business in this category. DOE 

has conducted a focused inquiry into 

small business manufacturers of the 

equipment covered by this rulemaking. 

The Department used available public 

information to identify potential small 

manufacturers. DOE accessed the 

Compliance Certification Database 34 to 

create a list of companies that import or 

otherwise manufacture the unfired hot 

water storage tanks covered by this 

proposal. Using these sources, DOE 

identified a total of 48 distinct 

manufacturers of unfired hot water 

storage tanks. Of these manufacturers, 

DOE identified 37 manufacturers that 

are potential small businesses. 

DOE reviewed this proposed 

determination under the provisions of 

the Regulatory Flexibility Act and the 

policies and procedures published on 

February 19, 2003. Because DOE is 

proposing not to amend standards for 

UFHWSTs, if adopted, the 

determination would not amend any 

energy conservation standards. On the 

basis of the foregoing, DOE certifies that 

the proposed determination, if adopted, 

would not have a ‘‘significant economic 

impact on a substantial number of small 

entities.’’ Accordingly, DOE has not 

prepared an IRFA for this proposed 

determination. DOE will transmit this 

certification and supporting statement 

of factual basis to the Chief Counsel for 

Advocacy of the Small Business 

Administration for review under 5 

U.S.C. 605(b). 

C. Review Under the Paperwork 

Reduction Act 

This proposed determination, which 

proposes to determine that amended 

energy conservation standards for 

UFHWSTs are unneeded under the 

applicable statutory criteria, would 

impose no new informational or 

recordkeeping requirements. 

Accordingly, OMB clearance is not 

required under the Paperwork 

Reduction Act. (44 U.S.C. 3501 et seq.) 

D. Review Under the National 

Environmental Policy Act of 1969 

DOE is analyzing this proposed action 

in accordance with the National 

Environmental Policy Act of 1969 

(NEPA) and DOE’s NEPA implementing 

regulations (10 CFR part 1021). DOE’s 

regulations include a categorical 

exclusion for actions which are 

interpretations or rulings with respect to 

existing regulations. 10 CFR part 1021, 

subpart D, appendix A4. DOE 

anticipates that this action qualifies for 

categorical exclusion A4 because it is an 

interpretation or ruling in regard to an 

existing regulation and otherwise meets 

the requirements for application of a 

categorical exclusion. See 10 CFR 

1021.410. DOE will complete its NEPA 

review before issuing the final action. 

E. Review Under Executive Order 13132 

E.O. 13132, ‘‘Federalism,’’ 64 FR 

43255 (August 10, 1999), imposes 

certain requirements on Federal 

agencies formulating and implementing 

policies or regulations that preempt 

State law or that have Federalism 

implications. The Executive Order 

requires agencies to examine the 

constitutional and statutory authority 

supporting any action that would limit 

the policymaking discretion of the 

States and to carefully assess the 

necessity for such actions. The 

Executive Order also requires agencies 

to have an accountable process to 

ensure meaningful and timely input by 

State and local officials in the 

development of regulatory policies that 

have Federalism implications. On 

March 14, 2000, DOE published a 

statement of policy describing the 

intergovernmental consultation process 

it will follow in the development of 

such regulations. 65 FR 13735. DOE has 

examined this proposed determination 

and has tentatively determined that it 

would not have a substantial direct 

effect on the States, on the relationship 

between the national government and 

the States, or on the distribution of 

power and responsibilities among the 

various levels of government. EPCA 

governs and prescribes Federal 

preemption of State regulations as to 

energy conservation for the equipment 

that is the subject of this proposed 

determination. States can petition DOE 

for exemption from such preemption to 

the extent, and based on criteria, set 

forth in EPCA. (See 42 U.S.C. 6316(a) 

and (b); 42 U.S.C. 6297) As this 

proposed determination would not 

amend the standards for UFHWSTs, 

there is no impact on the policymaking 

discretion of the States. Therefore, no 

action is required by E.O. 13132. 

F. Review Under Executive Order 12988 

With respect to the review of existing 

regulations and the promulgation of 

new regulations, section 3(a) of E.O. 

12988, ‘‘Civil Justice Reform,’’ imposes 

on Federal agencies the general duty to 

adhere to the following requirements: 

(1) Eliminate drafting errors and 

ambiguity; (2) write regulations to 

minimize litigation; (3) provide a clear 

legal standard for affected conduct 

rather than a general standard, and (4) 

promote simplification and burden 

reduction. 61 FR 4729 (Feb. 7, 1996). 

Regarding the review required by 

section 3(a), section 3(b) of E.O. 12988 

specifically requires that Executive 

agencies make every reasonable effort to 

ensure that the regulation: (1) Clearly 

specifies the preemptive effect, if any; 

(2) clearly specifies any effect on 

existing Federal law or regulation; (3) 

provides a clear legal standard for 

affected conduct while promoting 

simplification and burden reduction; (4) 

specifies the retroactive effect, if any; (5) 

adequately defines key terms, and (6) 

addresses other important issues 

affecting clarity and general 

draftsmanship under any guidelines 

issued by the Attorney General. Section 

3(c) of Executive Order 12988 requires 

Executive agencies to review regulations 

in light of applicable standards in 

section 3(a) and section 3(b) to 

determine whether they are met, or it is 

unreasonable to meet one or more of 

them. DOE has completed the required 

review and determined that, to the 

extent permitted by law, this proposed 

determination meets the relevant 

standards of E.O. 12988. 

G. Review Under the Unfunded 

Mandates Reform Act of 1995 

Title II of the Unfunded Mandates 

Reform Act of 1995 (UMRA) requires 

each Federal agency to assess the effects 

of Federal regulatory actions on State, 

local, and Tribal governments and the 

private sector. Public Law 104–4, sec. 

201 (codified at 2 U.S.C. 1531). For a 


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35 ‘‘Energy Conservation Standards Rulemaking 

Peer Review Report’’ (2007) (Available at: https:// 

energy.gov/eere/buildings/downloads/energyconservation-standards-rulemaking-peer-reviewreport-0). 

proposed regulatory action likely to 

result in a rule that may cause the 

expenditure by State, local, and Tribal 

governments, in the aggregate, or by the 

private sector of $100 million or more 

in any one year (adjusted annually for 

inflation), section 202 of UMRA requires 

a Federal agency to publish a written 

statement that estimates the resulting 

costs, benefits, and other effects on the 

national economy. (2 U.S.C. 1532(a), (b)) 

The UMRA also requires a Federal 

agency to develop an effective process 

to permit timely input by elected 

officers of State, local, and Tribal 

governments on a proposed ‘‘significant 

intergovernmental mandate,’’ and 

requires an agency plan for giving notice 

and opportunity for timely input to 

potentially affected small governments 

before establishing any requirements 

that might significantly or uniquely 

affect them. On March 18, 1997, DOE 

published a statement of policy on its 

process for intergovernmental 

consultation under UMRA. 62 FR 

12820. DOE’s policy statement is also 

available at https://energy.gov/sites/ 

prod/files/gcprod/documents/umra_

97.pdf. 

DOE examined this proposed 

determination according to UMRA and 

its statement of policy and determined 

that the proposed determination does 

not contain a Federal intergovernmental 

mandate, nor is it expected to require 

expenditures of $100 million or more in 

any one year by State, local, and Tribal 

governments, in the aggregate, or by the 

private sector. As a result, the analytical 

requirements of UMRA do not apply. 

H. Review Under the Treasury and 

General Government Appropriations 

Act, 1999 

Section 654 of the Treasury and 

General Government Appropriations 

Act, 1999 (Pub. L. 105–277) requires 

Federal agencies to issue a Family 

Policymaking Assessment for any rule 

that may affect family well-being. This 

proposed determination would not have 

any impact on the autonomy or integrity 

of the family as an institution. 

Accordingly, DOE has concluded that it 

is not necessary to prepare a Family 

Policymaking Assessment. 

I. Review Under Executive Order 12630 

Pursuant to E.O. 12630, 

‘‘Governmental Actions and Interference 

with Constitutionally Protected Property 

Rights,’’ 53 FR 8859 (March 15, 1988), 

DOE has determined that this proposed 

determination would not result in any 

takings that might require compensation 

under the Fifth Amendment to the U.S. 

Constitution. 

J. Review Under the Treasury and 

General Government Appropriations 

Act, 2001 

Section 515 of the Treasury and 

General Government Appropriations 

Act, 2001 (44 U.S.C. 3516 note) provides 

for Federal agencies to review most 

disseminations of information to the 

public under information quality 

guidelines established by each agency 

pursuant to general guidelines issued by 

OMB. OMB’s guidelines were published 

at 67 FR 8452 (Feb. 22, 2002), and 

DOE’s guidelines were published at 67 

FR 62446 (Oct. 7, 2002). Pursuant to 

OMB Memorandum M–19–15, 

Improving Implementation of the 

Information Quality Act (April 24, 

2019), DOE published updated 

guidelines which are available at: 

https://www.energy.gov/sites/prod/files/ 

2019/12/f70/DOE%20Final

%20Updated%20IQA

%20Guidelines%20Dec%202019.pdf. 

DOE has reviewed this NOPD under the 

OMB and DOE guidelines and has 

concluded that it is consistent with 

applicable policies in those guidelines. 

K. Review Under Executive Order 13211 

E.O. 13211, ‘‘Actions Concerning 

Regulations That Significantly Affect 

Energy Supply, Distribution, or Use,’’ 66 

FR 28355 (May 22, 2001), requires 

Federal agencies to prepare and submit 

to OIRA at OMB, a Statement of Energy 

Effects for any proposed significant 

energy action. A ‘‘significant energy 

action’’ is defined as any action by an 

agency that promulgates or is expected 

to lead to promulgation of a final rule, 

and that: (1) Is a significant regulatory 

action under Executive Order 12866, or 

any successor Executive Order; and (2) 

is likely to have a significant adverse 

effect on the supply, distribution, or use 

of energy, or (3) is designated by the 

Administrator of OIRA as a significant 

energy action. For any proposed 

significant energy action, the agency 

must give a detailed statement of any 

adverse effects on energy supply, 

distribution, or use should the proposal 

be implemented, and of reasonable 

alternatives to the action and their 

expected benefits on energy supply, 

distribution, and use. 

This proposed determination, which 

does not propose to amend energy 

conservation standards for UFHWSTs, is 

not a significant regulatory action under 

Executive Order 12866. Moreover, it 

would not have a significant adverse 

effect on the supply, distribution, or use 

of energy, nor has it been designated as 

a significant energy action by the 

Administrator at OIRA. Therefore, it is 

not a significant energy action, and 

accordingly, DOE has not prepared a 

Statement of Energy Effects. 

L. Review Under the Information 

Quality Bulletin for Peer Review 

On December 16, 2004, OMB, in 

consultation with the Office of Science 

and Technology Policy (OSTP), issued 

its Final Information Quality Bulletin 

for Peer Review (the Bulletin). 70 FR 

2664 (Jan. 14, 2005). The Bulletin 

establishes that certain scientific 

information shall be peer reviewed by 

qualified specialists before it is 

disseminated by the Federal 

Government, including influential 

scientific information related to agency 

regulatory actions. The purpose of the 

bulletin is to enhance the quality and 

credibility of the Government’s 

scientific information. Under the 

Bulletin, the energy conservation 

standards rulemaking analyses are 

‘‘influential scientific information,’’ 

which the Bulletin defines as ‘‘scientific 

information the agency reasonably can 

determine will have, or does have, a 

clear and substantial impact on 

important public policies or private 

sector decisions.’’ Id. at 70 FR 2667. 

In response to OMB’s Bulletin, DOE 

conducted formal peer reviews of the 

energy conservation standards 

development process and the analyses 

that are typically used and has prepared 

Peer Review report pertaining to the 

energy conservation standards 

rulemaking analyses.35 Generation of 

this report involved a rigorous, formal, 

and documented evaluation using 

objective criteria and qualified and 

independent reviewers to make a 

judgment as to the technical/scientific/ 

business merit, the actual or anticipated 

results, and the productivity and 

management effectiveness of programs 

and/or projects. DOE has determined 

that the peer-reviewed analytical 

process continues to reflect current 

practice, and the Department followed 

that process for considering amended 

energy conservation standards in the 

case of the present action. 

VII. Public Participation 

A. Participation in the Webinar 

The time and date of the webinar are 

listed in the DATES section at the 

beginning of this document. Webinar 

registration information, participant 

instructions, and information about the 

capabilities available to webinar 

participants will be published on DOE’s 


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30818 Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 

website: https://www1.eere.energy.gov/ 

buildings/appliance_standards/ 

standards.aspx?productid=36&

action=viewlive. Participants are 

responsible for ensuring their systems 

are compatible with the webinar 

software. 

B. Procedure for Submitting Prepared 

General Statements for Distribution 

Any person who has an interest in the 

topics addressed in this proposed 

rulemaking, or who is representative of 

a group or class of persons that has an 

interest in these issues, may request an 

opportunity to make an oral 

presentation at the webinar. Such 

persons may submit requests to speak 

by email to the Appliance and 

Equipment Standards Program, 

ApplianceStandardsQuestions@

ee.doe.gov. Persons who wish to speak 

should include with their request a 

computer file in WordPerfect, Microsoft 

Word, PDF, or text (ASCII) file format 

that briefly describes the nature of their 

interest in this rulemaking and the 

topics they wish to discuss. Such 

persons should also provide a daytime 

telephone number where they can be 

reached. 

Persons requesting to speak should 

briefly describe the nature of their 

interest in this proposed determination 

and provide a telephone number for 

contact. DOE requests persons selected 

to make an oral presentation to submit 

an advance copy of their statements at 

least two weeks before the webinar. At 

its discretion, DOE may permit persons 

who cannot supply an advance copy of 

their statement to participate, if those 

persons have made advance alternative 

arrangements with the Building 

Technologies Office. As necessary, 

requests to give an oral presentation 

should ask for such alternative 

arrangements. 

C. Conduct of the Webinar 

DOE will designate a DOE official to 

preside at the webinar and may also use 

a professional facilitator to aid 

discussion. The meeting will not be a 

judicial or evidentiary-type public 

hearing, but DOE will conduct it in 

accordance with section 336 of EPCA 

(42 U.S.C. 6306). A court reporter will 

be present to record the proceedings and 

prepare a transcript. DOE reserves the 

right to schedule the order of 

presentations and to establish the 

procedures governing the conduct of the 

webinar. There shall not be discussion 

of proprietary information, costs or 

prices, market share, or other 

commercial matters regulated by U.S. 

anti-trust laws. After the webinar and 

until the end of the comment period, 

interested parties may submit further 

comments on the proceedings and any 

aspect of the proposed determination. 

The webinar will be conducted in an 

informal, conference style. DOE will 

present summaries of comments 

received before the webinar, allow time 

for prepared general statements by 

participants, and encourage all 

interested parties to share their views on 

issues affecting this proposed 

determination. Each participant will be 

allowed to make a general statement 

(within time limits determined by DOE), 

before the discussion of specific topics. 

DOE will permit, as time permits, other 

participants to comment briefly on any 

general statements. 

At the end of all prepared statements 

on a topic, DOE will permit participants 

to clarify their statements briefly and 

comment on statements made by others. 

Participants should be prepared to 

answer questions by DOE and by other 

participants concerning these issues. 

DOE representatives may also ask 

questions of participants concerning 

other matters relevant to this proposed 

determination. The official conducting 

the webinar will accept additional 

comments or questions from those 

attending, as time permits. The 

presiding official will announce any 

further procedural rules or modification 

of the above procedures that may be 

needed for the proper conduct of the 

webinar. 

A transcript of the webinar will be 

included in the docket, which can be 

viewed as described in the Docket 

section at the beginning of this NOPD. 

In addition, any person may buy a copy 

of the transcript from the transcribing 

reporter. 

D. Submission of Comments 

DOE will accept comments, data, and 

information regarding this proposed 

determination no later than the date 

provided in the DATES section at the 

beginning of this proposed 

determination. Interested parties may 

submit comments, data, and other 

information using any of the methods 

described in the ADDRESSES section at 

the beginning of this document. 

Submitting comments via https://

www.regulations.gov. The https://

www.regulations.gov web page will 

require you to provide your name and 

contact information. Your contact 

information will be viewable to DOE 

Building Technologies staff only. Your 

contact information will not be publicly 

viewable except for your first and last 

names, organization name (if any), and 

submitter representative name (if any). 

If your comment is not processed 

properly because of technical 

difficulties, DOE will use this 

information to contact you. If DOE 

cannot read your comment due to 

technical difficulties and cannot contact 

you for clarification, DOE may not be 

able to consider your comment. 

However, your contact information 

will be publicly viewable if you include 

it in the comment itself or in any 

documents attached to your comment. 

Any information that you do not want 

to be publicly viewable should not be 

included in your comment, nor in any 

document attached to your comment. 

Otherwise, persons viewing comments 

will see only first and last names, 

organization names, correspondence 

containing comments, and any 

documents submitted with the 

comments. 

Do not submit to https://

www.regulations.gov information for 

which disclosure is restricted by statute, 

such as trade secrets and commercial or 

financial information (hereinafter 

referred to as Confidential Business 

Information (CBI)). Comments 

submitted through https://

www.regulations.gov cannot be claimed 

as CBI. Comments received through the 

website will waive any CBI claims for 

the information submitted. For 

information on submitting CBI, see the 

Confidential Business Information 

section. 

DOE processes submissions made 

through https://www.regulations.gov 

before posting. Normally, comments 

will be posted within a few days of 

being submitted. However, if large 

volumes of comments are being 

processed simultaneously, your 

comment may not be viewable for up to 

several weeks. Please keep the comment 

tracking number that https://

www.regulations.gov provides after you 

have successfully uploaded your 

comment. 

Submitting comments via email. 

Comments and documents submitted 

via email also will be posted to https:// 

www.regulations.gov. If you do not want 

your personal contact information to be 

publicly viewable, do not include it in 

your comment or any accompanying 

documents. Instead, provide your 

contact information in a cover letter. 

Include your first and last names, email 

address, telephone number, and 

optional mailing address. With this 

instruction followed, the cover letter 

will not be publicly viewable as long as 

it does not include any comments. 

Include contact information each time 

you submit comments, data, documents, 

and other information to DOE. No 

telefacsimiles (faxes) will be accepted. 

Comments, data, and other 

information submitted to DOE 


khammond on DSKJM1Z7X2PROD with PROPOSALS
Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 30819 

electronically should be provided in 

PDF (preferred), Microsoft Word or 

Excel, WordPerfect, or text (ASCII) file 

format. Provide documents that are not 

secured, that are written in English, and 

that are free of any defects or viruses. 

Documents should not contain special 

characters or any form of encryption 

and, if possible, they should carry the 

electronic signature of the author. 

Campaign form letters. Please submit 

campaign form letters by the originating 

organization in batches of between 50 to 

500 form letters per PDF or as one form 

letter with a list of supporters’ names 

compiled into one or more PDFs. This 

reduces comment processing and 

posting time. 

Confidential Business Information. 

Pursuant to 10 CFR 1004.11, any person 

submitting information that he or she 

believes to be confidential and exempt 

by law from public disclosure should 

submit via email two well-marked 

copies: One copy of the document 

marked ‘‘confidential’’ including all the 

information believed to be confidential, 

and one copy of the document marked 

‘‘non-confidential’’ with the information 

believed to be confidential deleted. DOE 

will make its own determination about 

the confidential status of the 

information and treat it according to its 

determination. 

It is DOE’s policy that all comments 

may be included in the public docket, 

without change and as received, 

including any personal information 

provided in the comments (except 

information deemed to be exempt from 

public disclosure). 

E. Issues on Which DOE Seeks Comment 

Although DOE welcomes comments 

on any aspect of this proposed 

determination, DOE is particularly 

interested in receiving comments and 

views of interested parties concerning 

the following issues: 

(1) DOE requests data and information 

related to achievable R-values of 

polyurethane foam insulation on 

jacketed UFHWSTs at thicknesses above 

3 inches. DOE also seeks comment on 

its understanding of the difficulties 

associated with applying more than 3 

inches of foam to jacketed UFHWSTs. 

(2) DOE seeks comment on the 

considered efficiency levels analyzed 

for UFHWSTs. Additionally, DOE seeks 

comment on its assumption that 

polyurethane foam has an R-value per 

inch of 6.25, up to a maximum 

thickness of 3 inches. 

(3) DOE requests comment on the 

inputs and assumptions used in its 

engineering analysis. In particular, DOE 

requests input on its choice of 

representative volumes, its assumptions 

about the typical coverage of various 

insulation materials, and its estimated 

R-values for each insulation material at 

each EL considered. 

(4) DOE requests comment on the 

appropriateness of its assumption 

regarding the use of a constant internal 

water temperature of 140 °F. 

(5) DOE requests comment on its 

assumption regarding the typical 

ambient temperatures for UFHWSTs 

installed indoors and outdoors. 

(6) DOE requests comment on its 

assumption that 10 percent of all 

UFHWST would be installed outdoors. 

DOE requests information on the typical 

capacities and R-values of outdoor 

equipment. 

(7) DOE requests comment on its 

assumption that outdoor installations 

would be limited to climate zones 1A, 

2A, and 2B. DOE requests information 

or data on the fraction of installations 

that occur within these, or other, 

climate zones. 

(8) DOE requests comment on its Tank 

Thermal Loss Model. 

(9) DOE requests data and information 

which can be used to estimate 

installation costs of UFHWSTs with 

modified dimensions. 

(10) DOE requests information and 

data characterizing the types of 

buildings where installation difficulties 

are likely to occur and to lead to 

increased installation cost, as well as 

the frequency with which such 

installation problems may arise. 

(11) DOE requests information and 

data characterizing the average 

installation costs for UFHWSTs at all 

different storage volumes. 

(12) DOE requests information and 

data characterizing the circumstances 

that would drive the decision to 

potentially restructure existing building 

spaces, including doorways and 

mechanical rooms, when installing a 

replacement UFHWST. For example, is 

the decision driven by a minimum 

building code requirement for door 

openings? 

(13) DOE requests comments 

generally regarding its stock analysis for 

UFHWSTs. 

(14) DOE requests comment regarding 

its assumption that there would be only 

one UFWHST per building. 

(15) DOE requests comment regarding 

its disaggregation of UFHWST stock by 

sector. 

(16) DOE requests comment on its 

assumption that UFHWSTs are not used 

for industrial process hot water storage. 

(17) DOE requests comment on its 

assumption of a 12-year lifetime for 

UFHWSTs similar to commercial 

electric hot water storage tanks. 

(18) DOE requests comment on its use 

of AEO 2021 trends as a scaler to project 

shipments to new construction. 

(19) DOE requests comment on its 

distribution of shipments by storage 

volume, and on its assumption that the 

distribution of shipments by storage 

volume does not change over time. 

(20) DOE requests comment regarding 

its applied efficiency distribution that 

99 percent of all units sold are currently 

at baseline (R–12.5). 

VIII. Approval of the Office of the 

Secretary 

The Secretary of Energy has approved 

publication of this notification of 

proposed determination. 

Signing Authority 

This document of the Department of 

Energy was signed on June 3, 2021, by 

Kelly Speakes-Backman, Principal 

Deputy Assistant Secretary and Acting 

Assistant Secretary for Energy Efficiency 

and Renewable Energy, pursuant to 

delegated authority from the Secretary 

of Energy. That document with the 

original signature and date is 

maintained by DOE. For administrative 

purposes only, and in compliance with 

requirements of the Office of the Federal 

Register, the undersigned DOE Federal 

Register Liaison Officer has been 

authorized to sign and submit the 

document in electronic format for 

publication, as an official document of 

the Department of Energy. This 

administrative process in no way alters 

the legal effect of this document upon 

publication in the Federal Register. 

Signed in Washington, DC, on June 3, 

2021. 

Treena V. Garrett, 

Federal Register Liaison Officer, U.S. 

Department of Energy. 

[FR Doc. 2021–11957 Filed 6–9–21; 8:45 am] 

BILLING CODE 6450–01–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2021–0459; Project 

Identifier MCAI–2021–00129–T] 

RIN 2120–AA64 

Airworthiness Directives; Gulfstream 

Aerospace LP Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for 


khammond on DSKJM1Z7X2PROD with PROPOSALS