Residential Water Heaters



Department of Energy

Manufacturers have been required to comply with the Department of Energy (DOE) energy conservation standards for residential water heaters since 1990. Residential water heaters are products that utilize oil, gas, or electricity to heat potable water for use upon demand for activities such as washing dishes or clothes, or bathing. Residential water heaters include storage type units that store heated water in an insulated tank and instantaneous type units that heat water on demand.


Ongoing Regulations
Energy Conservation Program for Consumer Products: Definitions for Residential Water Heaters

Summary: The Energy Policy and Conservation Act of 1975 (EPCA), as amended, prescribes energy conservation standards for various consumer products and certain commercial and industrial equipment, including residential water heaters. EPCA also requires the U.S. Department of Energy (DOE) to determine whether more-stringent, amended standards would be technologically feasible and economically justified, and would save a significant amount of energy. Accordingly, DOE established amended energy conservation standards for several classes of residential water heaters in an April 2010 final rule. DOE is amending its definitions pertaining to residential water heaters and to clarify the applicability of energy conservation standards for residential water heaters that are utilized as a secondary back-up heat source in solar-thermal water heating systems. Specifically, DOE is creating a definition for solar assisted fossil fuel storage water heater and solar assisted electric storage water heater and clarify that water heaters meeting these definitions are not subject to the amended energy conservation standards for residential water heaters established by the April 2010 final rule.

Type of Regulation: Energy Conservation Standard

Rulemaking Link: Rulemaking Webpage

Docket ID: EERE-2014-BT-STD-0045

UPDATES:

Comment Period Close Date: Closed

Where to Comment: N/A

AHRI Comments to Previous Stages of Rulemaking:

  • 2015-05-08 — AHRI comments on 2015-04-08 Energy Conservation Program for Consumer Products: Definitions for Residential Water Heaters
  • 2014-11-20 — AHRI Comments on 2014-10-21 Energy Conservation Program for Consumer Products

Staff Contact: Shannon Corcoran




Future Regulations

N/A




Current Efficiency Standards
Standard Level

Gas-fired (≤75 kBtu/h input capacity), oil-fired (≤105 kBtu/h input capacity), electric (≤12 kW input capacity), and tabletop (≤12 kW input capacity) storage water heaters as well as instantaneous gas-fired (<200 kBtu/h input capacity) and electric (≤12 kW input capacity) water heaters manufactured and distributed in commerce, as defined by 42 U.S.C. 6291(16), must meet the energy conservation standards specified in the Code of Federal Regulations, 10 CFR 430.32(d) as of January 20, 2004.



Table 1. Energy Conservation Standards for Residential Water Heaters

Product Class

Rated Storage Volume

Energy Factor

Gas-fired Water Heater

≥ 20 gal and ≤ 100 gal

0.67 — (0.0019*VS)

Oil-fired Water Heater

≤ 50 gal

0.59 — (0.0019*VS)

Electric Water Heater

≥ 20 gal and ≤ 120 gal

0.97 — (0.00132*VS)

Tabletop Water Heater

≥ 20 gal and ≤ 100 gal

0.93 — (0.00132*VS)

Instantaneous Gas-fired Water Heater

< 2gal

0.62 — (0.0019*VS)

Instantaneous Electric Water Heater

< 2 gal

0.93 — (0.00132*VS)

Vs: Rated Storage Volume — the water storage capacity of a water heater (in gallons).



For further guidance or to submit questions related to the implementation of this standard, visit the Guidance and Frequently Asked Questions page.

Amended Standard

(1) Water heaters. The energy factor of water heaters shall not be less than the following for products manufactured on or after the indicated dates.


Table 2. Amended Energy Conservation Standards for Residential Water Heaters

Product Class

Storage Volume

Energy Factor as of January 20, 2004

Energy Factor as of April 16, 2015

Gas-fired Storage Water Heater

≥ 20 gallons and ≤ 100 gallons

0.67-(0.0019 x Rated Storage Volume in gallons)

For tanks with a Rated Storage Volume at or below 55 gallons: EF = 0.675-(0.0015 × Rated Storage Volume in gallons).

For tanks with a Rated Storage Volume above 55 gallons: EF = 0.8012-(0.00078 × Rated Storage Volume in gallons).

Oil-fired Storage Water Heater

≤ 50 gallons

0.59-(0.0019 x Rated Storage Volume in gallons)

EF = 0.68-(0.0019 x Rated Storage Volume in gallons)

Electric Storage Water Heater

≥20 gallons and ≤120 gallons

0.97-(0.00132 x Rated Storage Volume in gallons)

For tanks with a Rated Storage Volume at or below 55 gallons: EF = 0.960-(0.0003 × Rated Storage Volume in gallons).

For tanks with a Rated Storage Volume above 55 gallons: EF = 2.057-(0.00113 × Rated Storage Volume in gallons).

Tabletop Water Heater

≥ 20 gallons and ≤ 120 gallons

0.93-(0.00132 x Rated Storage Volume in gallons)

EF = 0.93-(0.00132 x Rated Storage Volume in gallons).

Instantaneous Gas-fired Water Heater

< 2 gallons

0.62-(0.0019 x Rated Storage Volume in gallons)

EF = 0.82-(0.0019 x Rated Storage Volume in gallons).

Instantaneous Electric Water Heater

< 2 gallons

0.93-(0.00132 x Rated Storage Volume in gallons)

EF = 0.93-(0.00132 x Rated Storage Volume in gallons).


(2) Grid-enabled water heaters. Exclusions: The energy conservation standards shown in this paragraph do not apply to the following types of water heaters: gas-fired, oil-fired, and electric water heaters at or above 2 gallons storage volume and below 20 gallons storage volume; gas-fired water heaters above 100 gallons storage volume; oil-fired water heaters above 50 gallons storage volume; electric water heaters above 120 gallons storage volume; gas-fired instantaneous water heaters at or below 50,000 Btu/h; and grid-enabled water heaters.

(i) Energy factor -- The energy factor of grid-enabled water heaters, as of April 30, 2015, shall not be less than 1.06 —(0.00168 × Rated Storage Volume in gallons).

NOTE: The Rated Storage Volume equals the water storage capacity of a water heater, in gallons, as certified by the manufacturer.


Based on the final rule of the conversion factor, the minimum efficiency standards are as follows:

§ 430.32 Energy and water conservation standards and compliance dates.

(d) Water heaters. The uniform energy factor of water heaters shall not be less than the following:

 Product Class

Rated storage volume and input rating (if applicable)

Draw pattern

Uniform energy factor

Gas-fired Water Heater

≥ 20 gal and ≤ 55 gal

Very Small

0.3456 – (0.0020 × Vr)

Low

0.5982 – (0.0019 × Vr)

Medium

0.6483 – (0.0017 × Vr)

High

0.6920 – (0.0013 × Vr)

> 55 gal and ≤ 100 gal

Very Small

0.6470 – (0.0006 × Vr)

Low

0.7689 – (0.0005 × Vr)

Medium

0.7897 – (0.0004 × Vr)

High

0.8072 – (0.0003× Vr)

Oil-fired Storage Water Heater

≤ 50 gal

Very Small

0.2509 – (0.0012 × Vr)

Low

0.5330 – (0.0016 × Vr)

Medium

0.6078 – (0.0016 × Vr)

High

0.6815 – (0.0014 × Vr)

Electric Storage Water Heaters

≥ 20 gal and ≤ 55 gal

Very Small

0.8808 – (0.0008 × Vr)

Low

0.9254 – (0.0003 × Vr)

Medium

0.9307 – (0.0002 × Vr)

High

0.9349 – (0.0001 × Vr)

> 55 gal and ≤ 120 gal

Very Small

1.9236 – (0.0011 × Vr)

Low

2.0440 – (0.0011 × Vr)

Medium

2.1171 – (0.0011 × Vr)

High

2.2418 – (0.0011 × Vr)

Tabletop Water Heater

≥ 20 gal and ≤ 55 gal

Very Small

0.6323 – (0.0058 × Vr)

Low

0.9188 – (0.0031 × Vr)

Medium

0.9577 – (0.0023 × Vr)

High

0.9884 – (0.0016 × Vr)

Instantaneous Gas-fired Water Heater

< 2 gal and > 50,000 Btu/h

Very Small/Low

0.800.81

Medium

0.81

High

0.81

Instantaneous Electric Water Heater

≤ 2 gal

Very Small

0.91

Low

0.91

Medium

0.91

High

0.92

Grid-enabled Water Heater

≥ 75 gal

Very Small

1.0136 – (0.0028 × Vr)

Low

0.9984 – (0.0014 × Vr)

Medium

0.9853 – (0.0010 × Vr)

High

0.9720 – (0.0007 × Vr)




Current Test Procedures

To determine compliance with DOE standards, manufacturers must follow the test procedures specified at 10 CFR 430.32(d) for residential water heaters. The methods to conduct the test procedure are further specified in 10 CFR 430 Appendix E to Subpart B.

  • Final Rule: Correction, Federal Register, 80 FR 37953 (July 2, 2015)
  • Final Rule, Federal Register, 79 FR 40542 (July 11, 2014)
  • Docket No. EERE-2011-BT-TP-0042 contains notices, public comments, public meeting transcripts, and supporting documents.
  • Final Rule, Federal Register, 81 FR 96204 (December 29, 2016)
  • Docket No. EERE-2015-BT-TP-0007 contains notices, public comments, public meeting transcripts, and supporting documents.

For further guidance or to submit questions related to the implementation of this test procedure, visit the Guidance and Frequently Asked Questions page.




EPA Energy Star

Current Product Specifications:

Water Heaters Program Requirements Version 3.0


In Development:

There are no new versions currently in development.


Applying for Energy Star:

To qualify a new product, contact an EPA-recognized Certification Body (CB) to have the product's performance certified. A list of EPA-recognized CBs, as well as an overview of EPA's third-party certification procedures, is available at Third-Party Certification. AHRI is an EPA-recognized CB. Email AHRICert_EnergyStar@ahrinet.org for more information.


More Information:

Energy Star Water Heater Website