§ 431.110 Energy conservation standards and their effective dates.

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Title 10 CFR: Energy › Chapter II: DEPARTMENT OF ENERGY › Part 431: ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT › Subpart G: Commercial Water Heaters, Hot Water Supply Boilers and Unfired Hot Water Storage Tanks › § 431.110: § 431.110 Energy conservation standards and their effective dates.

This text was captured on Aug 14, 2026. It is a snapshot, not a live feed, so check the official code before relying on it.

Text

(a) Each commercial storage water heater, instantaneous water heater, and hot water supply boiler (excluding residential-duty commercial water heaters) must meet the applicable energy conservation standard level(s) as specified in the table to this paragraph. Any packaged boiler that provides service water that meets the definition of “commercial packaged boiler” in subpart E of this part, but does not meet the definition of “hot water supply boiler” in subpart G of this part, must meet the requirements that apply to it under subpart E of this part.

Table 1 to § 431.110(

a

)—Commercial Water Heater Energy Conservation Standards

Equipment

Size

Energy conservation standards

a

Minimum thermal

efficiency

(equipment

manufactured on

and after October 9, 2015)

(%)

Minimum thermal

efficiency

(equipment

manufactured on

and after October 6, 2026)

(%)

Maximum standby loss

(equipment manufactured on

and after October 29, 2003)

b

Maximum standby loss

(equipment manufactured on

and after October 6, 2026)

b

Electric storage water heaters

All

N/A

N/A

0.30 + 27/V

m

(%/h)

0.30 + 27/V

m

(%/h)

Gas-fired storage water heaters and storage-type instantaneous water heaters

All

80

95

Q/800 + 110(V

r

)

1/2

(Btu/h)

0.86 × [Q/800 + 110(V

r

)

1/2

] (Btu/h)

Oil-fired storage water heaters

All

80

80

Q/800 + 110(V

r

)

1/2

(Btu/h)

Q/800 + 110(V

r

)

1/2

(Btu/h)

Electric instantaneous water heaters

c

<10 gal

≥10 gal

80

77

80

77

N/A

2.30 + 67/V

m

(%/h)

N/A

2.30 + 67/V

m

(%/h)

Gas-fired instantaneous water heaters and hot water supply boilers

<10 gal

≥10 gal

80

80

96

96

N/A

Q/800 + 110(V

r

)

1/2

(Btu/h)

N/A

Q/800 + 110(V

r

)

1/2

(Btu/h)

Oil-fired instantaneous water heater and hot water supply boilers

<10 gal

≥10 gal

80

78

80

78

N/A

Q/800 + 110(V

r

)

1/2

(Btu/h)

N/A

Q/800 + 110(V

r

)

1/2

(Btu/h)

a

V

m

is the measured storage volume, and V

r

is the rated storage volume, both in gallons. Q is the rated input in Btu/h, as determined pursuant to 10 CFR 429.44

0

96

96

N/A

Q/800 + 110(V

r

)

1/2

(Btu/h)

N/A

Q/800 + 110(V

r

)

1/2

(Btu/h)

Oil-fired instantaneous water heater and hot water supply boilers

<10 gal

≥10 gal

80

78

80

78

N/A

Q/800 + 110(V

r

)

1/2

(Btu/h)

N/A

Q/800 + 110(V

r

)

1/2

(Btu/h)

a

V

m

is the measured storage volume, and V

r

is the rated storage volume, both in gallons. Q is the rated input in Btu/h, as determined pursuant to 10 CFR 429.44.

b

Water heaters and hot water supply boilers with a rated storage volume greater than 140 gallons need not meet the standby loss requirement if:

(1) The tank surface area is thermally insulated to R-12.5 or more, with the R-value as defined in § 431.102

(2) A standing pilot light is not used; and

(3) For gas-fired or oil-fired storage water heaters, they have a flue damper or fan-assisted combustion.

c

The compliance date for energy conservation standards for electric instantaneous water heaters is January 1, 1994.

(b) Each unfired hot water storage tank manufactured on and after October 29, 2003, must have a minimum thermal insulation of R-12.5.

(c) Each residential-duty commercial water heater must meet the applicable energy conservation standard level(s) as follows:

Table 2 to § 431.110(

c

)—Residential-Duty Commercial Water Heater Energy Conservation Standards

Equipment

Specifications

a

Draw pattern

Uniform energy factor

b

Equipment manufactured before October 6, 2026

Equipment manufactured after October 6, 2026

Gas-fired storage

>75 kBtu/hr and ≤105 kBtu/hr and ≤120 gal

Very Small

Low

Medium

High

0.2674−(0.0009 × V

r

)

0.5362−(0.0012 × V

r

)

0.6002−(0.0011 × V

r

)

0.6597−(0.0009 × V

r

)

0.5374−(0.0009 × V

r

)

0.8062−(0.0012 × V

r

)

0.8702−(0.0011 × V

r

)

0.9297−(0.0009 × V

r

)

Oil-fired storage

>105 kBtu/hr and ≤140 kBtu/hr and ≤120 gal

Very Small

Low

Medium

High

0.2932−(0.0015 × V

r

)

0.5596−(0.0018 × V

r

)

0.6194−(0.0016 × V

r

)

0.6470−(0.0013 × V

r

)

0.2932−(0.0015 × V

r

)

0.5596−(0.0018 × V

r

)

0.6194−(0.0016 × V

r

)

0.6470−(0.0013 × V

r

)

Electric instantaneous

>12 kW and ≤58.6 kW and ≤2 gal

Very Small

Low

Me

12 × V

r

)

0.8702−(0.0011 × V

r

)

0.9297−(0.0009 × V

r

)

Oil-fired storage

>105 kBtu/hr and ≤140 kBtu/hr and ≤120 gal

Very Small

Low

Medium

High

0.2932−(0.0015 × V

r

)

0.5596−(0.0018 × V

r

)

0.6194−(0.0016 × V

r

)

0.6470−(0.0013 × V

r

)

0.2932−(0.0015 × V

r

)

0.5596−(0.0018 × V

r

)

0.6194−(0.0016 × V

r

)

0.6470−(0.0013 × V

r

)

Electric instantaneous

>12 kW and ≤58.6 kW and ≤2 gal

Very Small

Low

Medium

High

0.80

0.80

0.80

0.80

0.80

0.80

0.80

0.80

a

Additionally, to be classified as a residential-duty commercial water heater, a commercial water heater must meet the following conditions: (1) If the water heater requires electricity, it must use a single-phase external power supply; and (2) The water heater must not be designed to heat water to temperatures greater than 180 °F.

b

V

r

is the rated storage volume (in gallons), as determined pursuant to 10 CFR 429.44.

[88 FR 69822, Oct. 6, 2023]

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.

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