§ 431.110 - Energy conservation standards and their effective dates.

§ 431.110 Energy conservation standards and their effective dates.

Cross Reference

Link to an amendment published at 88 FR 69822, Oct. 6, 2023.

(a) Each commercial storage water heater, instantaneous water heater, unfired hot water storage tank 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 in 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.

Equipment category

Table 1 to § 431.110(a)—Commercial Water Heater Energy Conservation Standards

standard^a Maximum standby loss^c 80 8080 80 80 7880 78

Equipment	Size	Energy conservation				standardsa
		Minimum thermal efficiency (equipment manufactured on and after October 299, 20032015) b (%)	Minimum thermal efficiency (equipment manufactured on and after October 29, 2003 and before October 9, 2015)b 6, 2026) (%) Minimum thermal efficiency	Maximum standby loss (equipment manufactured on and after October 929, 20152003)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/Vm (%/hr)	N/A	N/A	h)	0.30 + 27/Vm (%/h)
Gas-fired storage water heaters	≤155,000 Btu/hr	and storage-type instantaneous water heaters	All	80	95	Q/800 + 110(Vr)1⁄/2 (Btu/hr)	80	80	>155,000 Btu/hr	h)	0.86 × [Q/800 + 110(Vr)1⁄/2] (Btu/hrh)	80	80
Oil-fired storage water heaters	≤155,000 Btu/hr	All	80	80	Q/800 + 110(Vr)1⁄/2 (Btu/hr)	78	80	>155,000 Btu/hr	h)	Q/800 + 110(Vr)1⁄/2 (Btu/hr)	78	80	h)
Electric instantaneous water heatersc	<10 gal ≥10 gal	80 77	80 77	N/A 2.30 + 67/Vm (%/h)	N/A 2.30 + 67/Vm (%/h)
Gas-fired instantaneous water heaters and hot water supply boilers	<10 gal ≥10 gal	80 80	96 96	N/A Q/800 + 110(Vr)1⁄/2 (Btu/hr)	h)	N/A Q/800 + 110(Vr)1/2 (Btu/h)
Oil-fired instantaneous water heaters heater and hot water supply boilers	<10 gal ≥10 gal	80 78	80 78	N/A Q/800 + 110(Vr)1⁄/2 (Btu/hr)	Equipment category		Size	Minimum thermal insulation
Unfired hot water storage tank		All	R–12.5
h)	N/A Q/800 + 110(Vr)1/2 (Btu/h)

^a V_m is the measured storage volume (in gallons), and V_r is the rated storage volume (, both in gallons). Q is the nameplate rated input rate in Btu/hr.

^b For hot water supply boilers with a capacity of less than 10 gallons: (1) The standards are mandatory for products manufactured on and after October 21, 2005, and (2) products manufactured prior to that date, and on or after October 23, 2003, must meet either the standards listed in this table or the applicable standards in subpart E of this part for a “commercial packaged boiler.”

^c h, as determined pursuant to 10 CFR 429.44.

^b Water heaters and hot water supply boilers having more with a rated storage volume greater than 140 gallons of storage capacity 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 A standing pilot light is not used; and

(3) for For gas-fired or oil-fired storage water heaters, they have a fire 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:

Product class

Table 2 to § 431.110(c)—Residential-Duty Commercial Water Heater Energy Conservation Standards

Equipment	Specificationsa	Draw pattern	Uniform energy factorb
			Equipment manufactured before October 6, 2026	Equipment manufactured after October 6, 2026
Gas-fired Storagestorage	>75 kBtu/hr and ≤105 kBtu/hr and ≤120 gal	Very Small Low Medium High	0.2674 − 2674−(0.0009 × Vr) 0.5362 − 5362−(0.0012 × Vr)	Medium	0.6002 − 6002−(0.0011 × Vr)	High	0.6597 − 6597−(0.0009 × Vr)	0.5374−(0.0009 × Vr) 0.8062−(0.0012 × Vr) 0.8702−(0.0011 × Vr) 0.9297−(0.0009 × Vr)
Oil-fired Storagestorage	>105 kBtu/hr and ≤140 kBtu/hr and ≤120 gal	Very Small Low Medium High	0.2932 − 2932−(0.0015 × Vr) 0.5596 − 5596−(0.0018 × Vr)	Medium	0.6194 − 6194−(0.0016 × Vr)	High	0.6740 − 6470−(0.0013 × Vr)	Electric Instantaneous	0.2932−(0.0015 × Vr) 0.5596−(0.0018 × Vr) 0.6194−(0.0016 × Vr) 0.6470−(0.0013 × Vr)
Electric instantaneous	>12 kW and ≤58.6 kW and ≤2 gal	Very Small Low Medium High	0.80	Low	0.80	Medium	0.80	High	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 If the water heater requires electricity, it must use a single-phase external power supply; and (2) the 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.

[81 88 FR 9623869822, DecOct. 296, 20162023]