PDFWAC 51-11C-403234

Table C403.3.2(4)—Minimum efficiency requirements—Warm air furnaces and unit heaters.

Table 403.3.2(4)
Warm Air Furnaces and Combination Warm Air Furnaces/Air-Conditioning Units, Warm Air Duct Furnaces and Unit Heaters, Minimum Efficiency Requirements
Equipment Type
Size Category (Input)
Subcategory or Rating Condition
Minimum Efficiencyd, e
Test Procedurea
Warm air furnaces, gas fired
< 225,000 Btu/h
80% AFUE or 80% Etc
DOE 10 C.F.R. Part 430 or ANSI Z21.47
 
≥ 225,000 Btu/h
Maximum capacityc
80% Etf
ANSI Z21.47
Warm air furnaces, oil fired
< 225,000 Btu/h
83% AFUE or 80% Etc
DOE 10 C.F.R. Part 430 or UL 727
 
≥ 225,000 Btu/h
Maximum capacityb
81% Etg
UL 727
Warm air duct furnaces, gas fired
All capacities
Maximum capacityb
80% Ec
ANSI Z83.8
Warm air unit heaters, gas fired
All capacities
Maximum capacityb
80% Ec
ANSI Z83.8
Warm air unit heaters, oil fired
All capacities
Maximum capacityb
80% Ec
UL 731
For SI:
1 British thermal unit per hour = 0.2931 W.
a
Chapter 12 of the referenced standard contains a complete specification of the referenced test procedure, including the referenced year version of the test procedure.
b
Minimum and maximum ratings as provided for and allowed by the unit's controls.
c
Combination units not covered by the National Appliance Energy Conservation Act of 1987 (NAECA) (3-phase power or cooling capacity greater than or equal to 65,000 Btu/h [19 kW]) shall comply with either rating.
 
dEt
=
Thermal efficiency. See test procedure for detailed discussion.
 
eEc
=
Combustion efficiency (100% less flue losses). See test procedure for detailed discussion.
 
fEc
=
Combustion efficiency. Units must also include an IID, have jackets not exceeding 0.75 percent of the input rating, and have either power venting or a flue damper. A vent damper is an acceptable alternative to a flue damper for those furnaces where combustion air is drawn from the conditioned space.
 
gEt
=
Thermal efficiency. Units must also include an IID, have jacket losses not exceeding 0.75 percent of the input rating, and have either power venting or a flue damper. A vent damper is an acceptable alternative to a flue damper for those furnaces where combustion air is drawn from the conditioned space.
[Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27A.160 and chapter 19.27 RCW. WSR 19-24-040, § 51-11C-403234, filed 11/26/19, effective 7/1/20. Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-403234, filed 2/1/13, effective 7/1/13.]
Reviser's note: The brackets and enclosed material in the text of the above section occurred in the copy filed by the agency.