WAC 51-11C-403325. Table C403.3.2(5) — Minimum efficiency requirements — Warm air furnaces and unit heaters

Table C403.3.2(5) 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 Efficiency d,c Test Procedure a Warm-air furnace, gas fired for application outside the U.S. < 225,000 Btu/h Maximum capacity c 80% AFUE (nonweatherized) or 1% AFUE (weatherized) or 80% E t b,d DOE 10 C.F.R. 430 Appendix N or Section 2.39, Thermal Efficiency, ANSI Z21.47 Warm-air furnace, gas fired < 225,000 Btu/h Maximum capacity c 80% E t b,d before 1/1/2023 81% E t d after 1/1/2023 Section 2.39, Thermal Efficiency, ANSI Z21.47 Warm-air furnace, oil fired < 225,000 Btu/h Maximum capacity c 83% AFUE (nonweatherized) or 78% AFUE (weatherized) or 80% E t b,d DOE 10 C.F.R. 430 Appendix N or Section 42, Combustion UL 727 Warm-air furnace, oil fired < 225,000 Btu/h Maximum capacity c 80% E t before 1/1/2023 82% E t d after 1/1/2023 Section 42, Combustion UL 727 Electric furnaces for applications outside the U.S. < 225,000 Btu/h All 96% AFUE DOE 10 C.F.R. 430 Appendix N Warm air duct furnaces, gas fired All capacities Maximum capacity c 80% E c e Section 2.10, Efficiency, ANSI Z83.8 Warm air unit heaters, gas fired All capacities Maximum capacity c 80% E c e,f Section 2.10, Efficiency, ANSI Z83.8 Warm air unit heaters, oil fired All capacities Maximum capacity c 80% E c e,f Section 40, Combustion, UL 731 Equipment Type Size Category (Input) Subcategory or Rating Condition Minimum Efficiency d,c Test Procedure a Warm-air furnace, gas fired for application outside the U.S. < 225,000 Btu/h Maximum capacity c 80% AFUE (nonweatherized) or 1% AFUE (weatherized) or 80% E t b,d DOE 10 C.F.R. 430 Appendix N or Section 2.39, Thermal Efficiency, ANSI Z21.47 Warm-air furnace, gas fired < 225,000 Btu/h Maximum capacity c 80% E t b,d before 1/1/2023 81% E t d after 1/1/2023 Section 2.39, Thermal Efficiency, ANSI Z21.47 Warm-air furnace, oil fired < 225,000 Btu/h Maximum capacity c 83% AFUE (nonweatherized) or 78% AFUE (weatherized) or 80% E t b,d DOE 10 C.F.R. 430 Appendix N or Section 42, Combustion UL 727 Warm-air furnace, oil fired < 225,000 Btu/h Maximum capacity c 80% E t before 1/1/2023 82% E t d after 1/1/2023 Section 42, Combustion UL 727 Electric furnaces for applications outside the U.S. < 225,000 Btu/h All 96% AFUE DOE 10 C.F.R. 430 Appendix N Warm air duct furnaces, gas fired All capacities Maximum capacity c 80% E c e Section 2.10, Efficiency, ANSI Z83.8 Warm air unit heaters, gas fired All capacities Maximum capacity c 80% E c e,f Section 2.10, Efficiency, ANSI Z83.8 Warm air unit heaters, oil fired All capacities Maximum capacity c 80% E c e,f Section 40, Combustion, UL 731 For SI: 1 British thermal unit per hour = 0.2931 W. a Chapter 6 contains a complete specification of the referenced standards, which include test procedures, including the referenced year version of the test procedure. b Combination units (i.e., furnaces contained within the same cabinet as an air conditioner) not covered by DOE 10 C.F.R. 430 (i.e., 3-phase power or with cooling capacity greater than or equal to 65,000 Btu/h) may comply with either rating. All other units greater than 225,000 Btu/h sold in the U.S. must meet the AFUE standards for consumer products and testing using U.S. DOE's AFUE test procedure at DOE 10 C.F.R. 430 Subpart B, Appendix N. c Compliance of multiple firing rate units shall be at the maximum firing rate. d E t = Thermal efficiency. Units must also include an interrupted or intermittent ignition device (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. e E c = Combustion efficiency (100% less flue losses). See test procedure for detailed discussion. f Units must also include an interrupted or intermittent ignition device (IID) and have either power venting or an automatic flue damper. g This table is a replica of ASHRAE 90.1 Table 6.8.1-5 Warm-Air Furnaces and Combination Warm-Air Furnaces/Air-Conditioning Units, Warm-Air Duct Furnaces, and Unit Heaters — Minimum Efficiency Requirements.