StacksVerified U.S. regulatory reference

16 CFR Part 305, Appendix G6

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov
TypeRange of annual fuel utilization efficiencies (AFUEs)
LowHigh
Gas Boilers (except steam)—All Capacities84 | 96.4
Gas Boilers (steam)—All Capacities82 | 83.4

[87 FR 61475, Oct. 12, 2022]