This section covers furnaces, heat pumps, dual-fuel systems, boilers, heat pump water heaters and switching from oil heat.
Non-weatherized gas furnaces made on or after November 19, 2015 must reach 80.0% AFUE under federal rules, as the furnace guide explains. As of October 1, 2026, the eCFR lists 95.0% AFUE for those made on or after December 18, 2028. In a June 30, 2026 docket notice, DOE wrote that it is "currently reconsidering the energy conservation standards" for residential furnaces.
ENERGY STAR says heat pumps move heat rather than converting it from fuel, and DOE's 2022 Energy Saver Guide says most furnaces are fueled by natural gas, as heat pump vs. furnace explains. Split-system heat pumps made on or after January 1, 2023 need at least 7.5 HSPF2 under federal rules. A dual-fuel system pairs a heat pump with a gas or oil furnace, ENERGY STAR says, but we found no primary source that sets one switchover temperature for every home.
DOE's 2022 Energy Saver Guide calls heat pumps an efficient option for homes with central propane or oil, as the guide to switching from oil to a heat pump explains. EIA estimates that about 4.79 million U.S. households heated mainly with oil in winter 2023–2024. DOE's 2024 rule requires compliance with new standards on and after May 6, 2029, as the heat pump water heater guide explains.
