Heat pump vs. furnace: how they work and how they compare

Heat pumps and furnaces heat a home in different ways, and they are rated with different efficiency measures. This guide explains how each one works and the federal minimums for new equipment. It also covers where DOE's 95% AFUE rule for gas furnaces stands as of October 2026. The later sections cover cold-climate heat pump specs, backup heat and national energy prices from the U.S. Energy Information Administration (EIA). We do not estimate operating costs.

How a heat pump heats a home

ENERGY STAR's air-source heat pump page says, "Electric ASHPs use the difference between outdoor air temperatures and indoor air temperatures to cool and heat your home." ASHP stands for air-source heat pump. The page goes on: "Because heat pumps move heat rather than converting it from fuel, as combustion heating systems do, an ASHP is so efficient that it can deliver up to three times more heat energy to a home than the electrical energy it consumes."

A 2017 DOE Building America Solution Center (BASC) guide explains how this works. Heat pumps use "the same refrigeration cycle technology as your home’s refrigerator or air conditioner, pulling heat from one environment and dumping it into another." Unlike cooling-only air conditioners, heat pumps have a reversing valve. BASC says the valve lets them "reverse the cycle to pull heat from the outdoor air and deliver it indoors in the wintertime." BASC is published by Pacific Northwest National Laboratory for DOE.

How a furnace heats a home

DOE's 2022 Energy Saver Guide says, "Furnaces are the most common way to heat a home in the United States. Central forced-air furnaces distribute heated air through the house via ducts. Most are fueled by natural gas; others use electricity, oil, or propane."

Furnaces are rated by AFUE, or annual fuel utilization efficiency. ENERGY STAR's furnace criteria page describes AFUE as, "In general, the percentage of the heat in the incoming fuel which is converted to space heat instead of being lost." Our furnace guide covers AFUE, ENERGY STAR furnace criteria and carbon monoxide safety in more depth.

Federal efficiency minimums for heat pumps and furnaces

Under 10 CFR 430.32, "Central air conditioners and central air conditioning heat pumps manufactured on or after January 1, 2023, must have a Seasonal Energy Efficiency Ratio 2 and a Heating Seasonal Performance Factor 2 not less than" the levels in its table. For split-system heat pumps, the table lists 14.3 SEER2 and 7.5 HSPF2. This guide covers only the split-system row.

For furnaces, the same section sets 80.0% AFUE for non-weatherized gas furnaces. This level covers furnaces made on or after November 19, 2015, but before December 18, 2028. That class does not include mobile home furnaces.

Where the 95% AFUE furnace rule stands

The eCFR, current as of October 1, 2026, still lists a higher level for later gas furnaces. It says the AFUE for non-weatherized gas furnaces and mobile home gas furnaces "manufactured on and after December 18, 2028" shall not be less than 95.0%. That level comes from DOE's December 18, 2023 final rule. In an April 27, 2026 notice, DOE said the 95% levels "effectively require the use of condensing technology."

Date	Event
December 18, 2023	DOE publishes the final rule; compliance "is required on and after December 18, 2028"
February 19, 2026	DOE receives a petition from the American Gas Association, the American Public Gas Association and the National Propane Gas Association to amend the compliance dates
April 27, 2026	DOE publishes a notice of the petition
June 8, 2026	The Supreme Court grants the petition in No. 25-879, vacates the D.C. Circuit's judgment and remands the case to the D.C. Circuit
October 1, 2026	The eCFR, current as of this date, still lists the 95.0% level

The Supreme Court docket entry reads, "Judgment VACATED and case REMANDED for further consideration in light of the position asserted by the Solicitor General in his brief for the United States filed on April 28, 2026." We did not review that brief, and we did not check what has happened in the case since the remand. As of October 2026, we found no DOE action in the Federal Register that grants the petition or changes the 2028 date.

HSPF2 and COP: two ways to rate heat pump heating

ENERGY STAR's heat pump criteria page defines both terms. "HSPF2 is the total space heating required in region IV during the space heating season, expressed in Btu, divided by the total electrical energy consumed by the heat pump system during the same season, expressed in watt-hours." HSPF2 is a seasonal rating.

COP is measured differently. ENERGY STAR says, "COP means the ratio of the average rate of space heating delivered to the average rate of electrical energy consumed by the heat pump." Those rates "must be determined from a single test or, if derived via interpolation, must be determined at a single set of operating conditions."

The Northeast Energy Efficiency Partnerships (NEEP) gives background for its cold-climate specification. Its page refers to HSPF, not HSPF2. It says the HSPF metric "does not include low temperature testing points below 17°F, assumes the use of electric resistance elements, and tests in steady-state operation (as opposed to allowing modulation)."

Heat pumps in cold climates

A 2024 BASC guide says, "Until recently, natural gas, fuel oil, and other combustion heating systems have been preferred over heat pumps in cold climates because they do not lose heating capacity when the outside temperature drops."

NEEP's specification "was designed to identify air source heat pumps that are best suited to heat efficiently in cold climates (IECC climate zone 4 and higher)." Its Version 4.0, effective January 1, 2023, requires a "COP at 5°F ≥ 1.75 at maximum capacity operation."

ENERGY STAR lists its Version 6.2 specification, "Rev. February 2, 2026," as current. For its Cold Climate designation, Table 2 sets at least 15.2 SEER2 and 8.5 HSPF2 for non-ducted split heat pumps. The levels for ducted splits are at least 15.2 SEER2 and 8.1 HSPF2.

Backup heat for heat pumps

The 2017 BASC guide says, "Because the heating efficiency of standard, central air-source heat pumps drops when outside temperatures drop below about 35°F, a backup heat source is often needed." All-electric heat pumps "come equipped with electric resistance strip heaters for supplementary heat if needed." Dual-fuel systems pair the heat pump "with another source of supplementary heat, such as a gas furnace."

For cold-climate models, ENERGY STAR says, "Your cold climate ASHP will continue working at temperatures below 5°F, but pairing it with a back-up energy source will heat your home the most efficiently when temperatures are even lower." DOE's 2022 guide adds this thermostat advice: "Do not set back the heat pump’s thermostat manually if it causes backup electric-resistance heating to come on. This type of heating is more expensive."

National electricity and natural gas prices (EIA)

EIA released its Electric Power Monthly on September 24, 2026. It puts the U.S. average residential electricity price at 18.19 cents per kilowatthour for January through July 2026. This figure is a preliminary estimate. The figure for the same months of 2025 was 17.01 cents. EIA's annual natural gas series shows a 2025 U.S. residential average of $15.34 per thousand cubic feet. The monthly series shows $14.95 for February 2026 and $16.16 for March 2026.

These are national averages in different units. We do not convert them or estimate heating bills. To work with your own rates, use our heat pump vs. furnace calculator. For regional detail, see our guides to choosing a heat pump or gas furnace in western Washington and a heat pump or gas furnace in Ohio. If you heat with oil, see our guide to switching from oil to a heat pump.