Guide
Heat pump or gas furnace: where running costs cross, and what moves it
The crossover temperature under nine combinations of electricity and gas prices, and the seasonal swing in the gas price behind it.
Reviewed by TheCostDesk on : the working features and the sources were checked by hand, and the wording read for tone. What a review involves.
Data last checked . Figures are the US average; the calculator adjusts them for a state.
Where the costs cross, under nine price combinations
The outdoor temperature above which a heat pump costs less to run than a 95%-efficient gas furnace, for the same heat delivered.
| Gas price per therm | Electricity at 11 cents per kWh | Electricity at 18.2 cents per kWh | Electricity at 28 cents per kWh |
|---|---|---|---|
| $1.20 ($12.43 per thousand cubic feet) | 18 °F | Gas costs less at every temperature up to 47 °F | Gas costs less at every temperature up to 47 °F |
| $1.56 ($16.16 per thousand cubic feet) | 8 °F | 34 °F | Gas costs less at every temperature up to 47 °F |
| $2.20 ($22.79 per thousand cubic feet) | -2 °F | 14 °F | 41 °F |
Heat pump efficiency (COP) is taken as 3.8 at 47 °F, 2.5 at 17 °F and 1.8 at 5 °F, an illustrative cold-climate model. Your unit's ratings change every cell, and the calculator takes them.
What moves the crossover
Three things.
The price ratio. One therm of gas is 100,000 Btu and one kilowatt-hour is 3,412 Btu, so a million Btu of heat from gas costs the gas price times 10 (therms) divided by the furnace's efficiency, and from a heat pump the electricity price in dollars times about 293 (kilowatt-hours) divided by its COP. At the middle prices above, gas costs $16.42 per million Btu of heat. The pump costs less when its COP is above about 3.25.
Efficiency falls with the cold. A heat pump delivers less heat per unit of electricity as it gets colder, so the crossover is a temperature, not a single yes or no. At the middle prices it is about 34 °F.
The furnace. An older 80% furnace costs about 19% more to run per unit of heat than a 95% one, which moves the crossover colder.
Prices move with the season
The same fuel costs different amounts over a year.
The Energy Information Administration's US residential natural gas price was $16.16 per thousand cubic feet (about $1.56 per therm) in March 2026 and $27.05 (about $2.61 per therm) in August 2026, at 10.36 therms per thousand cubic feet, and the average residential electricity price was 18.16 cents a kilowatt-hour in August 2026 against 17.57 a year earlier. The gas figure is higher in summer partly because fixed monthly charges are spread over little use, so one month's price says little about a heating season. Local rates, tiered or time-of-use electricity pricing and fuel markets all move the inputs, and with them the crossover. A price taken at one moment is one point on that range.
What this leaves out
The comparison is only about running cost per unit of heat.
- Equipment and installation. The up-front cost of each system. See the air conditioner and heat pump cost page for the heat pump side.
- Capacity. Many heat pumps lose capacity in deep cold, and some homes use backup heat there. The crossover only says which fuel costs less per unit of heat at that temperature.
- Defrost, cycling and duct losses are not modelled, nor is a heat pump's cooling in summer.
- Airflow and ducts. A heat pump and a furnace move air differently, and existing ductwork can limit the airflow a heat pump needs, which can lower its real efficiency. The table assumes the rated efficiency.
- Hours at each temperature. A crossover at 34 °F matters differently in a climate that is rarely colder than that and one that is often far colder.
Work it out for your own job
The figures above are examples. These take your numbers.
Sources
Where each figure comes from, and when we last looked.
- Checked sourceU.S. Energy Information Administration, Natural Gas Monthly, average price of natural gas delivered to residential consumers, March 2026 ($16.16 per thousand cubic feet) and August 2026 ($27.05). Data year 2026, checked 2026-11-05.
- Checked sourceU.S. Energy Information Administration, Electric Power Monthly, table 5.6.A, average residential price, August 2026: 18.16 cents per kWh (preliminary; 17.57 in August 2025). Data year 2026, checked 2026-11-05.
- Checked sourceU.S. Energy Information Administration, average heat content of natural gas delivered to consumers: 1,036 Btu per cubic foot in 2025. Data year 2025, checked 2026-11-05.
- Published, secondhandNEEP, Cold Climate Air-Source Heat Pump Specification: manufacturers report COP at 47, 17 and 5 °F; qualifying units exceed a COP of 1.75 at 5 °F. Data year 2022, checked 2026-11-05.
- Our estimateIn this guide: The heat pump efficiency values used (COP 3.8 at 47 °F, 2.5 at 17 °F, 1.8 at 5 °F) are illustrative for a cold-climate model, not any one product, and the straight lines between them are our simplification. Below 5 °F the COP continues down the 5 to 17 °F line. Data year 2026, checked 2026-11-05.
For information only: not advice, a recommendation or a quote. We take care, but our sources can lag and so can we, so a figure may be out of date. Prices change with wages, material costs, the season and local demand; a real quote can fall outside any range.