Is it cheaper to …? Heating and cooling questions, answered with numbers

By Karsten Looks

The short answers, then the numbers behind them. Prices: 2025 average residential electricity price per state (EIA-861), natural gas 2025 (EIA), heating oil and propane for the 2025/26 heating season (EIA).

Is it cheaper to heat with gas or electricity?

With baseboards, an electric furnace or space heaters: gas is cheaper in 51 of 51 states (including DC). At U.S. average prices, a million BTU of heat costs $50 from electric resistance and $16 from a 92% gas furnace. With a heat pump the picture changes: it delivers several kWh of heat per kWh of electricity, and it is the cheapest option in 16 states in the table below, gas in 34.

Cost of one million BTU of heat delivered into the home. * No state survey for this fuel: U.S. average price. Gas and propane furnace 92% efficient, oil 84%, electric resistance 100%, heat pump: high-efficiency model with its seasonal COP at a typical weather station in each state (same method as the heat pump vs furnace calculator, which also uses your ZIP code). Cheapest option in bold.

Is it cheaper to use space heaters or central heat?

Only for one or two rooms, with the rest of the house turned down. A space heater is electric resistance heat, the most expensive column in the table above in most states. A 1,500-watt heater costs $0.26 an hour at the U.S. average price and makes about 5,100 BTU of heat an hour; a central system has to heat the whole house. If you sit in one room for the evening and the thermostat for the rest of the home is turned down, the heater can win; heating the whole home with several heaters almost never does. Space heater cost in your state.

Is it cheaper to run a fan or the air conditioner?

A fan, by far, but it does not cool the room. A ceiling or box fan draws tens of watts; a window AC unit about 1,000 watts and a 3-ton central system about 3,500 watts (typical values used in our bill calculator). At 17.2¢ per kWh that is roughly $0.009 an hour for a 50-watt fan against $0.17 for the window unit and $0.60 for central air. A fan only saves money if it lets you set the thermostat higher; a fan running in an empty room just adds cost. In U.S. homes with ceiling fans, all fans together used 226 kWh a year (EIA RECS 2020).

Is it cheaper to leave the AC on all day?

No. A home gains heat from outside in proportion to the difference between inside and outside temperature, so a warmer house while you are away gains less heat, and the AC has less to remove in total, even if it runs hard when you come back. The U.S. Department of Energy estimates that setting the thermostat back 7–10 °F for 8 hours a day can save up to 10% a year on heating and cooling (Energy Saver). The same logic applies to heat in winter. Exceptions: some heat pumps switch to expensive backup heat after a large setback in cold weather, and on time-of-use rates a pre-cooled house before the expensive afternoon hours can cost less.

Is it cheaper to run appliances at night?

Only on a time-of-use rate. On a standard flat rate a kWh costs the same at 2 a.m. as at 5 p.m. On a time-of-use or EV rate, evening peak hours cost more and night hours less; your utility's rate page lists the hours. Look up your utility's average price on your state's page.

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