The short answer
A 1,500 W space heater costs about 27 cents an hour, or $65.92 a month at 8 hours a day, at the U.S. average electricity rate of 18.31¢ per kWh (July 2026). Heating a whole 1,800 sq ft house with a gas furnace for the same hours costs about $229.74, so the space heater is the cheaper choice for one room, if you turn the central heat down.
Space heater vs gas furnace in every state
A 1,500 W heater in a 150 sq ft room vs heating a 1,800 sq ft house, 8 hours a day for 30 days, at each state's electricity rate (July 2026) and gas price (2025).
| Alabama | $59.04 | $262.99 | $283.39 | 16.40¢ |
|---|---|---|---|---|
| Alaska | $103.79 | $194.10 | $498.18 | 28.83¢ |
| Arizona | $55.37 | $278.26 | $265.77 | 15.38¢ |
| Arkansas | $51.59 | $288.30 | $247.62 | 14.33¢ |
| California | $121.00 | $329.63 | $580.78 | 33.61¢ |
| Colorado | $61.20 | $167.29 | $293.76 | 17.00¢ |
| Connecticut | $86.98 | $252.05 | $417.48 | 24.16¢ |
| Delaware | $66.53 | $239.17 | $319.33 | 18.48¢ |
| District of Columbia | $90.76 | $249.81 | $435.63 | 25.21¢ |
| Florida | $54.11 | $381.60 | $259.72 | 15.03¢ |
| Georgia | $58.57 | $305.82 | $281.15 | 16.27¢ |
| Hawaii | $172.80 | $784.47 | $829.44 | 48.00¢ |
| Idaho | $49.43 | $115.17 | $237.25 | 13.73¢ |
| Illinois | $69.19 | $168.49 | $332.12 | 19.22¢ |
| Indiana | $60.23 | $172.08 | $289.09 | 16.73¢ |
| Iowa | $57.56 | $158.90 | $276.31 | 15.99¢ |
| Kansas | $54.97 | $221.80 | $263.87 | 15.27¢ |
| Kentucky | $49.72 | $213.12 | $238.64 | 13.81¢ |
| Louisiana | $45.79 | $260.44 | $219.80 | 12.72¢ |
| Maine | $116.68 | $283.80 | $560.04 | 32.41¢ |
| Maryland | $77.08 | $241.72 | $369.96 | 21.41¢ |
| Massachusetts | $109.76 | $375.31 | $526.87 | 30.49¢ |
| Michigan | $82.98 | $163.54 | $398.30 | 23.05¢ |
| Minnesota | $62.82 | $164.44 | $301.54 | 17.45¢ |
| Mississippi | $52.34 | $249.36 | $251.25 | 14.54¢ |
| Missouri | $57.92 | $223.75 | $278.04 | 16.09¢ |
| Montana | $53.96 | $134.64 | $259.03 | 14.99¢ |
| Nebraska | $49.61 | $170.73 | $238.12 | 13.78¢ |
| Nevada | $45.97 | $196.79 | $220.67 | 12.77¢ |
| New Hampshire | $95.76 | $278.71 | $459.65 | 26.60¢ |
| New Jersey | $90.68 | $212.82 | $435.28 | 25.19¢ |
| New Mexico | $57.92 | $147.22 | $278.04 | 16.09¢ |
| New York | $107.64 | $263.29 | $516.67 | 29.90¢ |
| North Carolina | $54.58 | $245.91 | $261.96 | 15.16¢ |
| North Dakota | $48.28 | $142.28 | $231.72 | 13.41¢ |
| Ohio | $70.02 | $207.42 | $336.10 | 19.45¢ |
| Oklahoma | $51.66 | $215.36 | $247.97 | 14.35¢ |
| Oregon | $57.49 | $250.26 | $275.96 | 15.97¢ |
| Pennsylvania | $78.19 | $225.25 | $375.32 | 21.72¢ |
| Rhode Island | $101.84 | $324.39 | $488.85 | 28.29¢ |
| South Carolina | $55.69 | $253.25 | $267.32 | 15.47¢ |
| South Dakota | $55.33 | $147.67 | $265.59 | 15.37¢ |
| Tennessee | $49.36 | $177.32 | $236.91 | 13.71¢ |
| Texas | $57.17 | $290.84 | $274.41 | 15.88¢ |
| Utah | $47.23 | $152.61 | $226.71 | 13.12¢ |
| Vermont | $85.50 | $269.58 | $410.40 | 23.75¢ |
| Virginia | $63.18 | $251.45 | $303.26 | 17.55¢ |
| Washington | $52.96 | $263.89 | $254.19 | 14.71¢ |
| West Virginia | $56.81 | $206.68 | $272.68 | 15.78¢ |
| Wisconsin | $68.62 | $160.85 | $329.36 | 19.06¢ |
| Wyoming | $51.70 | $175.82 | $248.14 | 14.36¢ |
Monthly costs. Gas prices are each state's 2025 average residential price (a few states use the year before).
How it works
The formula
house BTU = heater BTU × house ÷ room
gas $ = house BTU ÷ AFUE ÷ 1,036,000 × $ per Mcf
heat pump $ = house BTU ÷ 3,412 ÷ COP × rate
Assumptions
- Keeping the whole house as warm as the heated room takes about the same heat per square foot. Real houses vary: an open plan, poor insulation or big windows change the numbers.
- The space heater runs at full power for the hours you enter. With a thermostat it cycles off, so real cost is often lower.
- Natural gas carries about 1,036 BTU per cubic foot (EIA). Gas prices are annual averages, because monthly prices swing with fixed charges spread over little summer use.
- A heat pump's COP falls in very cold weather. 2.5 is a fair seasonal average for a modern unit; cold-climate models do better.
Worked example: one room vs the whole house
1,500 W heater, 150 sq ft room, 1,800 sq ft house, 8 hours a day
- Space heater: 1.5 kWh × $0.1831 = $0.27 an hour, × 240 hours = $65.92 a month
- Heat the house needs: 5,118 BTU × 12 = 61,416 BTU an hour
- Gas furnace: 61,416 ÷ 0.95 ÷ 1,036,000 × $15.34 = $0.96 an hour = $229.74 a month
- Heat pump: 7.2 kWh an hour × 240 hours = 1,728 kWh × $0.1831 = $316.40 a month
Ways to cut the cost
- Turn the central heat down. A space heater only saves money if the thermostat for the rest of the house goes down a few degrees.
- Close the door. A heater in a closed room keeps the heat where you are.
- Use the thermostat and low setting. 750 W on low costs half as much per hour, and a thermostat cycles the heater off once the room is warm.
- Heat people, not air. A heated blanket (about 100 W) or a heated mattress pad costs a fraction of a space heater overnight.
- Plug it straight into the wall. Not an extension cord, and not on the same circuit as other big loads.
Questions people ask
Is it cheaper to use a space heater or central heat?
For one room, usually yes, if you turn the central heat down. A 1,500 W space heater costs about 27 cents an hour at the U.S. average electricity rate (18.31¢ per kWh, EIA July 2026). Heating a whole 1,800 sq ft house to the same comfort with a 95% gas furnace costs about 96 cents an hour at the 2025 average gas price. But a space heater costs more per unit of heat than gas or a heat pump, so heating the whole house with space heaters is the most expensive option.
How much does it cost to run a space heater for 8 hours?
A 1,500 W heater uses 12 kWh in 8 hours, about $2.20 at the U.S. average rate, or $65.92 a month if you use it every day.
Does a space heater use a lot of electricity?
Yes. At 1,500 watts, a space heater is one of the biggest loads in a home, about the same as a hair dryer, but it runs for hours instead of minutes. Eight hours a day uses about 360 kWh a month, close to half of an average home's usage.
Which is cheaper, a heat pump or a gas furnace?
It depends on your state's prices. At the U.S. averages a heat pump with a COP of 2.5 costs about $1.32 an hour to heat the example house and a 95% gas furnace about 96 cents. Where electricity is cheap or gas expensive, the heat pump wins. Use the state picker to see your state.
Are oil-filled radiators cheaper than other space heaters?
No. Every electric resistance heater turns 1 watt of electricity into the same heat, so a 1,500 W radiator, ceramic or infrared heater costs the same per hour on full power. Radiators feel gentler and keep warm after switching off, and a thermostat that cycles the heater saves the most.