How much does it cost to run a space heater?
Short answer: A 1,500 W space heater on high uses 1.5 kWh an hour. At the U.S. average residential price of 18.19¢/kWh (January–July 2026, EIA), that is about $0.27 an hour, or about $49.11 a month at 6 hours a day. In Hawaii the same month costs over $120; in North Dakota, about $33.
The formula
Every electric resistance heater turns 100% of the electricity it uses into heat, so a "1,500 W" heater uses 1.5 kWh for every hour it runs at full power. Cost = kW × hours × price per kWh. Labels like "energy-saving" or "infrared" don't change that: a 1,500 W heater of any type delivers the same 5,118 BTU an hour for the same money. What saves money is heating one room instead of the whole house, or running the heater on its low setting or its thermostat.
Monthly cost by hours of use
At the U.S. average of 18.19¢/kWh, 30 days a month:
| Heater setting | 2 h/day | 4 h/day | 8 h/day |
|---|---|---|---|
| 750 W (low) | $8.19 | $16.37 | $32.74 |
| 1,500 W (high) | $16.37 | $32.74 | $65.48 |
With its thermostat on, a heater in a closed, insulated room cycles off part of the time, so the real figure is often 30–60% lower than the full-power number. A plug-in energy meter (about $20) tells you exactly what yours uses.
What it costs in the cheapest and most expensive states
1,500 W, 6 hours a day for 30 days, at each state's average residential price from the EIA (January–July 2026):
| State | ¢/kWh | Per hour | Per month |
|---|---|---|---|
| North Dakota | 12.36 | $0.19 | $33.37 |
| Nebraska | 12.90 | $0.19 | $34.83 |
| Idaho | 12.96 | $0.19 | $34.99 |
| Utah | 13.16 | $0.20 | $35.53 |
| Louisiana | 13.35 | $0.20 | $36.05 |
| New York | 29.38 | $0.44 | $79.33 |
| Maine | 29.99 | $0.45 | $80.97 |
| Massachusetts | 30.14 | $0.45 | $81.38 |
| California | 33.25 | $0.50 | $89.78 |
| Hawaii | 46.28 | $0.69 | $124.96 |
Every state has its own page with this calculation: electricity prices by state.
Space heater or furnace?
Heating one room with a space heater can cost less than heating the whole house with the furnace, as long as you turn the central thermostat down. Heating the whole house with space heaters almost never does: a heat pump delivers 2–4 kWh of heat for every kWh it uses, a space heater exactly one.
Safety. Plug space heaters straight into a wall outlet, never an extension cord or power strip: 12.5 A for hours heats undersized cords and loose plugs. Keep 3 feet of clearance from anything that can burn.