Short answer: a typical 1,500-watt space heater uses 1.5 kWh per hour on high. At the average US residential price of about 18.2 cents per kWh forecast for 2026 by the EIA, that’s about 27 cents an hour, or roughly $66 a month if it runs 8 hours a day. It only saves money if you turn the main heat down while you use it.
The formula
Cost per hour = heater watts ÷ 1,000 × your price per kWh.
Find your price per kWh on your bill (total charges ÷ total kWh). Most space heaters list their wattage on the label: 1,500 W on high and around 750 W on low is the most common setup.
Real costs at different rates
| Setting | Per hour at 14¢/kWh | Per hour at 18.2¢/kWh | Per hour at 30¢/kWh | Month, 8 h/day at 18.2¢ |
|---|---|---|---|---|
| Low (750 W) | 10.5¢ | 13.7¢ | 22.5¢ | about $33 |
| High (1,500 W) | 21¢ | 27.3¢ | 45¢ | about $66 |
Thermostat-controlled heaters cycle on and off once the room is warm, so real use is often lower than these full-power numbers.
When a space heater saves money
Every electric heater turns 100% of its electricity into heat, so no model is “more efficient” than another at the plug, whatever the marketing says. What saves money is heating less space:
- You turn the central thermostat down and heat only the room you’re in. The DOE says heating only occupied zones can save more than 20% compared with heating the whole house (energy.gov).
- Your home heats with expensive electric resistance, oil or propane, and you spend most evenings in one room.
When it costs you more
- You run it on top of normal whole-house heating.
- You have a heat pump. A heat pump can deliver up to three times more heat per kWh than a space heater (energy.gov), so leaning on the heat pump is usually cheaper.
- You heat a drafty room. Fix the drafts first; see 12 ways to cut your winter bill.
Safety first
Heating equipment caused 13% of U.S. home fires and 18% of home fire deaths in 2016-2020, and space heaters were behind about a third of those fires and most of the deaths, according to NFPA data summarized by the Office of Congressional Workplace Rights.
- Buy a model with tip-over and overheat shutoff and a safety lab certification label (UL, ETL or CSA).
- Plug it straight into a wall outlet, never an extension cord or power strip.
- Keep it at least 3 feet from curtains, bedding, paper and furniture.
- Turn it off when you leave the room or go to sleep.
- Keep it away from water, children and pets.
FAQ
Are oil-filled radiators cheaper to run? Not per hour at the same wattage. They hold heat longer and feel gentler, but 1,500 W costs the same either way.
Is a ceramic or infrared heater cheaper? No, same rule: watts determine cost. Infrared heaters warm people and objects directly, which can feel warmer at a lower setting.
Can I run two on one circuit? Two 1,500 W heaters on one 15-amp circuit can trip the breaker. Use separate circuits.