How Much Electricity Does a Space Heater Use?
So how much electricity does a space heater use? Most portable space heaters are capped near 1,500 watts by design, with smaller units running as low as 400 watts. Because they're one of the highest-wattage things you're likely to plug into a wall outlet, even a few hours a day adds up fast — use the calculator below with your own rate to see the real cost.
Calculate your cost to run a space heater
Enter your rate to see your estimate.
What affects how much electricity a space heater uses
Wattage is the biggest factor, and most consumer units are capped around 1,500 W regardless of brand since that's close to the limit of a standard 15-amp household circuit. Beyond that, how long it runs matters more than almost any other factor here: a thermostat or timer that cycles the heater off once a room reaches temperature can cut total runtime substantially compared to one left running continuously. Room size and insulation also affect how long the heater has to run to keep a space comfortable.
How to reduce your space heater's electricity use
- Use a model with a built-in thermostat so it cycles off once the room is warm
- Heat only the room you're in and close doors to keep the warmth contained
- Set a timer or turn it off before leaving the room or going to sleep
- Check for drafts around windows and doors, since heat lost there means more runtime
Typical wattage figure: 400-1,500 W. Source: Office of Congressional Workplace Rights (U.S. government) — Fast Facts: Portable Space Heaters. Most consumer units are capped near 1,500 W by design. We review this figure periodically and update it if the source changes; last checked September 2026.
Frequently asked questions
How many watts does a space heater use?
Most portable space heaters run 400 to 1,500 watts, and the large majority of consumer models are capped at 1,500 watts, close to the safe limit for a standard household circuit, according to the U.S. Office of Congressional Workplace Rights.
How much does it cost to run a space heater?
A 1,500-watt heater run 4 hours a day at the U.S. average rate of about 16.5 cents/kWh costs roughly $3 a day, or around $90 a month if run every day. Use the calculator above with your own heater's wattage and rate for an exact figure.
Is it cheaper to run a space heater or central heat?
It depends on how much of your home you're heating. A space heater can cost less than running central heat throughout an entire house if you're only warming one occupied room, but it usually costs more than central heat once you're trying to warm several rooms at once, since central systems are built for that at a lower cost per square foot.
How can I reduce how much electricity my space heater uses?
Choose a model with a built-in thermostat so it stops drawing power once the room reaches temperature, close the door to keep heat from escaping the room, and turn it off (rather than leaving it running) whenever you leave or go to sleep.
This page provides estimates based on typical wattage figures and the numbers you enter. Actual electricity cost depends on your specific heater model, thermostat settings, and how long it actually runs.