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How Many Watts Does a Space Heater Use? Amps, Cost, and What Will Run One
Most electric space heaters use 1,500 watts on high and about 750 watts on low. At 1,500 watts a heater pulls 12.5 amps and uses 1.5 kWh every hour it runs. That is a lot of power for a battery, but easy work for a generator.
Here is what a space heater costs to run, and what it takes to keep one going during a winter power outage.
Space heater watts and amps by setting
| Setting | Watts | Amps at 120V | kWh per hour |
|---|---|---|---|
| High (most heaters) | 1,500 W | 12.5 A | 1.5 kWh |
| Low | 750 W | 6.25 A | 0.75 kWh |
Amps = watts / 120. Check the label on your heater; small personal heaters use less, and some low settings are 600 or 900 watts.
Why 1,500 watts? A standard household outlet is on a 15 amp, 120 volt circuit. At 12.5 amps, a 1,500 W heater uses most of that circuit by itself, which is why heaters trip breakers when something else is plugged in on the same circuit.
How much does it cost to run a space heater?
Multiply kWh by your electric rate. At 17 cents per kWh (use the rate on your own bill):
- 1 hour on high: 1.5 kWh x $0.17 = about $0.26
- 8 hours on high: 12 kWh x $0.17 = about $2.04
- 8 hours on low: 6 kWh x $0.17 = about $1.02
Can a portable power station run a space heater?
Yes, if its output is at least 1,500 watts, but not for long. Heat takes a lot of energy. Use battery Wh x 0.9 / heater watts = hours.
| Power station | Capacity / output | Hours on high (1,500 W) | Hours on low (750 W) | Price |
|---|---|---|---|---|
| Jackery Explorer 1000 v2 | 1,070 Wh / 1,500 W | About 0.6 (at its output limit) | About 1.3 | From $499 |
| Jackery Explorer 2000 v2 | 2,042 Wh / 2,200 W | About 1.2 | About 2.5 | From $899 |
| Jackery HomePower 3000 | 3,072 Wh / 3,600 W | About 1.8 | About 3.7 | From $1,349 |
Capacity and output are from each product page. For an outage, a power station is better spent on the fridge, lights, a furnace blower, and phones. See portable power stations.
Can a generator run a space heater?
Yes, easily. A space heater is a simple resistive load with no startup surge, so any generator with at least 2,000 running watts handles a 1,500 W heater.
- The DuroMax XP5500HX ($629) makes 4,500 running watts on gas. That runs a 1,500 W heater plus a fridge and lights. DuroMax rates it at 9 hours at 50% load and 19 hours at 25% load on gas, and a 1,500 W heater is about a third of its output.
- More in our portable generators collection.
Heating your whole house? A gas furnace heats every room for about the same electricity as one space heater. See How Many Watts Does a Furnace Use?
Need help sizing? Call 1-888-855-7286. Tell us what you need to keep running in an outage and we will match you to the right setup.
Space heater safety during an outage
- Keep the heater at least 3 feet from anything that can burn.
- Plug the heater straight into the wall, generator, or power station. Avoid power strips. If you must use an extension cord from a generator, use a heavy-duty outdoor cord rated for the load.
- Run generators outside only, at least 20 feet from the house, with the exhaust pointed away from doors and windows.
- Turn the heater off when you leave the room or go to sleep.
Space heater wattage FAQ
How many watts does a space heater use? Most use 1,500 watts on high and 750 watts on low.
How many amps does a space heater use? About 12.5 amps on high (1,500 W / 120 V) and about 6.25 amps on low.
Will a 2,000 watt generator run a space heater? Yes, a 2,000 watt generator can run one 1,500 W heater, with little left over.
How long will a power station run a space heater? About 1 to 2 hours on high for a 2,000 to 3,000 Wh power station. Run it on low to roughly double that.
Do space heaters use a lot of electricity? Yes. At 1.5 kWh per hour, an 8-hour day on high uses 12 kWh, or about $2 at 17 cents per kWh.