How many watts does a space heater use?
Updated
Running watts
1,500 W
Starting watts
1,500 W
Energy per day
9.0 kWh
A space heater typically draws about 1,500 watts while running. At about 6 h of use a day, that is roughly 9.0 kWh per day. These are typical values from generator wattage charts: the label on your own appliance (or its EnergyGuide sticker) gives the exact figure.
What size generator do I need for a space heater?
Plan for at least 1,800 W: 1,500 W to get through the start-up surge, plus a 20% margin so the generator never runs flat out. Of the common sizes, a 2,000 W generator is the smallest that fits.
| Generator | Can it run a space heater? |
|---|---|
| 2,000 W | Yes |
| 3,500 W | Yes |
| 5,000 W | Yes |
| 7,500 W | Yes |
| 10,000 W | Yes |
| 15,000 W | Yes |
How long will a power station run a space heater?
Running continuously at 1,500 W, assuming 85% of the battery is usable. The station's AC output must also handle the 1,500 W start-up surge.
| Battery capacity | Runtime |
|---|---|
| 1,000 Wh | about 34 min |
| 2,000 Wh | about 1 h |
| 3,600 Wh | about 2 h |
Running more than one appliance?
Starting surges don't add up the way running watts do. Pick everything you want to power to get your real number.
Open the Generator Size Calculator for Your HomeFrequently asked questions
What size generator do I need to run a space heater?
At least 1,800 W: 1,500 W to cover the start-up surge, plus a 20% safety margin.
Can a 2,000 watt generator run a space heater?
Yes. 2,000 W covers its 1,500 W starting surge with room to spare.
Can a 3,500 watt generator run a space heater?
Yes. 3,500 W covers its 1,500 W starting surge with room to spare.
How long will a 1,000 Wh power station run a space heater?
About 34 min, assuming 85% usable capacity, as long as the station's AC output is rated for 1,500 W of surge.
Never run a generator indoors or in a garage: see the CPSC safety guide.