What Size Generator Do You Need for a Space Heater?
An electric space heater draws about 1,500 watts the whole time it's on, with no starting surge. It runs on a mid-size portable, but it uses a lot of fuel for the heat it gives.
| Appliance | Running / starting W | On its own | With fridge, lights and Wi-Fi |
|---|---|---|---|
| Space heater | 1,500 / 1,500 | 3,000-watt 10 kW standby | 3,500-watt 10 kW standby |
Smallest portable (by starting watts) and smallest standby generator on natural gas, keeping about 20% headroom.
Tips
- If you have a gas furnace, running its blower from the generator heats the whole house for half the power.
- Never run a fuel-burning heater indoors without proper venting, and keep a carbon monoxide alarm on every floor.
See also the appliance wattage chart and what each generator size can run.