What size generator to run a space heater?
Space heater sizing at a glance: it draws 1500 running watts.
| Spec | Value |
|---|---|
| Running watts | 1500W |
| Starting (surge) watts | 1500W |
| Recommended class (this load + margin) | 2000W |
Why the startup surge matters
A space heater is a resistive load, so it has no meaningful startup surge. If you size a generator only for the running watts, it can stall the instant the space heater switches on. Always size for the surge.
Sizing the whole system
The number above covers the space heater on its own with a safety margin. In a real outage you'll run other things too — and the right method is your total running load plus the single largest surge among everything, not the sum of every surge. Use the full calculator to size your actual setup:
Common questions
How many watts does a space heater use?
A typical space heater draws about 1500 watts, with no significant startup surge.
What size generator runs a space heater?
For the space heater alone plus a safety margin, a 2000W (≈2.0kW) class generator is appropriate. Add your other essential loads to size the full system.