What Size Generator Do I Need to Run a Space Heater?
Honda's radiant heater lists the same watts for start and run.
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Running and starting watts
| Load | Running watts | Starting watts | Source |
|---|---|---|---|
| Radiant heater | 1,300 | 1,300 | Honda |
| Space heater | 750–1,500 | Not listed | Champion |
Honda's wattage guide lists starting watts, then running watts. Champion's chart lists running watts, then starting watts. This table puts every figure in the Running and Starting columns. Not listed means that source does not give a separate starting figure.
How to size it
Add the running watts of every load that will be on together, then add the single highest starting surge (Generac; Honda). Generac notes that starting watts are often 2–3 times running watts, and that standby units should get a dealer survey.
Do not invent a start for the Champion row. Honda's radiant heater already sets start equal to run at 1,300 W. A gas furnace blower is a different load, with a 1/2 hp start as high as 2,350 W.
Check a full load list on the generator size calculator.
Run the generator outdoors only, 20 ft from the house (CPSC).
FAQ
Does a space heater surge when it turns on?
Honda lists 1,300 W for both start and run. Champion lists 750–1,500 W and no separate start.
Will a Honda EU2200i run a 1,500 W heater?
Yes. 1,500 W is under the EU2200i rated output of 1,800 W. The maximum is 2,200 W.
Can I run two heaters?
Only if the combined running watts still clear the generator rating. One heater on Champion's chart can already be 1,500 W, and the EU2200i is rated 1,800 W.
Is a furnace fan the same as a space heater?
No. Honda lists a 1/2 hp furnace fan at 875 W running and 2,350 W starting. Use the furnace page for that motor.
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