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What size generator or power station for a window air conditioner? (1,150+ W)
To run a window air conditioner, choose at least
1,150 W running · 1,800 W startup surge.
1,150 W running · 1,800 W startup surge.
A window air conditioner draws about 900 W while running, but its motor can spike to roughly 1,800 W at startup, so size for the surge. Pick a generator, inverter or power station rated comfortably above these numbers.
Battery runtime calculator
Estimated runtime—
Assumes about 85% usable capacity. Motors need extra headroom for startup surge.
How long a power station lasts
| Power station | Estimated runtime |
|---|---|
| 300 Wh | 0 h 17 min |
| 500 Wh | 0 h 28 min |
| 1,000 Wh | 0 h 57 min |
| 2,000 Wh | 1 h 53 min |
| 3,000 Wh | 2 h 50 min |
Sizing guide
| Minimum running watts | 1,150 W |
| Minimum starting watts | 1,800 W |
| Suggested inverter | 1,800 W or higher |
See also window air conditioner wattage and running cost.
FAQ
How many watts does a window AC use?
Around 500-1500 watts depending on the cooling capacity (BTU rating).
What size generator runs a window AC?
Plan for the startup surge - many need 1500-2000 starting watts even if running watts are lower.
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