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How many watts does a window air conditioner use? (900 W)
A window air conditioner uses about 900 W
Typical range 500–1,500 watts, plus ~1 W on standby.
Typical range 500–1,500 watts, plus ~1 W on standby.
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A window AC cools one room, so it draws far less than central air but still runs for long stretches in summer.
Window air conditioner power specs
| Typical running power | 900 W |
| Typical range | 500–1,500 W |
| Startup surge | 1,800 W |
| Standby draw | 1 W |
| Energy use | 5.40 kWh/day · 162.0 kWh/mo |
What affects a window air conditioner's wattage
A window air conditioner is rated around 900 W, but the real figure shifts with a few things:
- Model and rating: A window air conditioner ranges from about 500 W on efficient units to 1,500 W on larger or older ones — a spread of ~1,000 W.
- Usage: the real draw depends on room size, target temperature and how hard the unit works.
- Startup surge: the motor can briefly spike to about 1,800 W at start-up, well above the 900 W running figure.
- Standby: even idle it keeps drawing ~1 W, which quietly adds up over a year.
- Run time: because a window air conditioner runs for long stretches (about 6 h/day), hours of use matter as much as raw wattage on your bill.
Running cost at $0.17/kWh
| Electricity rate | Per day | Per month | Per year |
|---|---|---|---|
| $0.10/kWh | $0.54 | $16.20 | $197.10 |
| $0.15/kWh | $0.81 | $24.30 | $295.65 |
| $0.20/kWh | $1.08 | $32.40 | $394.20 |
| $0.25/kWh | $1.35 | $40.50 | $492.75 |
| $0.30/kWh | $1.62 | $48.60 | $591.30 |
| $0.40/kWh | $2.16 | $64.80 | $788.40 |
See the full breakdown of what it costs to run a window air conditioner, or what size power station runs a window air conditioner.
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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