How much does it cost to run a window air conditioner?
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Typical power 1,000W
Usual range 500–1,500W
Category Heating & cooling
A window air conditioner is much cheaper to run than central air because it only cools the room it's in — but run one in a bedroom every night through summer and the cost adds up. A mid-size unit draws around 1,000W while the compressor is on, cycling with the thermostat.
The cheapest window-AC habit is to cool only occupied rooms and let the rest of the house be warm, which is exactly the thing whole-house systems can't do.
What drives the cost of running a window air conditioner
- Bigger units (more BTU) pull more watts — a 12,000 BTU unit roughly doubles a small bedroom one.
- The compressor cycles, so real cost depends on how warm the room is kept and how hot it is outside.
- An old unit with a low EER badge uses more watts for the same cooling.
How to cut it
- Use the 'eco'/auto-fan mode so the fan stops when the compressor isn't cooling.
- Set it a couple degrees higher and pair it with a fan — you'll feel the same for far fewer watts.
- Seal the gaps around the unit so it isn't re-cooling warm air leaking in.
- Only cool rooms you're using; a timer that shuts it off after you fall asleep saves hours.