How much does it cost to run a window air conditioner?
We've pre-filled a typical window air conditioner below. Set your electricity rate and adjust the hours to match how you use yours — the cost updates instantly.
A window unit pulls about 500W (small) to 1,500W (large) while the compressor runs.
Running a window AC unit at 1,000W for 8 h a day costs about
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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.
What different sizes of window air conditioner draw
The typical figure above is a middle-of-the-road unit. Since a window air conditioner is sold by cooling capacity (BTU), here's the running power to expect across the common sizes — set the wattage to match yours for an exact cost.
| Cooling capacity | Typical running power | |
|---|---|---|
| 5,000 BTU | 500W | small bedroom or office up to ~150 sq ft |
| 8,000 BTU | 785W | medium room up to ~350 sq ft |
| 10,000 BTU | 980W | large room or small open living area up to ~450 sq ft |
| 12,000 BTU | 1,180W | large living room up to ~550 sq ft |
| 15,000 BTU | 1,470W | large open area or studio apartment up to ~700 sq ft |
Common questions
How much does it cost to run a window air conditioner per month?
At a typical 1,000W and about 8 hours a day, a window air conditioner costs roughly $41 a month at $0.17/kWh. Set your own rate and hours above for an exact figure.
How can I cut the cost of running a window air conditioner?
Use the 'eco'/auto-fan mode so the fan stops when the compressor isn't cooling.
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