Electricity Cost Calculator · Practical guide
Cost to Run a Window Air Conditioner Per Month
A mid-size window AC draws 700-1,100 watts and typically costs $22 to $34 per month when run 8 hours a day at $0.13 per kWh.
At a glance
The Short Answer
A typical 8,000 BTU window air conditioner draws about 700 watts. Run it 8 hours a day for 30 days and it uses 168 kWh, costing about $21.84 per month at $0.13 per kWh. Smaller bedroom units can run under $16 a month, while large 15,000 BTU units can approach $47.
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Electricity Cost Breakdown
| Appliance | Monthly kWh | Monthly Cost |
|---|
Monthly Cost by Unit Size
Estimates below assume 8 hours of daily use, 30 days per month, and $0.13 per kWh.
| Unit Size | Typical Wattage | Monthly kWh | Monthly Cost |
|---|---|---|---|
| 5,000 BTU | 500 W | 120 | $15.60 |
| 8,000 BTU | 700 W | 168 | $21.84 |
| 12,000 BTU | 1,100 W | 264 | $34.32 |
| 15,000 BTU | 1,500 W | 360 | $46.80 |
What Drives Your Actual Cost
Three things matter most: your local rate (at $0.20 per kWh, add roughly 54% to the figures above), how many hours the compressor actually runs, and the unit's efficiency rating. A hot, humid climate keeps the compressor cycling almost constantly, while a shaded, well-insulated room lets it rest. High-efficiency units with a CEER of 12 or better can cut these costs by 15-25%.
Tips to Lower Cooling Costs
- Size the unit to the room — an oversized AC short-cycles and wastes power.
- Clean the filter monthly during cooling season.
- Use a timer or smart plug so the unit does not run in an empty house.
- Close blinds on sun-facing windows to reduce the heat load.
Enter your unit's exact wattage and your actual daily runtime above for a precise monthly and annual estimate.
Frequently Asked Questions
How do I find my window AC's wattage?
Check the specification sticker on the side of the unit or the owner's manual. You can also estimate it: watts roughly equal BTU divided by the efficiency rating (EER or CEER), so an 8,000 BTU unit with a CEER of 11 draws about 730 watts.
Is a window AC cheaper to run than central air?
Yes, when cooling a single room. Central systems often draw 3,000-5,000 watts to cool a whole house, so one window unit at 700 watts is far cheaper if you only need one room cooled.
Does fan-only mode save electricity?
Significantly. The fan alone draws roughly 50-100 watts versus 700 or more with the compressor on, so fan mode can cut usage by about 90% while still circulating air.
How much does a window AC add to a summer electric bill?
One mid-size unit run 8 hours daily adds about $22-$35 per month at average rates. Running two or three units around the clock in a hot climate can add $100 or more.