Window air conditioner electricity use: cost per hour and month
Window air conditioner electricity use: a median certified 8,000 BTU unit uses 0.53 kWh per hour of cooling. Enter your hours and state: the tool gives the cost of your month.
Example for an 8,000 BTU unit, 8 hours a day for 30 days — change any figure to see your own result
Cooling cost for the hours you enter
$23
8 hours a day for 30 days, median certified 8,000 BTU window unit, at the U.S. average price
| Per hour of cooling | $0.10 |
| Energy per hour | 0.53 kWh (about 533 watts) |
| Certified models of that size | 121, 373 to 454 kWh in the 750-hour test |
| Most frugal of them, same hours | $22 |
The DOE test counts 750 hours of cooling a year. A hotter room or a higher setting runs the compressor longer.
Compiled by Radif Partners · How the figures are built
Window air conditioner electricity use depends on the size of the unit, its efficiency and the hours it runs. The ENERGY STAR list of November 12, 2026 gives a yearly kWh for each of 527 certified window units, measured under the federal test, which counts 750 hours of cooling a year (10 CFR 430, appendix F). Divided by those hours, the yearly figure gives the energy per hour of cooling. A median certified 8,000 BTU unit uses 0.53 kWh an hour, about 533 watts, and a median 12,000 BTU unit 0.8 kWh. At the U.S. average home price of August 2026, eight hours a day for 30 days costs $23 for the 8,000 BTU unit and $35 for the 12,000 BTU unit. In Hawaii, the most expensive state, the same month with the smaller unit costs $60. Within one size, the most frugal certified model uses less than the median; the tool shows that gap for your hours. Real use depends on the heat outside, the room and the thermostat.
Window air conditioner electricity use by size
The table gives, for each common size, the number of certified window units within 5% of that rating, their median yearly kWh in the test, the energy per hour of cooling and the cost of a month at eight hours a day.
| Size | Models | Typical kWh in the test | kWh per hour | Month, 8 h a day, U.S. average | Same month, Hawaii |
|---|---|---|---|---|---|
| 5,000 BTU | 20 | 260 | 0.35 | $15 | $39 |
| 6,000 BTU | 31 | 328 | 0.44 | $19 | $50 |
| 8,000 BTU | 121 | 400 | 0.53 | $23 | $60 |
| 10,000 BTU | 102 | 500 | 0.67 | $29 | $75 |
| 12,000 BTU | 121 | 600 | 0.8 | $35 | $91 |
| 14,000 BTU | 39 | 689 | 0.92 | $40 | $104 |
| 18,000 BTU | 28 | 900 | 1.2 | $52 | $136 |
| 24,000 BTU | 34 | 1,353 | 1.8 | $79 | $204 |
From yearly test figure to your bill
The yearly kWh on the list is not a forecast of your use: it is the energy of 750 hours of cooling at test conditions, set by appendix F to the federal test procedure. Dividing it by those hours gives a fair per-hour figure for comparing units and for estimating your own hours. A unit in a sunny west window on a hot afternoon runs its compressor more than in the test; in mild weather it cycles off and uses less. Count the hours the unit is actually switched on and cooling.
Your hours of cooling, priced in your state
Example for an 8,000 BTU unit, 8 hours a day for 30 days — change any figure to see your own result
Cooling cost for the hours you enter
$22
6 hours a day for 30 days, median certified 10,000 BTU window unit, at the U.S. average price
| Per hour of cooling | $0.12 |
| Energy per hour | 0.67 kWh (about 667 watts) |
| Certified models of that size | 102, 405 to 546 kWh in the 750-hour test |
| Most frugal of them, same hours | $18 |
Efficiency: what the list rates
The list gives each unit a combined energy efficiency ratio, cooling delivered per unit of power including standby. A higher ratio means less energy for the same cooling. Units with a variable speed compressor, which the list flags, can slow down instead of stopping and restarting. In the tool, the line "most frugal of them" shows what the best certified unit of your size would cost for the same hours.
Other cooling and drying costs
A humid basement or a room that stays damp after cooling often needs a dehumidifier, whose running cost is on the dehumidifier page. The state comparison gives the price per kWh in every state, the figure that multiplies every result on this page.