Window Air Conditioner running cost, by state
A window air conditioner drawing 900W costs about $339 a year at the US average electricity rate — but that average hides a fourfold spread. Pick your state for a real figure.
At the US average rate
900W at a 70% duty cycle, 8 hours a day, at 18.44¢/kWh.
About this appliance
A single-room window unit typically draws 500 to 1,440 watts. Because it cools a small space, the duty cycle is often lower than a central system, which is why one window unit is usually cheaper than cooling a whole house - but three of them rarely are.
- Nameplate wattage is not running cost. This window air conditioner draws about 900W when active, but cycles roughly 70% of the time it is switched on, so effective consumption is near 630W.
- At typical use this is a major load - around 1,840 kWh a year. Efficiency upgrades here pay back faster than on any small appliance.
- Models vary widely, from about 500W to 1440W. Check the nameplate on your own unit rather than assuming an average, because the spread is more than 2x.
- Insulation and air sealing reduce runtime, which lowers cost more reliably than adjusting the thermostat by a degree.
- If your utility offers time-of-use pricing, shifting this load off-peak can cut its cost substantially without using any less energy.
Annual cost in every state
Sorted cheapest first. Click any state for the full calculation with that state’s rate loaded.
| State | Rate /kWh | Per month | Per year | Relative |
|---|---|---|---|---|
| Idaho | 12.35¢ | $18.95 | $227 | |
| Utah | 12.96¢ | $19.88 | $238 | |
| Oklahoma | 13.38¢ | $20.53 | $246 | |
| Nebraska | 13.59¢ | $20.85 | $250 | |
| Nevada | 13.60¢ | $20.86 | $250 | |
| North Dakota | 13.61¢ | $20.88 | $250 | |
| Missouri | 13.68¢ | $20.99 | $252 | |
| New Mexico | 14.12¢ | $21.66 | $260 | |
| Iowa | 14.14¢ | $21.69 | $260 | |
| Louisiana | 14.15¢ | $21.71 | $260 | |
| Arkansas | 14.36¢ | $22.03 | $264 | |
| Tennessee | 14.47¢ | $22.20 | $266 | |
| Montana | 14.67¢ | $22.51 | $270 | |
| Wyoming | 14.80¢ | $22.71 | $272 | |
| Washington | 14.95¢ | $22.94 | $275 | |
| Kentucky | 14.98¢ | $22.98 | $276 | |
| North Carolina | 15.09¢ | $23.15 | $278 | |
| Kansas | 15.13¢ | $23.21 | $278 | |
| Florida | 15.17¢ | $23.27 | $279 | |
| Arizona | 15.23¢ | $23.37 | $280 | |
| South Dakota | 15.73¢ | $24.13 | $289 | |
| Georgia | 15.84¢ | $24.30 | $291 | |
| Colorado | 16.16¢ | $24.79 | $297 | |
| Mississippi | 16.16¢ | $24.79 | $297 | |
| South Carolina | 16.18¢ | $24.82 | $298 | |
| Oregon | 16.27¢ | $24.96 | $299 | |
| Texas | 16.44¢ | $25.22 | $302 | |
| Alabama | 16.77¢ | $25.73 | $309 | |
| West Virginia | 16.80¢ | $25.77 | $309 | |
| Minnesota | 16.95¢ | $26.00 | $312 | |
| Virginia | 17.61¢ | $27.02 | $324 | |
| Indiana | 18.15¢ | $27.85 | $334 | |
| Delaware | 19.38¢ | $29.73 | $357 | |
| Ohio | 19.52¢ | $29.95 | $359 | |
| Wisconsin | 19.74¢ | $30.28 | $363 | |
| Pennsylvania | 21.55¢ | $33.06 | $396 | |
| Maryland | 21.77¢ | $33.40 | $400 | |
| Michigan | 22.01¢ | $33.77 | $405 | |
| New Jersey | 23.27¢ | $35.70 | $428 | |
| Illinois | 23.85¢ | $36.59 | $439 | |
| Vermont | 24.89¢ | $38.19 | $458 | |
| District of Columbia | 25.40¢ | $38.97 | $467 | |
| New Hampshire | 27.33¢ | $41.93 | $503 | |
| Connecticut | 27.37¢ | $41.99 | $503 | |
| Alaska | 28.23¢ | $43.31 | $519 | |
| Maine | 28.63¢ | $43.92 | $527 | |
| Massachusetts | 28.82¢ | $44.21 | $530 | |
| Rhode Island | 29.46¢ | $45.20 | $542 | |
| New York | 29.93¢ | $45.92 | $551 | |
| California | 33.25¢ | $51.01 | $612 | |
| Hawaii | 52.00¢ | $79.78 | $957 |
Common questions
How many watts does a window air conditioner use?
A typical window air conditioner draws about 900 watts while running, with most models falling between 500W and 1440W. Check the nameplate label or manual for your specific unit - the range is wide enough that averages can mislead.
How much electricity does a window air conditioner use per day?
At around 8 hours of use a day and a 70% duty cycle, that works out to roughly 5.04 kWh per day, or about 151 kWh a month. Your actual figure depends on your usage and model.
Why does the cost differ so much between states?
Residential electricity rates across the US range from about 12.35 cents per kWh in North Dakota to 46.62 cents in Hawaii - nearly a fourfold difference. The same window air conditioner, used identically, therefore costs almost four times as much to run in the most expensive state as in the cheapest.
Is it cheaper to run a window air conditioner at night?
Only if you are on a time-of-use or variable tariff. On a flat rate, the time of day makes no difference to cost. If you are on time-of-use pricing, off-peak hours are typically materially cheaper, and shifting this load can reduce its cost without reducing usage.