September 7, 2026
How much does it cost to run a window air conditioner?
Kısa cevap
A typical 10,000 BTU window air conditioner draws about 900-1,100 watts and uses roughly 7-9 kWh over an 8-hour day. At the 2025 U.S. average residential rate of about 17 cents per kWh, that works out to around $1.20-1.50 a day, or $35-45 a month. Your real cost depends heavily on your state's rate — from about 11 cents per kWh in Idaho and Utah to 30 cents or more in California and Hawaii — plus how many hours a day you run it and how hard it has to work. Enter your own state, hours and days in the calculator below for an exact figure.
A window air conditioner is the cheapest way to cool a single room, but "cheap to buy" and "cheap to run" aren't the same thing. What it costs you every month comes down to three numbers: how much power the unit draws, how many hours it runs, and what your utility charges per kilowatt-hour.
What a window unit actually draws
Window ACs are usually sized between 5,000 and 12,000 BTU. As a rough guide:
- 5,000-6,000 BTU (up to ~250 sq ft): 450-600 watts
- 8,000-10,000 BTU (250-450 sq ft): 700-1,100 watts
- 12,000-14,000 BTU (450-550 sq ft): 1,100-1,500 watts
Those are running watts while the compressor is on. Modern units with an Energy Star rating and a variable-speed compressor pull noticeably less than older single-speed models of the same BTU rating, and they spend more time coasting at low power once the room is cool.
Your rate matters more than your unit
Electricity prices vary more between states than window AC models vary between each other. The 2025 U.S. residential average is about 17 cents per kWh, but the spread is wide: roughly 11 cents in Idaho, Utah and Nebraska, the high teens across most of the Midwest and South, and 30 cents or more in California, Massachusetts and Hawaii. A 10,000 BTU unit that costs $35 a month to run in Texas can cost $60+ in the Northeast for the exact same usage.
A worked example
Take a 10,000 BTU unit drawing 1,000 watts, running 8 hours a day for 30 days:
- Daily: 1,000 W x 8 h = 8 kWh -> about $1.36 at 17 cents/kWh
- Monthly: 240 kWh -> about $41
- Over a 4-month cooling season: roughly $160
Run it 24/7 in a heat wave and the monthly figure triples. Drop the thermostat setting a few degrees and it climbs again, because the compressor cycles longer to hold the lower temperature.
Run your own numbers
The calculator below uses your state's current residential electricity rate. Pick your state, set the BTU size, and adjust the hours and days to match how you actually use the unit — you'll get daily, monthly and yearly cost instantly. If you're weighing a window unit against central air, our main AC calculator and the United States tariff page let you compare both on the same rate.