How Much Does It Cost to Run a Window Air Conditioner Today?

Source: Planning watts of 900 and 8 hours a day, hours of running time on a hot day. Price: 17.23 cents per kWh, the 2025 US residential average from EIA Form EIA-861.

The monthly cost is 25% of the $150.68 average US electric bill. Because it runs only about 4 months a year, the yearly cost is 4 times the monthly figure, not twelve.

One figure cannot fit every home. These three cases show how much the answer moves with the equipment and the hours.

The lowest case costs $21 a month and the highest $103. Use the calculator above to match your own.

The same window air conditioner costs different amounts depending on the state, because the price per kWh differs. Here are the three cheapest states, the US average and the three costliest, for the same 219 kWh a month.

Source: U.S. Energy Information Administration, Form EIA-861 (final 2025 data). Price is residential revenue divided by sales and includes fixed charges.

See electricity rates in every state to find your own.

A window unit has its own compressor and fan in one case. Its label lists the cooling capacity in BTU, and a larger number means a larger draw. Many units list amps, and amps times 120 volts gives the maximum watts.

Cooling capacity sets the draw, from about 500 watts for a small 5,000 BTU unit to 1,500 watts for a large one. A unit that is too small runs all day, and one that is too large cycles often and wastes energy.

For scale, the EIA Residential Energy Consumption Survey found the average US home used about 171 kWh a month on air conditioning in 2020, and the average detached house about 209 kWh. These averages include homes with no such equipment, so a home that has it uses more.

The range for this kind of appliance runs from about 500 to 1,500 watts. At 8 hours a day that is $21 to $63 a month, which is why checking the label on yours is worth the minute.

• Match the unit size to the room, not to the price.
• Seal the gaps around the window frame with weatherstripping.
• Use the energy saver or sleep setting overnight.

Next step: Portable air conditioner costs. For general ideas, read how to lower your electric bill.

Other appliances in the cooling group: Air Conditioner, Central Air Conditioner, Portable Air Conditioner, Ceiling Fan, Mini-Split Heat Pump, Whole-House Fan.

The cost is watts divided by 1,000, times hours, times your price per kWh. The 900 watts is a planning figure for this kind of appliance, set from typical product ratings, and the 8 hours is an assumed day of use. Neither is copied from a federal table. Federal guidance describes the method and warns that real wattage varies, so we publish our own typical ranges and label them as such. Prices come from EIA Form EIA-861 for 2025.

The calculation is the standard one used in the U.S. Department of Energy's consumer guidance on estimating appliance energy use. Wattage varies by product age and features, so the label on your own appliance beats any average. Read more in our methodology.