How much does a window air conditioner cost per month in Missouri?

About $9.27 a month, assuming 900 W at a 80% duty cycle, 8 hours a day, 120 days a year at 16.09¢/kWh.

How many kilowatt-hours does a window air conditioner use?

Roughly 691 kWh a year under these assumptions, or 0.72 kWh for every hour it runs.

Is that expensive compared with other states?

Missouri has the 25th cheapest average residential rate in the country, so this appliance costs less here than the U.S. average of $127 a year.

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Cost to run a window air conditioner in Missouri (July 2026 rates)

At 16.09¢ per kilowatt-hour — Missouri's average residential price in July 2026 — running a window air conditioner costs $111 a year. That is 12% less than the national average of $127. Missouri's residential rate is up 3.4% from July 2025, which moves this appliance from $108 to $111 a year.

Per hour: 11.6¢
Per day of use: 92.7¢
Per month: $9.27
Per year: $111

Assumption: 900 W at a 80% duty cycle, 8 hours a day, 120 days a year — 691 kWh a year. Typical of a 10,000 BTU window unit. Small 5,000 BTU units draw closer to 500 W; 15,000 BTU units closer to 1,400 W. Use the calculator to swap in the numbers from your own model.

How Missouri compares

Missouri pays 16.09¢/kWh, the 25th cheapest residential electricity of the 51 U.S. jurisdictions EIA reports. For this appliance that works out to $15.34 less a year than the typical U.S. household pays for the same use. Running the same window air conditioner costs $87.92 a year in Louisiana and $332 in Hawaii, so where you live changes this bill by $244 a year.

State	Rate	Per month	Per year
Oregon	15.97¢	$9.20	$110
Iowa	15.99¢	$9.21	$111
Missouri	16.09¢	$9.27	$111
New Mexico	16.09¢	$9.27	$111
Georgia	16.27¢	$9.37	$112

States ranked by average residential price, cheapest first. See all 51 states for a window air conditioner.

What else costs about the same in Missouri

Electric clothes dryer$126 a year in MO Aquarium$95.14 a year in MO Gaming pc$93.97 a year in MO

Cutting the number down

Sealing the gaps around the sleeve with foam matters more than the unit's efficiency rating. Warm air leaking back in is load you pay to remove twice.
An inverter model modulates instead of slamming on and off, which shows up as a lower effective duty cycle rather than a lower nameplate watt.
Shading the outdoor half of the unit lowers the temperature it rejects heat into, which lowers the work it has to do.

Questions

How much does a window air conditioner cost per month in Missouri?: About $9.27 a month, assuming 900 W at a 80% duty cycle, 8 hours a day, 120 days a year at 16.09¢/kWh.
How many kilowatt-hours does a window air conditioner use?: Roughly 691 kWh a year under these assumptions, or 0.72 kWh for every hour it runs.
Is that expensive compared with other states?: Missouri has the 25th cheapest average residential rate in the country, so this appliance costs less here than the U.S. average of $127 a year.