Air Conditioner Running Cost Calculator: Window, Portable and Split Units
Compare window, portable and split units by BTU and runtime. Adjust the wattage, runtime and your own electricity rate below — every figure updates instantly in your browser, and nothing you type is sent anywhere.
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How this cost is calculated
The formula is kWh = watts ÷ 1000 × hours, then cost = kWh × your rate per kWh. Standing charges and tiered or time-of-use pricing are billed separately by your supplier, so treat these numbers as the marginal cost of running this appliance rather than a full bill.
For the full breakdown with regional price tables, read the detailed guide, or estimate your whole household on the home electricity bill calculator.
Frequently asked questions
How many watts does an air conditioner use?
Roughly 100W per 1,000 BTU for older units and 80-90W per 1,000 BTU for modern inverter models, so a 12,000 BTU unit draws about 1,000-1,200W.
Does running AC all night cost a lot?
A 1,200W unit running 8 hours overnight uses 9.6 kWh, about $1.54 a night at $0.16/kWh — though inverter units cycle down and often use 30-40% less.
Is a higher thermostat setting really cheaper?
Yes. Each 1°F (0.5°C) higher setting typically cuts compressor runtime by 3-5%, so 72°F to 76°F can save 12-20% of the cooling bill.