AC running cost calculator
See what an air conditioner costs you per month before the bill arrives, with an option for compressor running share.
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How to use it
- Enter ac capacity, efficiency (eer), hours per day, days, compressor running share and price per kwh.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Power (kW) = BTU/h ÷ EER ÷ 1000. Energy = power × hours × days × compressor share. Cost = energy × price.
Example
Inputs: AC capacity = 18,000 BTU/h, Efficiency (EER) = 12, Hours per day = 10, Days = 30, Compressor running share = 100 %. Result: Running cost: 81.00; Energy used: 450 kWh; Electrical power: 1.5 kW.
Limits and caveats
- It uses one flat price per kWh; for tiered tariffs use the electricity bill calculator.
- An AC does not run at full power all the time, so adjust the compressor share to get closer to reality.
Questions about this tool
How much power does an 18,000 BTU AC use?
At EER 12 it draws about 1.5 kW, or 15 kWh over 10 hours of continuous running.
What is the compressor running share?
It is the share of time the compressor actually runs, since the unit cycles off once the room reaches the set temperature.
Is an inverter AC cheaper to run?
Usually yes, because it slows down instead of cycling; model that by lowering the compressor share.