AC Running Cost Calculator

How to estimate AC running cost

Use electrical input power rather than cooling capacity. Enter realistic daily operating hours and the number of days you expect to use the system.

Formula and methodology

Daily energy is input power in kW × hours used. Monthly energy is daily energy times usage days. Cost is energy times the USD per-kWh rate; the annual figure assumes twelve identical months.

Worked example

A 1.2 kW unit running eight hours per day for 30 days uses 9.6 kWh daily and 288 kWh monthly. At $0.18 per kWh, estimated cost is $1.73 per day, $51.84 per month, and $622.08 per year.

Assumptions and limitations

Compressors cycle and variable-speed systems modulate, so nameplate power multiplied by time can overstate consumption. Weather, thermostat settings, insulation, maintenance, tiered pricing, taxes, and fixed fees can change actual bills. Measured average power gives a better estimate.