Air conditioner running cost calculator

Last updated 2026-08-28 · Last checked 2026-08-28 · 312 words · 1 min read

Pick your unit's cooling capacity (or type its input power), the hours you run it and your state, and the calculator shows the cost per hour, per day and for the period, side by side for every state and territory. Defaults use the regulated 2026–27 tariffs in force from 1 July 2026, GST inclusive; type your own rate from a bill for a closer answer.

The formula

Cost per hour = input power (kW) × duty factor × tariff ($/kWh). Input power is what the unit draws from the wall, not its cooling capacity: a 5 kW split typically draws about 1.36 kW. The duty factor (default 0.65) reflects that an inverter throttles back once the room reaches temperature; drag it to 1.0 for a scorching afternoon with the doors open, or 0.4 for overnight in a closed bedroom.

Cost per day = cost per hour × hours. Cost per period = cost per day × days. A second mode uses the annual kWh printed on the Zoned Energy Rating Label for your zone (hot, average or cold) multiplied by the tariff — that is the official annual figure and needs no duty assumption.

Default tariffs by state (from 1 July 2026, incl. GST)

Regional NSW (Endeavour 33.73, Essential 35.01) and regional Queensland (Ergon 28.90) are selectable. Regulated caps are the standing-offer maximum; market offers usually sit 3–10 c/kWh lower, so a bill rate beats the default.

Input power by unit size

For your exact model, use the "rated power input" on its Energy Rating registration or the Zoned Energy Rating Label kWh.

Limitations

There is no official duty-cycle figure for inverter units; the 0.65 default is a working assumption and is adjustable. The daily supply charge is excluded by default because you pay it whether or not the air con runs. Controlled-load and time-of-use tariffs are not modelled beyond the flat rate.

Test vectors (for the build)