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Air Conditioner Cost Estimator

Air conditioners cycle and change output, so this estimator includes an adjustable average running fraction rather than assuming full rated draw all day.

Estimate air-conditioner energy cost

Enter your own values. Use the currency that matches the rate you provide.

Use electrical input from the rating label—not cooling capacity in BTU/h.
Count the daily period the unit is expected to be available.
A planning assumption from 1% to 100%; actual cycling varies.
Typical monthly days of use.
Use your billed energy rate.
Formula used
Estimated average input = rated input × running fraction. Monthly kWh = average kW × switched-on hours × days.

Why operating hours are not the whole story

An air conditioner may be switched on for eight hours but draw its rated input power for only part of that time. A fixed-speed compressor can cycle on and off; an inverter system can vary its speed; both respond to outdoor temperature, room heat gain, insulation, set temperature, airflow, and sizing. The running fraction is therefore a planning assumption, not a universal value.

Choose defensible inputs

Look for rated electrical input power in watts on the nameplate. Some product labels prominently display cooling capacity in BTU per hour or kilowatts of cooling. Cooling capacity is not the same as electrical input; do not enter it as watts. If only an energy-efficiency label is available, consult the manufacturer's rated input data or measure consumption with a suitable meter installed and used safely.

For a quick sensitivity check, calculate a low, middle, and high running-fraction scenario. A higher percentage represents more average compressor operation. If the room is poorly insulated or the weather is unusually hot, the actual result may approach the higher case.

Ways to compare changes

  • Compare two daily schedules while keeping the running fraction unchanged.
  • Check how a different thermostat setting or shaded room might alter the assumed running fraction, without treating a guessed change as measured fact.
  • Keep filters clean, maintain clear airflow, close doors and windows while cooling, and have equipment serviced according to its manual.
This is an energy-planning estimate, not an HVAC sizing tool. For electrical work, refrigerant issues, or equipment sizing, use an appropriately qualified professional.

Related tools and guides

For the basic relationship between watts and kWh, read Watts vs. kilowatt-hours. You can also use the Home Energy Planner to combine several devices in one estimate.