Evaporative cooler vs AC: operating cost calculator

Enter your own power ratings and local tariffs in any currency. The defaults are placeholders, not typical values for your country, so replace them with numbers from your bill and the equipment nameplates.

Formulas

• Electricity cost = power (kW) × hours/day × days × price per kWh, for each system.
• Cooler water cost = water (L/h) × hours × days ÷ 1,000 × price per m³.
• Enter run-hours separately for each system. An AC cycles on and off, so if its compressor runs 60% of an 8-hour day, enter 4.8 hours. An evaporative cooler's fan usually runs continuously while cooling.

What this does not capture

• Equal comfort is assumed (a modelling simplification). In humid weather a cooler may not achieve the same comfort, so check the suitability calculator first.
• Time-of-use and tiered tariffs, demand charges, pad replacement, maintenance and installation costs.
• AC power rises in extreme heat. DOE notes conventional air-cooled condensers use about 10% more power for each 10 °F (5.6 °C) above 95 °F (35 °C).^[1]

For context, the US DOE says evaporative coolers can use about one-fourth as much energy as central air conditioners. Your result depends on your own inputs.^[1] More detail is in the operating-cost guide.