AC Runtime Cost (Summer) Calculator
See what running your air conditioner costs each day, month and over the whole cooling season at your electricity rate.
How it works
kWh/day = power (kW) × hours/day · cost/day = kWh/day × rate · season cost = cost/day × days
Cooling cost is simply the power the unit draws times the hours it runs times your electricity rate. The number that surprises people is runtime: a central AC cycling on and off may run its compressor only 6–10 hours across a hot day, not 24. Use the compressor’s real run time rather than clock hours, and remember a higher thermostat setpoint both shortens runtime and lowers each hour’s load.
Worked example
A 3.5 kW central AC running 8 hours a day uses 3.5 × 8 = 28 kWh/day. At 17¢/kWh that’s $4.76 a day, about $143 a month, and roughly $571 across a 120-day cooling season.
Frequently asked questions
How do I find my AC’s power draw in kW?
Check the nameplate for watts or amps (kW = volts × amps ÷ 1000), or estimate from tonnage: a rough rule is about 1–1.3 kW per ton of cooling, so a 3-ton central unit draws roughly 3.5 kW.
Does a higher SEER unit really cut my bill?
Yes — SEER measures cooling delivered per watt-hour. Replacing a SEER-10 unit with a SEER-16 one cuts energy for the same cooling by about (1 − 10/16) ≈ 38%, which shows up directly as lower kW and runtime here.
What’s the cheapest way to cut cooling cost?
Raise the setpoint a few degrees (about 3% saved per °F), use ceiling fans so you feel comfortable warmer, shade sun-facing windows, and service the unit so the coils and filter aren’t forcing it to run longer.
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This calculator is for educational purposes. Double-check important results before acting on them.