Know it before the bill arrives.
AC Running Cost Calculator
Calculate your air conditioner's running cost per hour, day, week, month and year from its rated power in kW, or from BTU and EER/SEER efficiency, usage and electricity rate.
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Calculate your running cost
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Fill in the unit's BTU rating, efficiency, usage and electricity rate, then press Calculate cost for a full per-hour, per-day, per-month and per-year breakdown.
All calculations run locally in your browser. Your inputs are never sent to a server.
A practical answer, before the long explanation.
Enter rated electrical power directly when the nameplate lists kW, or derive it from cooling capacity and efficiency. The calculator then applies runtime and your per-kWh rate.
Find the BTU & efficiency
Cooling capacity in BTU/h and the EER or SEER rating from the unit's nameplate — or estimate capacity from room size.
Add your usage
Hours per day, days per week, and the cooling months per year the unit actually runs.
Apply your rate
Multiply the energy by your per-kWh price and compare hourly, daily, monthly and seasonal costs.
What this estimate assumes
This calculator derives power draw from cooling capacity and efficiency using the standard formula: Power (kW) = BTU/h ÷ EER ÷ 1,000.
EER vs SEER: EER measures instantaneous efficiency at a single operating condition (95°F outdoor, 80°F indoor). SEER measures seasonal average efficiency across a range of outdoor temperatures (65–104°F). When SEER is selected, the calculator produces a seasonal average power-draw estimate — actual peak draw on the hottest days will be higher, and off-peak draw will be lower. This is a planning approximation, not an instantaneous meter reading.
The monthly figure uses 52 weeks ÷ 12 as a running average, and the yearly figure reflects only the cooling months you enter. Fixed bill charges, taxes, and delivery fees are not included, and thermostat habits and room insulation change real-world usage.
The CO₂ estimate uses the average U.S. grid intensity of about 0.386 kg CO₂ per kWh (EPA eGRID). Rates and results are estimates for planning, not professional energy or financial advice — always check your own bill.
The formula
Power draw (kW) = BTU/h ÷ EER ÷ 1,000
Daily energy (kWh) = power draw × hours/day
Cost = energy (kWh) × rate (per kWh)
Worked example: a 12,000 BTU split AC with an EER of 11.5 running 8 hours a day, 7 days a week, for 6 cooling months at $0.17/kWh draws about 1.04 kW, costs roughly $1.42 per day, $43.05 per month and $258.28 for the cooling season.
Guides worth reading
Air Conditioner Running Costs: How to Calculate and Reduce Them
What actually drives your cooling bill — power draw, runtime, tariff and efficiency — plus the highest-impact ways to cut it without losing comfort.
Read articleBTU to kW: How to Convert Cooling Power for Cost Estimates
Nameplates mix BTU/hr, watts and EER. Here's how to translate them into the power figure your cost estimate needs.
Read articleInverter vs Non-Inverter AC: Which Saves More on Electricity Bills?
A straight comparison of running costs, purchase prices and payback periods — with a framework you can apply to your own household.
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