AC Running Cost Calculator
Find out what your air conditioner costs to run. Choose its size, enter its SEER efficiency rating and how many hours it runs, and see the cost per hour and per month.
- Cost per hour
- $0.48
- Average power draw
- 2.57 kW
- Energy per month
- 617 kWh
What you will need
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How this calculator works
SEER (Seasonal Energy Efficiency Ratio) is the cooling delivered in BTU per watt-hour of electricity over a cooling season. Average power in kW = BTU per hour ÷ SEER ÷ 1,000.
Monthly energy = average kW × hours per day × days, and cost = energy × your electricity rate (U.S. average 18.56¢/kWh, EIA March 2026). One ton of cooling is 12,000 BTU per hour.
Real costs depend on the weather, your thermostat setting and the home’s insulation. Hours here mean hours the compressor actually runs, not hours the system is switched on.
Example: a 3 ton (36,000 BTU) central AC, SEER 14, 8 hours a day
- Average power: 36,000 ÷ 14 ÷ 1,000 = 2.57 kW.
- Energy per month: 2.57 × 8 × 30 = 617 kWh.
- Cost at 18.56¢/kWh: 617 × $0.1856 = about $115 a month.
Tips before you buy
- Raising the thermostat a few degrees and using ceiling fans cuts run time noticeably.
- Replacing a SEER 10 unit with a SEER 16 unit cuts cooling electricity by about 38%.
- Check your state’s electricity rate in the electric bill calculator for a more precise result.
Common sizes
Guides
Frequently asked questions
How much does it cost to run central air per month?
A 3 ton SEER 14 central AC running 8 hours a day uses about 617 kWh a month — about $115 at the U.S. average rate.
How many watts does an air conditioner use?
On average, BTU ÷ SEER. A 12,000 BTU unit with SEER 14 averages about 860 W; a 3 ton central unit about 2,600 W.
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Last updated October 26, 2026