How Much Does It Cost to Run AC Per Month?

The Short Answer

Running a central AC unit costs approximately $100-$200 per month depending on usage and electricity rates. A 3-ton unit running 8 hours daily at $0.15/kWh costs about $130/month.

The Detailed Breakdown

Monthly cost calculated as wattage x hours per day x 30 days x electricity rate per kWh.

CalculationValueAssumptions
Monthly AC Cost$129.603.6 kW x 8 hrs x 30 days x $0.15/kWh
Daily AC Cost$4.323.6 kW x 8 hours x $0.15/kWh
Summer Season Cost$518-$7784-6 months of AC usage

Key Assumptions

  • 3-ton central AC unit draws approximately 3.6 kW.
  • National average electricity rate of $0.15 per kWh.
  • Average runtime of 8 hours per day during summer months.

Adjust for Your Situation

Expect to pay about $130/month for central AC; smart thermostat use can cut this by 15-20%.

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What Affects This Result

Thermostat Setting

Each degree below 78F increases cooling costs by 3-5%.

Home Insulation

Poor insulation can double cooling costs by forcing longer run times.

Unit Efficiency

A high-SEER unit (18+) uses 30-40% less energy than an older unit (10 SEER).

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