How Much Does It Cost to Run central air conditioning?
A typical central AC uses about 3,500 watts, which costs about $0.63 per hour. Used 8 hours a day, that is $5.04 per day, $153 per month and about $1,840 per year at the US average of about 18 cents per kWh. Change the numbers below for your own model and rate.
Typical estimate: 8 hours of compressor running time a day in summer for a 3-ton system. These are typical estimates – check your own label or use a plug-in meter for exact figures.
Central AC running cost by electricity rate
Rates vary widely across the country. $0.12 is typical of low-cost areas, $0.18 is about the national average, and $0.25–$0.35 or more is common in high-cost areas such as parts of California, New England and Hawaii.
| Rate per kWh | Per hour | Per day | Per month | Per year |
|---|---|---|---|---|
| $0.12 | $0.420 | $3.36 | $102.21 | $1,226 |
| $0.18 | $0.630 | $5.04 | $153.32 | $1,840 |
| $0.25 | $0.875 | $7.00 | $212.94 | $2,555 |
| $0.35 | $1.225 | $9.80 | $298.12 | $3,577 |
Based on 3,500 W for 8 h/day; month = 30.42 days.
Cost by hours of use per day
| Hours per day | kWh per month | Per day | Per month | Per year |
|---|---|---|---|---|
| 4 h | 426 | $2.52 | $76.66 | $920 |
| 8 h | 852 | $5.04 | $153.32 | $1,840 |
| 12 h | 1,278 | $7.56 | $229.98 | $2,759 |
At 18 cents per kWh and 3,500 W.
Low, typical and high wattage
A 2–4 ton system typically draws roughly 2,000–5,000 W including the outdoor unit and blower; a 3-ton unit is often around 3,500 W.
| Case | Watts | Per hour | Per month | Per year |
|---|---|---|---|---|
| Low | 2,000 | $0.360 | $87.61 | $1,051 |
| Typical | 3,500 | $0.630 | $153.32 | $1,840 |
| High | 5,000 | $0.900 | $219.02 | $2,628 |
At 8 h/day and 18 cents per kWh.
How it is calculated
3,500 W × 8 h ÷ 1,000 = 28 kWh per day
28 kWh × $0.18 = $5.04 per day
$5.04 × 30.42 days = $153.32 per month
How to cut the cost of running central air conditioning
- Raise the thermostat 2–3°F while away. Each degree you do not cool shortens compressor runtime across the day.
- Check the air filter monthly during cooling season and replace it when dirty (at least every 3 months). A clogged filter forces the blower to work harder and can ice up the coil.
- Keep the outdoor condenser clear of leaves and at least a couple of feet from shrubs, and hose the fins gently each spring.
- Seal and insulate ducts running through the attic – leaky ducts can lose a large share of the cooled air before it reaches a room.
Frequently asked questions
How much does it cost to run central air conditioning per month?
At 18 cents per kWh, a typical 3,500 W central AC used 8 hours a day costs about $153.32 per month (852 kWh). That is about $1,840 a year.
How much does it cost to run central air conditioning per hour?
About $0.630 per hour at 18 cents per kWh, or $1.225 per hour if you pay 35 cents per kWh. Multiply by your hours of use to estimate any day.
Why does the cost of central air conditioning vary so much?
Wattage varies by model and setting – from 2,000 W to 5,000 W here. At the same 8 hours a day and 18 cents per kWh, that is $88 to $219 per month. Your electricity rate matters just as much: at 35 cents per kWh the typical unit costs $298 per month.