How Much Does It Cost to Run an Air Conditioner? (2026, by Size, SEER and State)
What your air conditioner actually costs to run, worked out from real electricity rates for every state.
By Mark Curant·Updated
Quick answer
At the U.S. average residential electricity rate of 18.31¢/kWh (July 2026), a typical 3-ton central air conditioner (SEER 14) costs about $0.47 per hour, $113 for a summer month at 8 hours a day, and about $706 a year at 1,500 cooling hours. Where you live changes that a lot: the same hour costs $1.23 in Hawaii and $0.33 in Louisiana.
I run several stores in the Caribbean, where electricity costs almost double the U.S. average and the AC never really gets a day off. At those prices you learn quickly that the cost of cooling comes down to three numbers: how big the system is, how efficient it is, and what you pay per kilowatt-hour. Below are all three, worked out for every state.
The formula
Cost = kW × hours of running × electricity rate ($/kWh)
Example: a 3-ton SEER 14 system draws 3 × 12 ÷ 14 = 2.57 kW. One hour at 18.31¢/kWh costs 2.57 × 0.1831 = $0.47. Your electricity rate is on your bill as cents per kWh; if your bill lists several charges, divide the total by the kWh used.
Cost to run central air by size (U.S. average rate)
| System size | Power draw (SEER 14) | Per hour | Summer month (8 hrs/day) | Per year (1,500 hrs) |
|---|---|---|---|---|
| 1.5 ton | 1.29 kW | $0.24 | $56 | $353 |
| 2 ton | 1.71 kW | $0.31 | $75 | $471 |
| 2.5 ton | 2.14 kW | $0.39 | $94 | $589 |
| 3 ton | 2.57 kW | $0.47 | $113 | $706 |
| 3.5 ton | 3.00 kW | $0.55 | $132 | $824 |
| 4 ton | 3.43 kW | $0.63 | $151 | $942 |
| 5 ton | 4.29 kW | $0.78 | $188 | $1,177 |
How efficiency (SEER) changes the cost
A 3-ton system at 1,500 hours a year and 18.31¢/kWh:
| SEER | Per hour | Per year | vs. SEER 10 |
|---|---|---|---|
| SEER 10 | $0.66 | $989 | — |
| SEER 13 | $0.51 | $761 | $228 less |
| SEER 14 | $0.47 | $706 | $282 less |
| SEER 16 | $0.41 | $618 | $371 less |
| SEER 18 | $0.37 | $549 | $439 less |
| SEER 20 | $0.33 | $494 | $494 less |
Every SEER rating, with costs at a high electricity rate too, is in the SEER rating chart.
Window units, portable ACs and mini-splits
Room units are rated in watts. Typical draw while the compressor is running, and the cost at 18.31¢/kWh:
| Unit | Typical draw | Per hour | Per 8-hour day |
|---|---|---|---|
| Small window AC (5,000–6,000 Btu) | 500 W | $0.09 | $0.73 |
| Medium window AC (8,000–10,000 Btu) | 800 W | $0.15 | $1.17 |
| Large window AC (12,000–15,000 Btu) | 1,200 W | $0.22 | $1.76 |
| Portable AC (10,000–14,000 Btu) | 1,200 W | $0.22 | $1.76 |
| Ductless mini-split, one zone (12,000 Btu, ~20 SEER) | 600 W | $0.11 | $0.88 |
Check the label on your unit for its actual wattage; multiply by hours and your rate the same way.
Cost by state
Residential electricity in Hawaii costs 3.8 times as much as in Louisiana, so the same air conditioner can cost very different amounts to run. Each state's full breakdown, by system size and SEER, is on its own page.
Most expensive to run AC
| State | Rate | 3-ton per hour |
|---|---|---|
| Hawaii | 48.00¢ | $1.23 |
| California | 33.61¢ | $0.86 |
| Maine | 32.41¢ | $0.83 |
| Massachusetts | 30.49¢ | $0.78 |
| New York | 29.90¢ | $0.77 |
| Alaska | 28.83¢ | $0.74 |
| Rhode Island | 28.29¢ | $0.73 |
| New Hampshire | 26.60¢ | $0.68 |
| District of Columbia | 25.21¢ | $0.65 |
| New Jersey | 25.19¢ | $0.65 |
See all 50 states and DC →|Costs in the Caribbean →
What makes your AC cost more (or less)
- Your electricity rate. The biggest factor, and the one most people never check. It's on your bill.
- Climate and hours of use. A home on the Gulf Coast can run its AC 3,000 hours a year; one in New England, under 1,000.
- System efficiency. A SEER 10 system uses 40% more electricity than a SEER 14 for the same cooling.
- Size. An oversized system cycles on and off and dehumidifies poorly; an undersized one runs constantly. See the sizing calculator.
- Maintenance. A clogged filter or dirty coil makes the system work harder. See the $10 air filter fix.
- Thermostat habits. Raising the setting when you're out is the cheapest saving there is. See the $0 thermostat strategy.
Frequently asked questions
How much does it cost to run central air per hour?
About $0.47 an hour for a 3-ton central air conditioner rated SEER 14 at the U.S. average residential rate of 18.31¢/kWh (July 2026). The system draws about 2.57 kW. In Hawaii (48.00¢/kWh) the same hour costs $1.23; in Louisiana (12.72¢/kWh), $0.33.
How much does it cost to run AC for a month?
Running 8 hours a day for 30 days, a 3-ton SEER 14 system uses about 617 kWh, which costs about $113 at the U.S. average rate. Running it 12 hours a day costs about $169.
How many kWh does an air conditioner use?
A central AC uses roughly tons × 12 ÷ SEER kilowatt-hours per hour of running. A 3-ton SEER 14 system uses about 2.57 kWh an hour; a 2-ton about 1.71; a 5-ton about 4.29. An older SEER 10 system uses 40% more electricity than a SEER 14 for the same cooling.
Is it cheaper to leave the AC on all day?
Usually not. The Department of Energy says setting the thermostat 7–10°F higher for 8 hours a day can cut cooling costs by up to 10% a year. The system has to remove the heat that built up, but a warmer house gains heat more slowly, so the total energy used is lower.
Sources and method
- Electricity rates: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A (average residential price, July 2026).
- Thermostat savings: U.S. Department of Energy, Energy Saver.
- Power draw is estimated from the SEER rating, which describes average seasonal efficiency, so actual draw is higher on the hottest afternoons and lower on mild days. Cooling hours by state are our climate-based estimate.
Download the data: residential electricity rates by state (CSV). Free to reuse with a link back to this page.
Work out your own cost
Enter your system's SEER, size, hours and electricity rate to see what you pay now and what an upgrade would save.
Open the SEER savings calculator