How much does it cost to run a central air conditioner?
Short answer: A central air conditioner drawing 3,500 watts costs about $0.64 per hour at the U.S. average residential price of 18.31¢ per kWh. Used 8 hours a day, 30 days a month, that is about $153.80 per month and $1,846 per year. In Louisiana, the cheapest state, the same use costs $106.85 a month; in Hawaii, the most expensive, $403.20.
Central air conditioner cost calculator
Hours per day the outdoor unit is actually running, not hours the thermostat is set to cool. Eight hours is typical for a hot summer day.
Energy used: 840.0 kWh per month. Default price is the U.S. residential average; pick your state or type the price from your own bill.
Central air is the largest summer electricity load in most American homes. A common 3-ton system draws about 3,500 watts while the compressor and blower are running, and smaller or larger systems scale roughly with their tonnage.
Cost by size and setting
Costs below use the U.S. average price and 8 hours a day, 30 days a month.
| Type | Power | Per hour | Per month |
|---|---|---|---|
| 2-ton system | 2,400 W | $0.44 | $105.47 |
| 3-ton system | 3,500 W | $0.64 | $153.80 |
| 5-ton system | 5,800 W | $1.06 | $254.88 |
What decides how much your system uses
Three things: the size of the system in tons, its efficiency rating (SEER2), and how many hours a day it has to run. Size and efficiency are fixed once the equipment is installed. Run time is where the bill is decided, and it depends on the weather, your thermostat setting, and how well the house holds its cool.
As a rule of thumb, each ton of cooling draws roughly 1,000 to 1,200 watts on a mid-efficiency system. Newer high-SEER2 and variable-speed systems draw noticeably less for the same cooling, especially on milder days when they can run at part speed.
Why two similar houses get very different bills
Leaky ductwork in a hot attic can waste a fifth or more of the cooling before it reaches a room. Thin attic insulation, unshaded west-facing windows and a thermostat set a few degrees lower all add hours of run time. This is why a neighbor with the same size home can pay half as much.
How to lower the cost
- Raise the set point. The Department of Energy suggests 78°F when you are home and higher when you are away.
- Replace the air filter on schedule; restricted airflow lengthens every cooling cycle.
- Use ceiling fans so you feel comfortable at a higher thermostat setting.
- Have the ducts checked for leaks, and keep the outdoor unit clear of leaves and shrubs.
Cost to run a central air conditioner in every state
Based on 3,500 watts for 8 hours a day, 30 days a month, at each state's average residential electricity price for July 2026.
| State | Price per kWh | Per hour | Per month | Per year |
|---|---|---|---|---|
| Alabama | 16.40¢ | $0.57 | $137.76 | $1,653 |
| Alaska | 28.83¢ | $1.01 | $242.17 | $2,906 |
| Arizona | 15.38¢ | $0.54 | $129.19 | $1,550 |
| Arkansas | 14.33¢ | $0.50 | $120.37 | $1,444 |
| California | 33.61¢ | $1.18 | $282.32 | $3,388 |
| Colorado | 17.00¢ | $0.60 | $142.80 | $1,714 |
| Connecticut | 24.16¢ | $0.85 | $202.94 | $2,435 |
| Delaware | 18.48¢ | $0.65 | $155.23 | $1,863 |
| District of Columbia | 25.21¢ | $0.88 | $211.76 | $2,541 |
| Florida | 15.03¢ | $0.53 | $126.25 | $1,515 |
| Georgia | 16.27¢ | $0.57 | $136.67 | $1,640 |
| Hawaii | 48.00¢ | $1.68 | $403.20 | $4,838 |
| Idaho | 13.73¢ | $0.48 | $115.33 | $1,384 |
| Illinois | 19.22¢ | $0.67 | $161.45 | $1,937 |
| Indiana | 16.73¢ | $0.59 | $140.53 | $1,686 |
| Iowa | 15.99¢ | $0.56 | $134.32 | $1,612 |
| Kansas | 15.27¢ | $0.53 | $128.27 | $1,539 |
| Kentucky | 13.81¢ | $0.48 | $116.00 | $1,392 |
| Louisiana | 12.72¢ | $0.45 | $106.85 | $1,282 |
| Maine | 32.41¢ | $1.13 | $272.24 | $3,267 |
| Maryland | 21.41¢ | $0.75 | $179.84 | $2,158 |
| Massachusetts | 30.49¢ | $1.07 | $256.12 | $3,073 |
| Michigan | 23.05¢ | $0.81 | $193.62 | $2,323 |
| Minnesota | 17.45¢ | $0.61 | $146.58 | $1,759 |
| Mississippi | 14.54¢ | $0.51 | $122.14 | $1,466 |
| Missouri | 16.09¢ | $0.56 | $135.16 | $1,622 |
| Montana | 14.99¢ | $0.52 | $125.92 | $1,511 |
| Nebraska | 13.78¢ | $0.48 | $115.75 | $1,389 |
| Nevada | 12.77¢ | $0.45 | $107.27 | $1,287 |
| New Hampshire | 26.60¢ | $0.93 | $223.44 | $2,681 |
| New Jersey | 25.19¢ | $0.88 | $211.60 | $2,539 |
| New Mexico | 16.09¢ | $0.56 | $135.16 | $1,622 |
| New York | 29.90¢ | $1.05 | $251.16 | $3,014 |
| North Carolina | 15.16¢ | $0.53 | $127.34 | $1,528 |
| North Dakota | 13.41¢ | $0.47 | $112.64 | $1,352 |
| Ohio | 19.45¢ | $0.68 | $163.38 | $1,961 |
| Oklahoma | 14.35¢ | $0.50 | $120.54 | $1,446 |
| Oregon | 15.97¢ | $0.56 | $134.15 | $1,610 |
| Pennsylvania | 21.72¢ | $0.76 | $182.45 | $2,189 |
| Rhode Island | 28.29¢ | $0.99 | $237.64 | $2,852 |
| South Carolina | 15.47¢ | $0.54 | $129.95 | $1,559 |
| South Dakota | 15.37¢ | $0.54 | $129.11 | $1,549 |
| Tennessee | 13.71¢ | $0.48 | $115.16 | $1,382 |
| Texas | 15.88¢ | $0.56 | $133.39 | $1,601 |
| Utah | 13.12¢ | $0.46 | $110.21 | $1,322 |
| Vermont | 23.75¢ | $0.83 | $199.50 | $2,394 |
| Virginia | 17.55¢ | $0.61 | $147.42 | $1,769 |
| Washington | 14.71¢ | $0.51 | $123.56 | $1,483 |
| West Virginia | 15.78¢ | $0.55 | $132.55 | $1,591 |
| Wisconsin | 19.06¢ | $0.67 | $160.10 | $1,921 |
| Wyoming | 14.36¢ | $0.50 | $120.62 | $1,447 |
Frequently asked questions
How much does central air cost per month?
A 3,500-watt system running 8 hours a day uses about 840 kWh in a 30-day month. At the U.S. average price that is roughly $153.80. See the state table for your local figure.
How many watts does a 3-ton air conditioner use?
About 3,000 to 4,000 watts while running, depending on its efficiency rating and the outdoor temperature. The calculator uses 3,500 watts as a middle value.
Does a smart thermostat really save money?
It saves money only by reducing run time, mostly by letting the house warm up when nobody is home. If you already adjust the thermostat by hand, the savings are small.