How much does it cost to run an evaporative cooler?
An evaporative cooler costs about 2.7¢ per hour, 22¢ a day, $6.57 a month and $33 a year at typical use (8 hours a day for 5 months a year) and the U.S. average rate of 17.99¢/kWh. Evaporative coolers only run a fan and small water pump, so they use 75-90% less electricity than air conditioners, but they work well only in dry climates with humidity below about 40%.
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Cost by setting
| Setting | Watts | Per hour | Per day | Per month | Per year |
|---|---|---|---|---|---|
| Portable | 150 | 2.7¢ | 22¢ | $6.57 | $33 |
| Window unit | 450 | 8.1¢ | 65¢ | $19.71 | $99 |
| Whole-house roof unit | 900 | 16¢ | $1.30 | $39.43 | $197 |
At 8 hours a day for 5 months a year and 17.99¢/kWh.
Cost by hours of use
| Hours per day | kWh/day | Per day | Per month | Per year (all year) |
|---|---|---|---|---|
| 1 hour | 0.15 | 2.7¢ | $0.82 | $10 |
| 2 hours | 0.30 | 5.4¢ | $1.64 | $20 |
| 4 hours | 0.60 | 11¢ | $3.29 | $39 |
| 8 hours | 1.20 | 22¢ | $6.57 | $79 |
| 12 hours | 1.80 | 32¢ | $9.86 | $118 |
| 24 hours | 3.60 | 65¢ | $19.71 | $237 |
Cost to run an evaporative cooler in every state
The same evaporative cooler costs $22 a year in North Dakota and $79 in Hawaii, at each state's average residential rate (12 months ending July 2026).
| State | Rate | Per hour | Per month | Per year |
|---|---|---|---|---|
| North Dakota | 12.32¢ | 1.8¢ | $4.50 | $22 |
| Idaho | 12.65¢ | 1.9¢ | $4.62 | $23 |
| Nebraska | 12.86¢ | 1.9¢ | $4.70 | $23 |
| Louisiana | 12.99¢ | 1.9¢ | $4.74 | $24 |
| Utah | 13.32¢ | 2.0¢ | $4.87 | $24 |
| Nevada | 13.36¢ | 2.0¢ | $4.88 | $24 |
| Arkansas | 13.43¢ | 2.0¢ | $4.91 | $25 |
| Tennessee | 13.56¢ | 2.0¢ | $4.95 | $25 |
| Oklahoma | 13.70¢ | 2.1¢ | $5.00 | $25 |
| Montana | 13.84¢ | 2.1¢ | $5.06 | $25 |
| Kentucky | 13.92¢ | 2.1¢ | $5.08 | $25 |
| Missouri | 13.95¢ | 2.1¢ | $5.10 | $25 |
| Wyoming | 14.01¢ | 2.1¢ | $5.12 | $26 |
| Washington | 14.12¢ | 2.1¢ | $5.16 | $26 |
| Iowa | 14.13¢ | 2.1¢ | $5.16 | $26 |
| South Dakota | 14.20¢ | 2.1¢ | $5.19 | $26 |
| Mississippi | 14.77¢ | 2.2¢ | $5.39 | $27 |
| North Carolina | 14.77¢ | 2.2¢ | $5.39 | $27 |
| Kansas | 15.09¢ | 2.3¢ | $5.51 | $28 |
| Georgia | 15.12¢ | 2.3¢ | $5.52 | $28 |
| New Mexico | 15.32¢ | 2.3¢ | $5.60 | $28 |
| Florida | 15.39¢ | 2.3¢ | $5.62 | $28 |
| Arizona | 15.40¢ | 2.3¢ | $5.62 | $28 |
| West Virginia | 15.48¢ | 2.3¢ | $5.65 | $28 |
| Oregon | 15.50¢ | 2.3¢ | $5.66 | $28 |
| South Carolina | 15.64¢ | 2.3¢ | $5.71 | $29 |
| Texas | 15.96¢ | 2.4¢ | $5.83 | $29 |
| Minnesota | 16.22¢ | 2.4¢ | $5.92 | $30 |
| Alabama | 16.44¢ | 2.5¢ | $6.00 | $30 |
| Virginia | 16.48¢ | 2.5¢ | $6.02 | $30 |
| Colorado | 16.58¢ | 2.5¢ | $6.06 | $30 |
| Indiana | 16.94¢ | 2.5¢ | $6.19 | $31 |
| Delaware | 17.79¢ | 2.7¢ | $6.50 | $32 |
| Ohio | 18.25¢ | 2.7¢ | $6.67 | $33 |
| Wisconsin | 18.74¢ | 2.8¢ | $6.84 | $34 |
| Illinois | 18.79¢ | 2.8¢ | $6.86 | $34 |
| Pennsylvania | 20.70¢ | 3.1¢ | $7.56 | $38 |
| Maryland | 21.03¢ | 3.2¢ | $7.68 | $38 |
| Michigan | 21.05¢ | 3.2¢ | $7.69 | $38 |
| New Jersey | 23.78¢ | 3.6¢ | $8.69 | $43 |
| Vermont | 23.80¢ | 3.6¢ | $8.69 | $43 |
| District of Columbia | 24.20¢ | 3.6¢ | $8.84 | $44 |
| New Hampshire | 26.67¢ | 4.0¢ | $9.74 | $49 |
| Alaska | 26.85¢ | 4.0¢ | $9.81 | $49 |
| Connecticut | 27.99¢ | 4.2¢ | $10.22 | $51 |
| New York | 28.39¢ | 4.3¢ | $10.37 | $52 |
| Rhode Island | 29.27¢ | 4.4¢ | $10.69 | $53 |
| Maine | 29.31¢ | 4.4¢ | $10.71 | $54 |
| Massachusetts | 30.43¢ | 4.6¢ | $11.11 | $56 |
| California | 32.99¢ | 4.9¢ | $12.05 | $60 |
| Hawaii | 43.51¢ | 6.5¢ | $15.89 | $79 |
How to cut the cost
- Use it only in dry climates or dry hours; above about 50% humidity it adds moisture rather than cooling much.
- Open a window or door partway on the opposite side of the room to let humid air escape.
- Replace or clean pads every season; clogged pads cut cooling and make the fan run longer.
- Use the lower fan speed overnight; power use drops by about half.
Cheaper ways to get the job done
Better choice in humid climates where evaporative cooling does not work.
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Compare with similar appliances
| Appliance | Watts | Typical use | Per month | Per year |
|---|---|---|---|---|
| Evaporative cooler | 150 | 8 hours a day for 5 months a year | $6.57 | $33 |
| Personal air cooler | 10 | 8 hours a day for 5 months a year | $0.44 | $2 |
| Portable air conditioner | 1,100 | 8 hours a day for 4 months a year | $33.82 | $135 |
| Box fan | 75 | 8 hours a day for 5 months a year | $3.29 | $16 |
| Misting fan | 100 | 4 hours a day, 4 days a week for 5 months a year | $1.25 | $6 |
| Window air conditioner | 700 | 8 hours a day for 4 months a year | $18.49 | $74 |
| Mini split air conditioner | 900 | 10 hours a day for 4 months a year | $27.49 | $110 |
Head-to-head comparisons
Frequently asked questions
How much does it cost to run an evaporative cooler per hour?
An evaporative cooler drawing 150 watts uses 0.15 kWh per hour. At the U.S. average of 17.99¢/kWh that's 2.7¢ per hour. In North Dakota (12.32¢) it's 1.8¢. In Hawaii (43.51¢) it's 6.5¢.
How much does it cost to run an evaporative cooler per month?
At typical use (8 hours a day for 5 months a year), an evaporative cooler costs about $6.57 a month while in use and $33 a year over the 5 months it's typically used, at the U.S. average rate. Enter your ZIP in the calculator above for your utility's rate.
How many watts does an evaporative cooler use?
Most evaporative coolers use 60 to 1,200 watts, depending on the setting (portable 150 W, window unit 450 W, whole-house roof unit 900 W). Check the label on the back or bottom for your model's exact rating.
How many kWh does an evaporative cooler use?
About 1.20 kWh a day and 183 kWh a year at typical use (8 hours a day for 5 months a year).
Does an evaporative cooler use a lot of electricity?
No. At about 183 kWh a year it's a small share (1.7%) of the average U.S. home's 10,492 kWh.
Is it cheaper to run an evaporative cooler or a personal air cooler?
At typical use, an evaporative cooler costs about $33 a year versus $2 for a personal air cooler. So the personal air cooler is cheaper by about $31 a year. Use the comparison table above to compare them at your own settings.
How can I lower the cost of running an evaporative cooler?
- Use it only in dry climates or dry hours; above about 50% humidity it adds moisture rather than cooling much.
- Open a window or door partway on the opposite side of the room to let humid air escape.
- Replace or clean pads every season; clogged pads cut cooling and make the fan run longer.
Rates updated 2026-10-21: EIA data through July 2026. Typical wattage and usage reviewed against DOE, ENERGY STAR and manufacturer specs. Methodology.