How much does it cost to run a window fan?
A window fan costs about 1.1¢ per hour, 8.6¢ a day, $2.63 a month and $13 a year at typical use (8 hours a day for 5 months a year) and the U.S. average rate of 17.99¢/kWh. Twin and reversible window fans draw about 35-70 W and are most useful for pulling cool night air through the house.
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Cost by setting
| Setting | Watts | Per hour | Per day | Per month | Per year |
|---|---|---|---|---|---|
| Low | 35 | 0.6¢ | 5.0¢ | $1.53 | $8 |
| High | 60 | 1.1¢ | 8.6¢ | $2.63 | $13 |
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 | 0.06 | 1.1¢ | $0.33 | $4 |
| 2 hours | 0.12 | 2.2¢ | $0.66 | $8 |
| 4 hours | 0.24 | 4.3¢ | $1.31 | $16 |
| 8 hours | 0.48 | 8.6¢ | $2.63 | $32 |
| 12 hours | 0.72 | 13¢ | $3.94 | $47 |
| 24 hours | 1.44 | 26¢ | $7.89 | $95 |
Cost to run a window fan in every state
The same window fan costs $9 a year in North Dakota and $32 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¢ | 0.7¢ | $1.80 | $9 |
| Idaho | 12.65¢ | 0.8¢ | $1.85 | $9 |
| Nebraska | 12.86¢ | 0.8¢ | $1.88 | $9 |
| Louisiana | 12.99¢ | 0.8¢ | $1.90 | $9 |
| Utah | 13.32¢ | 0.8¢ | $1.95 | $10 |
| Nevada | 13.36¢ | 0.8¢ | $1.95 | $10 |
| Arkansas | 13.43¢ | 0.8¢ | $1.96 | $10 |
| Tennessee | 13.56¢ | 0.8¢ | $1.98 | $10 |
| Oklahoma | 13.70¢ | 0.8¢ | $2.00 | $10 |
| Montana | 13.84¢ | 0.8¢ | $2.02 | $10 |
| Kentucky | 13.92¢ | 0.8¢ | $2.03 | $10 |
| Missouri | 13.95¢ | 0.8¢ | $2.04 | $10 |
| Wyoming | 14.01¢ | 0.8¢ | $2.05 | $10 |
| Washington | 14.12¢ | 0.8¢ | $2.06 | $10 |
| Iowa | 14.13¢ | 0.8¢ | $2.06 | $10 |
| South Dakota | 14.20¢ | 0.9¢ | $2.07 | $10 |
| Mississippi | 14.77¢ | 0.9¢ | $2.16 | $11 |
| North Carolina | 14.77¢ | 0.9¢ | $2.16 | $11 |
| Kansas | 15.09¢ | 0.9¢ | $2.20 | $11 |
| Georgia | 15.12¢ | 0.9¢ | $2.21 | $11 |
| New Mexico | 15.32¢ | 0.9¢ | $2.24 | $11 |
| Florida | 15.39¢ | 0.9¢ | $2.25 | $11 |
| Arizona | 15.40¢ | 0.9¢ | $2.25 | $11 |
| West Virginia | 15.48¢ | 0.9¢ | $2.26 | $11 |
| Oregon | 15.50¢ | 0.9¢ | $2.26 | $11 |
| South Carolina | 15.64¢ | 0.9¢ | $2.29 | $11 |
| Texas | 15.96¢ | 1.0¢ | $2.33 | $12 |
| Minnesota | 16.22¢ | 1.0¢ | $2.37 | $12 |
| Alabama | 16.44¢ | 1.0¢ | $2.40 | $12 |
| Virginia | 16.48¢ | 1.0¢ | $2.41 | $12 |
| Colorado | 16.58¢ | 1.0¢ | $2.42 | $12 |
| Indiana | 16.94¢ | 1.0¢ | $2.47 | $12 |
| Delaware | 17.79¢ | 1.1¢ | $2.60 | $13 |
| Ohio | 18.25¢ | 1.1¢ | $2.67 | $13 |
| Wisconsin | 18.74¢ | 1.1¢ | $2.74 | $14 |
| Illinois | 18.79¢ | 1.1¢ | $2.75 | $14 |
| Pennsylvania | 20.70¢ | 1.2¢ | $3.02 | $15 |
| Maryland | 21.03¢ | 1.3¢ | $3.07 | $15 |
| Michigan | 21.05¢ | 1.3¢ | $3.08 | $15 |
| New Jersey | 23.78¢ | 1.4¢ | $3.47 | $17 |
| Vermont | 23.80¢ | 1.4¢ | $3.48 | $17 |
| District of Columbia | 24.20¢ | 1.5¢ | $3.54 | $18 |
| New Hampshire | 26.67¢ | 1.6¢ | $3.90 | $19 |
| Alaska | 26.85¢ | 1.6¢ | $3.92 | $20 |
| Connecticut | 27.99¢ | 1.7¢ | $4.09 | $20 |
| New York | 28.39¢ | 1.7¢ | $4.15 | $21 |
| Rhode Island | 29.27¢ | 1.8¢ | $4.28 | $21 |
| Maine | 29.31¢ | 1.8¢ | $4.28 | $21 |
| Massachusetts | 30.43¢ | 1.8¢ | $4.45 | $22 |
| California | 32.99¢ | 2.0¢ | $4.82 | $24 |
| Hawaii | 43.51¢ | 2.6¢ | $6.36 | $32 |
How to cut the cost
- Run it in exhaust mode on the warm side of the house with a window open on the cool, shaded side.
- Use it in the evening and overnight when outdoor air is below indoor temperature, then close windows and blinds by mid-morning.
- Use the built-in thermostat (on some Bionaire models) so it stops when the room cools.
- Seal side gaps with the expansion panels so air is pulled through the house, not around the fan.
Cheaper ways to get the job done
Flushes heat from the entire house in minutes and can replace hours of AC.
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Compare with similar appliances
| Appliance | Watts | Typical use | Per month | Per year |
|---|---|---|---|---|
| Window fan | 60 | 8 hours a day for 5 months a year | $2.63 | $13 |
| Box fan | 75 | 8 hours a day for 5 months a year | $3.29 | $16 |
| Whole house fan | 300 | 5 hours a day for 5 months a year | $8.21 | $41 |
| Attic fan | 300 | 8 hours a day for 5 months a year | $9.20 | $46 |
| Window air conditioner | 700 | 8 hours a day for 4 months a year | $18.49 | $74 |
| Air circulator fan | 60 | 8 hours a day for 5 months a year | $2.63 | $13 |
| Radon fan | 70 | 24 hours a day | $9.20 | $110 |
Head-to-head comparisons
Frequently asked questions
How much does it cost to run a window fan per hour?
A window fan drawing 60 watts uses 0.06 kWh per hour. At the U.S. average of 17.99¢/kWh that's 1.1¢ per hour. In North Dakota (12.32¢) it's 0.7¢. In Hawaii (43.51¢) it's 2.6¢.
How much does it cost to run a window fan per month?
At typical use (8 hours a day for 5 months a year), a window fan costs about $2.63 a month while in use and $13 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 a window fan use?
Most window fans use 30 to 110 watts, depending on the setting (low 35 W, high 60 W). Check the label on the back or bottom for your model's exact rating.
How many kWh does a window fan use?
About 0.48 kWh a day and 73 kWh a year at typical use (8 hours a day for 5 months a year).
Does a window fan use a lot of electricity?
No. At about 73 kWh a year it's a small share (0.7%) of the average U.S. home's 10,492 kWh.
Is it cheaper to run a window fan or a box fan?
At typical use, a window fan costs about $13 a year versus $16 for a box fan. So the window fan is cheaper by about $3 a year. Use the comparison table above to compare them at your own settings.
How can I lower the cost of running a window fan?
- Run it in exhaust mode on the warm side of the house with a window open on the cool, shaded side.
- Use it in the evening and overnight when outdoor air is below indoor temperature, then close windows and blinds by mid-morning.
- Use the built-in thermostat (on some Bionaire models) so it stops when the room cools.
Rates updated 2026-10-21: EIA data through July 2026. Typical wattage and usage reviewed against DOE, ENERGY STAR and manufacturer specs. Methodology.