How Much Does It Cost to Run a Whole House Fan?
A typical Whole House Fan uses 500W and runs about 6 hours/day. At the national average rate of 16.72¢/kWh, that costs approximately $15.05/month.
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What Affects the Cost of Running a Whole House Fan
A Whole House Fan Uses 80-90% Less Electricity Than AC
A whole house fan draws 200-700W compared to 3,000-5,000W for central AC. In climates where evening temperatures drop below 75-80F, running a whole house fan from dusk to dawn can eliminate the need for AC on many nights, cutting cooling costs by $50-100/month during summer. The fan pulls cool outside air through open windows and pushes hot attic air out through the roof vents, cooling the entire home in 10-15 minutes.
Climate Determines Whether This Appliance Makes Sense
Whole house fans work best in climates with significant day-night temperature swings: hot days but cool evenings (below 75F). This includes much of California, the Mountain West, the Pacific Northwest, and parts of the Midwest. In humid climates like the Southeast, where nighttime temperatures stay above 80F with high humidity, a whole house fan brings in warm, muggy air and is largely ineffective. Know your climate before investing.
Whole House Fan vs. Alternatives
How the monthly cost of a Whole House Fan compares to other options:
| Alternative | Est. Monthly Cost | Notes |
|---|---|---|
| Whole House Fan (this page) | $15.05 | At national average rate, 6hrs/day |
| Central AC | ~$40-80 | Cools in any weather but costs 5-10x more to operate per hour. |
| Ceiling fans (multiple) | ~$10-20 | Cheaper per unit but do not actively exchange indoor and outdoor air. |
| Attic fan (attic only) | ~$3-8 | Only cools the attic, not the living space. Reduces AC load but does not replace it. |
| Window fans (exhaust) | ~$3-6 | Similar concept on a smaller scale. Good for apartments where whole house fans cannot be installed. |
Whole House Fan Cost by State
What a Whole House Fan costs to run at 500W for 6 hours/day in every state:
| State | Rate | Monthly Cost | Yearly Cost |
|---|---|---|---|
| Alabama | 14.82¢ | $13.34 | $160.06 |
| Alaska | 25.34¢ | $22.81 | $273.67 |
| Arizona | 13.81¢ | $12.43 | $149.15 |
| Arkansas | 12.63¢ | $11.37 | $136.4 |
| California | 31.41¢ | $28.27 | $339.23 |
| Colorado | 15.24¢ | $13.72 | $164.59 |
| Connecticut | 29.35¢ | $26.42 | $316.98 |
| Delaware | 15.24¢ | $13.72 | $164.59 |
| District of Columbia | 15.87¢ | $14.28 | $171.4 |
| Florida | 15.63¢ | $14.07 | $168.8 |
| Georgia | 14.12¢ | $12.71 | $152.5 |
| Hawaii | 43.21¢ | $38.89 | $466.67 |
| Idaho | 10.87¢ | $9.78 | $117.4 |
| Illinois | 16.37¢ | $14.73 | $176.8 |
| Indiana | 15.12¢ | $13.61 | $163.3 |
| Iowa | 14.23¢ | $12.81 | $153.68 |
| Kansas | 14.98¢ | $13.48 | $161.78 |
| Kentucky | 12.87¢ | $11.58 | $139 |
| Louisiana | 11.98¢ | $10.78 | $129.38 |
| Maine | 22.87¢ | $20.58 | $247 |
| Maryland | 16.12¢ | $14.51 | $174.1 |
| Massachusetts | 28.76¢ | $25.88 | $310.61 |
| Michigan | 18.76¢ | $16.88 | $202.61 |
| Minnesota | 15.34¢ | $13.81 | $165.67 |
| Mississippi | 13.76¢ | $12.38 | $148.61 |
| Missouri | 13.12¢ | $11.81 | $141.7 |
| Montana | 12.45¢ | $11.21 | $134.46 |
| Nebraska | 11.98¢ | $10.78 | $129.38 |
| Nevada | 15.03¢ | $13.53 | $162.32 |
| New Hampshire | 25.34¢ | $22.81 | $273.67 |
| New Jersey | 18.76¢ | $16.88 | $202.61 |
| New Mexico | 14.87¢ | $13.38 | $160.6 |
| New York | 22.87¢ | $20.58 | $247 |
| North Carolina | 13.98¢ | $12.58 | $150.98 |
| North Dakota | 11.87¢ | $10.68 | $128.2 |
| Ohio | 15.34¢ | $13.81 | $165.67 |
| Oklahoma | 11.98¢ | $10.78 | $129.38 |
| Oregon | 13.12¢ | $11.81 | $141.7 |
| Pennsylvania | 16.87¢ | $15.18 | $182.2 |
| Rhode Island | 27.12¢ | $24.41 | $292.9 |
| South Carolina | 14.98¢ | $13.48 | $161.78 |
| South Dakota | 13.76¢ | $12.38 | $148.61 |
| Tennessee | 12.87¢ | $11.58 | $139 |
| Texas | 14.98¢ | $13.48 | $161.78 |
| Utah | 10.87¢ | $9.78 | $117.4 |
| Vermont | 21.34¢ | $19.21 | $230.47 |
| Virginia | 15.34¢ | $13.81 | $165.67 |
| Washington | 10.76¢ | $9.68 | $116.21 |
| West Virginia | 13.12¢ | $11.81 | $141.7 |
| Wisconsin | 16.98¢ | $15.28 | $183.38 |
| Wyoming | 11.23¢ | $10.11 | $121.28 |
Energy-Saving Tips for Your Whole House Fan
- Open windows before turning on; the fan needs intake air
- Run in the evening when outdoor air is cooler than indoor
- Can reduce AC usage significantly in dry climates
- Close the fan cover in winter to prevent heat loss through the attic
Frequently Asked Questions
In dry climates with cool evenings, a whole house fan can replace AC on many nights and significantly reduce AC usage during the day. In Denver, Sacramento, or Portland, homeowners report cutting AC use by 50-90%. In humid climates like Houston or Miami, a whole house fan is not a substitute for AC because evening air is too warm and humid to provide comfort.
Yes, always. A whole house fan pulls air from inside the house and pushes it into the attic. If windows are not open, the fan creates strong negative pressure that can backdraft gas appliances (water heaters, furnaces) and pull combustion gases into the living space. Open windows on the side of the house facing the breeze for best results. The rule of thumb is to open windows with a total area of at least 2-3 square feet per 1,000 CFM of fan capacity.
A typical 500W whole house fan running for 6 hours costs about $0.50 per night at the national average rate. Over a 4-month cooling season (120 nights), that is roughly $60 total. Compare that to central AC at $40-80 per month, and the savings are substantial. Even accounting for the installation cost ($1,000-2,500), a whole house fan typically pays for itself in 1-2 cooling seasons.
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Electric Baseboard Heater
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Infrared Heater
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Dehumidifier
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Electricity cost estimates are based on typical wattage and average residential rates from the U.S. Energy Information Administration. Your actual costs may vary based on your appliance's specific wattage, usage patterns, and your utility's rate structure. See our full disclaimer.