How much does a whole-house fan cost to run?

$17 a month while in use, May to September

A day of use
$0.54
An hour of running
$0.09
A year (season only)
$83.34

495 W, 6 hours a day in the evening, May to September, at the US average of 18.3¢ per kWh (EIA, June 2026). How we calculate this

Change the watts, hours or rate
I know the appliance's

What it costs at other usage levels

Whole-house fan at 495 W and 18.3¢ per kWh, May to September
UseA dayA month in useA year
1 hour a day$0.09$2.76$13.89
2 hours a day$0.18$5.52$27.78
4 hours a day$0.36$11.05$55.56
6 hours a day typical$0.54$16.57$83.34
8 hours a day$0.73$22.09$111.12
24 hours a day$2.18$66.27$333.36
Monthly cost of a whole-house fan by usage at the US average rate1 hour a day: $2.76; 2 hours a day: $5.52; 4 hours a day: $11.05; 6 hours a day: $16.57; 8 hours a day: $22.09; 24 hours a day: $66.271 hour a day$2.762 hours a day$5.524 hours a day$11.056 hours a day$16.578 hours a day$22.0924 hours a day$66.27

Models range from 240 W to 750 W (Virginia Cooperative Extension). We use 495 W, the middle of that range.

Ways to spend less

  • Run it only when the outdoor air is cooler than indoors, usually evening and early morning.
  • Open windows before switching it on so it pulls in outside air instead of straining.
  • Run it one hour less a day. Saves about $2.76 a month in season.

What a whole-house fan costs to run in every state

Same usage, each state's latest EIA residential rate, cheapest first
RankStateRateA month in useA year
1Nevada13.1¢$11.84$59.57
2Nebraska13.3¢$11.97$60.21
3Utah13.4¢$12.08$60.75
4Louisiana13.5¢$12.19$61.30
5Tennessee14.1¢$12.71$63.94
6Arkansas14.1¢$12.76$64.16
7North Dakota14.1¢$12.76$64.16
8Kentucky14.3¢$12.88$64.80
9Oklahoma14.3¢$12.95$65.12
10Idaho14.4¢$12.98$65.30
11North Carolina14.7¢$13.32$66.98
12Mississippi14.9¢$13.44$67.62
13Washington14.9¢$13.47$67.75
14New Mexico15.1¢$13.60$68.43
15Florida15.1¢$13.64$68.62
16Montana15.1¢$13.68$68.80
17Arizona15.2¢$13.71$68.98
18Wyoming15.2¢$13.77$69.25
19South Dakota15.4¢$13.88$69.80
20West Virginia15.5¢$13.96$70.21
21South Carolina15.6¢$14.05$70.66
22Kansas15.7¢$14.19$71.39
23Iowa15.9¢$14.39$72.39
24Texas15.9¢$14.40$72.43
25Missouri16.2¢$14.65$73.71
26Oregon16.3¢$14.74$74.16
27Georgia16.4¢$14.78$74.34
28Alabama16.4¢$14.82$74.52
29Colorado17.1¢$15.47$77.84
30Virginia17.2¢$15.56$78.25
31Indiana17.5¢$15.82$79.57
32Minnesota17.5¢$15.83$79.61
33Ohio19.2¢$17.34$87.20
34Delaware19.3¢$17.43$87.66
35Wisconsin19.6¢$17.67$88.88
36Illinois19.9¢$17.97$90.38
37Pennsylvania21.7¢$19.63$98.74
38Maryland21.8¢$19.73$99.24
39Michigan23.0¢$20.77$104.47
40Connecticut24.3¢$21.97$110.51
41District of Columbia24.4¢$22.03$110.83
42Vermont24.4¢$22.08$111.06
43New Jersey25.0¢$22.54$113.38
44New Hampshire27.0¢$24.40$122.74
45Alaska28.2¢$25.48$128.19
46Rhode Island29.2¢$26.41$132.82
47New York29.5¢$26.64$134.01
48Maine29.6¢$26.73$134.46
49Massachusetts29.6¢$26.75$134.55
50California34.7¢$31.38$157.86
51Hawaii52.7¢$47.63$239.56

Questions

How much does it cost to run a whole-house fan per hour?

About $0.09 an hour. A whole-house fan at 495 W uses 0.495 kWh per hour, and at the US average of 18.3¢ per kWh that comes to $0.09.

How much does a whole-house fan add to your electric bill?

Used 6 hours a day in the evening, May to September, about $16.57 a month while it is in use, or $83.34 a year across the May to September season.

How much does it cost to run a whole-house fan 24 hours a day?

Running nonstop, a whole-house fan would use 11.9 kWh a day and cost $2.18 a day, or $66.27 over an average month.

How many watts does a whole-house fan use?

Models range from 240 W to 750 W (Virginia Cooperative Extension). We use 495 W, the middle of that range. Check the label on yours: cost scales directly with watts, so a 20% lower wattage means a 20% lower bill.

Which state is cheapest to run a whole-house fan in?

Nevada, at 13.1¢ per kWh: $11.84 a month. The most expensive is Hawaii at 52.7¢ per kWh: $47.63 a month. Same appliance, same hours; only the rate differs.

Sources

Usage assumptions (hours a day, season) are ours and listed on the methodology page. Found an error? Tell us.