hvac · 300W typical
Running a attic fan costs about $5.35/month.
That's the typical attic fan at 300W, run 6 hours a day at the US-average rate of 16.5¢/kWh. Change any of those and the number moves — use the calculator below to see yours.
Estimated cost
A attic fan draws full power only while the thermostat/compressor is running — about 3.6 effective hours at 300W across your 6-hour window.
How you use it
Cost shifts with how long it's on.
The same attic fan can cost very different amounts depending on usage patterns. Three common scenarios, at the US-average rate.
summer heat dump
$5.35
per month
thermostat-triggered during hottest part of day
evening cool-down
$3.56
per month
pulls cool evening air into attic and house
shoulder season
$1.78
per month
light use during warm but not hot days
Where you live
$9.69 spread between the cheapest and priciest states.
Same appliance, same hours of use, different zip code — the monthly cost varies this much.
| State | Rate | Monthly | Yearly |
|---|---|---|---|
| Hawaii | 41.2¢ | $13.35 | $162.41 |
| California | 31.4¢ | $10.17 | $123.78 |
| Massachusetts | 30.8¢ | $9.98 | $121.41 |
| Connecticut | 28.7¢ | $9.30 | $113.14 |
| Rhode Island | 27.9¢ | $9.04 | $109.98 |
| New Hampshire | 24.6¢ | $7.97 | $96.97 |
| Alaska | 24.3¢ | $7.87 | $95.79 |
| New York | 22.3¢ | $7.23 | $87.91 |
| Maine | 22.1¢ | $7.16 | $87.12 |
| Vermont | 21.5¢ | $6.97 | $84.75 |
| Michigan | 19.3¢ | $6.25 | $76.08 |
| New Jersey | 19.1¢ | $6.19 | $75.29 |
| Maryland | 18.4¢ | $5.96 | $72.53 |
| Pennsylvania | 18.1¢ | $5.86 | $71.35 |
| District of Columbia | 17.8¢ | $5.77 | $70.17 |
| Wisconsin | 17.4¢ | $5.64 | $68.59 |
| Delaware | 17.2¢ | $5.57 | $67.80 |
| Illinois | 16.9¢ | $5.48 | $66.62 |
| Ohio | 16.6¢ | $5.38 | $65.44 |
| Nevada | 16.3¢ | $5.28 | $64.25 |
| Indiana | 15.8¢ | $5.12 | $62.28 |
| Virginia | 15.7¢ | $5.09 | $61.89 |
| Minnesota | 15.6¢ | $5.05 | $61.50 |
| Colorado | 15.4¢ | $4.99 | $60.71 |
| Alabama | 15.2¢ | $4.92 | $59.92 |
| West Virginia | 15.2¢ | $4.92 | $59.92 |
| Florida | 15.1¢ | $4.89 | $59.52 |
| New Mexico | 14.8¢ | $4.80 | $58.34 |
| Texas | 14.8¢ | $4.80 | $58.34 |
| Arizona | 14.7¢ | $4.76 | $57.95 |
| South Carolina | 14.7¢ | $4.76 | $57.95 |
| Kansas | 14.6¢ | $4.73 | $57.55 |
| Georgia | 14.2¢ | $4.60 | $55.98 |
| Iowa | 14.1¢ | $4.57 | $55.58 |
| North Carolina | 13.9¢ | $4.50 | $54.79 |
| Missouri | 13.6¢ | $4.41 | $53.61 |
| Oregon | 13.4¢ | $4.34 | $52.82 |
| Tennessee | 13.3¢ | $4.31 | $52.43 |
| Kentucky | 13.2¢ | $4.28 | $52.03 |
| Mississippi | 13.1¢ | $4.24 | $51.64 |
| Oklahoma | 13.1¢ | $4.24 | $51.64 |
| South Dakota | 12.7¢ | $4.11 | $50.06 |
| Montana | 12.4¢ | $4.02 | $48.88 |
| Nebraska | 12.2¢ | $3.95 | $48.09 |
| Arkansas | 12.1¢ | $3.92 | $47.70 |
| Washington | 12.1¢ | $3.92 | $47.70 |
| Louisiana | 11.9¢ | $3.86 | $46.91 |
| Wyoming | 11.6¢ | $3.76 | $45.73 |
| North Dakota | 11.5¢ | $3.73 | $45.33 |
| Utah | 11.4¢ | $3.69 | $44.94 |
| Idaho | 11.3¢ | $3.66 | $44.54 |
Efficient vs. inefficient
A $97.56/year difference across the wattage range.
Swapping a high-draw model for an efficient one pays for itself. Here's what that looks like annually at typical usage.
Most efficient
150W
$2.67 per month
$32.52 per year
Typical
300W
$5.35 per month
$65.04 per year
High draw
600W
$10.69 per month
$130.09 per year
When it hits hardest
summer peak
June-September only; often paired with central AC to reduce load.
Ways to cut the cost
- 1
Install a thermostat so fan only runs when attic exceeds 100°F
Cuts runtime 60-70% vs. dawn-to-dusk
- 2
Seal attic floor air leaks before adding a fan — else fan sucks conditioned air up
Poorly sealed attics negate 50%+ of the fan's AC savings
- 3
Consider solar-powered replacement
Eliminates grid draw entirely
Real-world wattages
Pulled from actual spec sheets.
| Brand | Model | Watts |
|---|---|---|
| Broan | 345CS0000 | 340W |
| Cool Attic | CX1500UPS | 300W |
| QuietCool | AFG PRO-2.0 | 275W |
Picks that actually move the needle
Three products worth comparing if you're thinking about upgrading or supplementing what you have.
Some links below are affiliate links. If you buy, we may earn a small commission — it never changes the price you pay, and we only recommend picks we would stand behind.
See also
Related appliances
Sources: www.energy.gov · www.energystar.gov
Last updated: 2026-04-13