WattCostCalc

Cost to Run a 500-watt attic ventilation fan for 24 hours

Running a 500-watt attic ventilation fan for 24 hours uses 12 kWh and costs $2.10 at $0.175/kWh. Do that every day and it adds up to $63.00 a month.

$2.10 for 24 hoursat $0.175/kWh

Calculate your own cost

Hours per day:
$2.10per day
Per hour
$0.0880.5 kWh
Per day
$2.1012 kWh
Per week
$14.7084 kWh
Per month (30 days)
$63.00360 kWh
Per year
$766.504,380 kWh

Formula: watts ÷ 1,000 × hours × rate. Edit any box and every number updates instantly.

People also ask

How much does a 500-watt attic ventilation fan cost per hour?

At $0.175/kWh, it costs $0.088 per hour. The maths: 500 W ÷ 1,000 = 0.5 kWh per hour, × $0.175 = $0.088.

How much does it cost per month?

Used 24 hours a day for 30 days, it costs about $63.00 per month and uses 360 kWh. Change the hours in the calculator above to match how you use it.

How many kWh does it use?

12 kWh per day, 360 kWh per month and 4,380 kWh per year at 24 hours a day. A kWh is one kilowatt (1,000 W) used for one hour. It is the unit on your electricity bill.

How can I lower the cost?

Use the right control settings and ensure the attic has adequate intake vents. Check your bill for the exact rate and enter it above.

Does my electricity rate change the answer?

Yes, a lot. At 10¢ per kWh the monthly cost is $36.00 and at 30¢ it is $108.00. Find your rate on your bill (total cost ÷ kWh used) and type it into the calculator.

Cost by hours of use

Used per dayEnergy per dayCost per dayCost per monthCost per year
1 hour0.5 kWh$0.088$2.63$31.94
2 hours1 kWh$0.175$5.25$63.88
3 hours1.5 kWh$0.263$7.88$95.81
4 hours2 kWh$0.35$10.50$127.75
5 hours2.5 kWh$0.438$13.13$159.69
6 hours3 kWh$0.525$15.75$191.63
7 hours3.5 kWh$0.613$18.38$223.56
8 hours4 kWh$0.70$21.00$255.50
9 hours4.5 kWh$0.788$23.63$287.44
10 hours5 kWh$0.875$26.25$319.38
11 hours5.5 kWh$0.963$28.88$351.31
12 hours6 kWh$1.05$31.50$383.25
13 hours6.5 kWh$1.14$34.13$415.19
14 hours7 kWh$1.23$36.75$447.13
15 hours7.5 kWh$1.31$39.38$479.06
16 hours8 kWh$1.40$42.00$511.00
17 hours8.5 kWh$1.49$44.63$542.94
18 hours9 kWh$1.58$47.25$574.88
19 hours9.5 kWh$1.66$49.88$606.81
20 hours10 kWh$1.75$52.50$638.75
21 hours10.5 kWh$1.84$55.13$670.69
22 hours11 kWh$1.93$57.75$702.63
23 hours11.5 kWh$2.01$60.38$734.56
24 hours12 kWh$2.10$63.00$766.50

How we worked it out

  1. Energy per hour: 500 W ÷ 1,000 = 0.5 kWh
  2. Cost per hour: 0.5 kWh × $0.175 = $0.088
  3. Cost per day: × 24 hours = $2.10
  4. Month and year: × 30 days = $63.00, × 365 days = $766.50

What it costs in different places

Same 500-watt attic ventilation fan, 24 hours a day. Only the local electricity rate changes.

PlaceRate per kWhCost per month
United States$0.175$63.00
California$0.32$115.20
Texas$0.155$55.80
New York$0.25$90.00
Florida$0.155$55.80
Illinois$0.17$61.20
Pennsylvania$0.18$64.80
Ohio$0.17$61.20
Washington$0.115$41.40

About attic ventilation fan running costs

Attic fans use a motor for ventilation. Actual power depends on fan size and whether a thermostat or humidistat controls it.

Typical sizes: 150 W, 300 W, 500 W, 800 W.

How to spend less: Use the right control settings and ensure the attic has adequate intake vents.

What this estimate assumes

  • The appliance draws its full stated wattage the whole time it is on. Real units with a thermostat cycle off and cost less.
  • Wattage is the typical label value, not a measured value. Check the label on your own appliance.
  • The rate is an approximate residential average. Your bill may include fixed fees, tiers or time-of-use pricing. Edit the rate above.
  • A month is 30 days and a year is 365 days.

Read the full calculation methodology

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