Cost to Run a Whole House Fan Calculator

Estimate how much it costs to run a whole house fan based on wattage, daily usage, and your electricity rate. A practical baseline is 450 watts for 6 hours per day during warmer evenings.

Fast estimate No signup Updated for 2026 rates

Typical electricity cost

How much does a Whole House Fan cost to run?

Based on typical usage

A Whole House Fan typically uses about 450 watts, costing around $0.07 per hour at $0.15 per kWh.

At typical use (6 hours per day), that's about $12.15 per month and $48.60 for a typical 4-month cooling season.

Per hour $0.07
Daily $0.41
Monthly $12.15
Cooling season $48.60

Based on

  • 450 watts
  • 6 hours per day
  • $0.15 per kWh
  • 4-month cooling season

What affects cost most

  • Average hours used per day
  • Electricity rate in dollars per kWh
  • How many active days or months the device runs each season
  • Weather, insulation, and thermostat behavior

How it works: Daily cost uses wattage, hours per day, and electricity rate. Monthly uses daily × 30; cooling season uses monthly × 4.

Use the calculator below to estimate cost based on your own wattage, usage time, and electricity rate.

Calculator

1. Device

2. Usage

Quick presets

3. Rate

Enter your values and click Calculate Cost.

How Much Electricity Does a Whole House Fan Use?

These example monthly costs show how active-season runtime changes the bill faster than small wattage differences do.

Example monthly costs

  • Light Use 3.6 hours per day
    $7.29/month
  • Typical Use 6 hours per day
    $12.15/month
  • Heavy Use 8.4 hours per day
    $17.01/month

Get a better estimate and keep costs down

Defaults are a starting point. Real cost changes most when runtime, wattage, and your electricity rate differ from the benchmark assumptions.

What changes cost most

  • Average hours used per day
  • Electricity rate in dollars per kWh
  • How many active days or months the device runs each season
  • Weather, insulation, and thermostat behavior

How to get a better estimate and lower cost

  • Replace the default electricity rate with the actual rate from your latest power bill.
  • Adjust daily runtime to match how long you actually use the equipment.
  • Run it during cooler outdoor temperatures for the best payoff.
  • Open windows strategically to improve the airflow path.
  • Use timers so it does not run longer than needed.
  • Pair it with insulation and attic ventilation improvements.

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