Cost to Run a Window Fan Calculator

Estimate how much it costs to run a window fan based on wattage, daily usage, speed setting, and your electricity rate. A practical baseline is 55 watts for 10 hours per day during milder cooling weather.

Fast estimate No signup Updated for 2026 rates

Typical electricity cost

How much does a Window Fan cost to run?

Based on typical usage

A Window Fan typically uses about 33 to 55 watts, costing around $0.01 per hour at $0.15 per kWh.

At typical use (10 hours per day), that's about $2.48 per month and $9.92 for a typical 4-month cooling season.

Per hour $0.01
Daily $0.08
Monthly $2.48
Cooling season $9.92

Based on

  • 55 watts
  • 10 hours per day
  • High speed setting
  • $0.15 per kWh
  • 4-month cooling season

What affects cost most

  • Average hours used per day
  • Electricity rate in dollars per kWh
  • Speed or performance setting
  • How many active days or months the device runs each season

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

Effective wattage at High speed: 55 W

Keep wattage as the base rating. The selected speed changes the effective wattage used in the estimate.

2. Usage

Quick presets

3. Rate

Enter your values and click Calculate Cost.

How Much Electricity Does a Window 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 6 hours per day and High speed
    $1.49/month
  • Typical Use 10 hours per day and High speed
    $2.48/month
  • Heavy Use 14 hours per day and High speed
    $3.47/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
  • Speed or performance setting
  • How many active days or months the device runs each season

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.
  • Use the matching speed or power setting so the wattage estimate tracks the way you really run it.
  • Run the fan when outdoor air is cooler than indoor air for the best payoff.
  • Use lower speeds overnight when strong airflow is no longer necessary.
  • Seal unused gaps around the window insert so hot air does not leak back in.

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