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How Much Electricity Does a Humidifier Use?

Compare the energy costs of cool mist and warm mist humidifiers.

3 min readUpdated July 28, 2026WattPocket
A cool mist humidifier running on a nightstand.

Related wattage and runtime estimate

This supporting tool converts watts and equivalent full-power hours per day into daily, 30-day, and yearly energy costs. It does not replace the guide-specific formula below.

A 40W cool mist humidifier running for 12 hours overnight uses minimal power compared to a warm mist model.

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$2.71/ month
$0.09/ day
$32.99/ year

This setup uses about 14 kWh in a 30-day month.

01

Cool mist vs. warm mist

The cost of running a humidifier depends entirely on the type you own. Ultrasonic and evaporative (cool mist) models just run a small fan or oscillator, drawing about 20 to 50 watts. Warm mist models use a heating element to boil water, drawing 200 to 400 watts.

Formuladaily cost = (watts ÷ 1,000) × hours used × rate per kWh
02

Running it overnight

Running a cool mist humidifier for 8 hours every night costs next to nothing—often less than a dollar per month. A warm mist model running for the same amount of time will have a noticeable impact on your bill.

03

Maintenance matters

If your humidifier has a filter or wick, hard water minerals will clog it over time. A dirty filter blocks airflow, forcing the fan to work harder. Regular cleaning keeps the unit efficient.

Rate source and limits

The default rate is the EIA U.S. residential average for April 2026, retrieved July 16, 2026. It is an average revenue per kilowatt-hour, not a quote for your utility plan. Fixed fees, taxes, tiers, and time-of-use prices can change the bill.

Open the EIA source

Related electricity-cost guides

  1. How Much Does It Cost to Run an Air Conditioner Per Hour?
  2. How Much Electricity Does a Refrigerator Use Per Month?
  3. How Much Electricity Does a Dehumidifier Use?