A cool-mist humidifier typically uses about 20-50 watts, while warm-mist models that boil water use roughly 200-300 watts. There is no meaningful startup surge.
- Running watts
- 40 WTypical; 20–300 W across models
- Starting watts
- NoneNo motor surge
- Per day
- 0.4 kWh10 h of use
- Current
- 0.3 AAt 120 V while running
Figures checked against DOE, ENERGY STAR and manufacturer data on . Your model's label is the final word.
Watts by model and setting
Most humidifier models draw between 20 and 300 W while running; a typical one draws about 40 W. Assumes a cool-mist (ultrasonic or evaporative) unit around 40 W for 10 hours; a warm-mist unit near 280 W would use about 2.8 kWh over the same time.
- Type: ultrasonic and evaporative (cool-mist) units use tens of watts; warm-mist/steam units heat water and use hundreds
- Mist output setting and fan speed
- Room size and run time
- Hybrid models with both modes draw far more when warm mist is on
Running a humidifier on a generator or power station
- Generator: at least 40 running watts. A generator rated 1,000 W or more covers it with room to spare.
- Power station: continuous output of at least 40 W. Pure sine wave output is the safe choice for motors and electronics.
| Power station capacity | Estimated runtime |
|---|---|
| 500 Wh | 10.6 h |
| 1,000 Wh | 21.2 h |
| 2,000 Wh | 42.5 h |
| 3,000 Wh | 63.8 h |
Based on 40 W average draw and 85% usable capacity.
- Cool-mist humidifiers are an easy load for any power station; a 500 Wh station can run one through the night
- Warm-mist models draw several hundred watts and drain batteries quickly
- Use a pure sine wave inverter for ultrasonic units, which have electronic drivers
- If a generator is in use, keep it outside and use a CO alarm indoors
Add it to the generator calculator
Questions people ask
Do warm mist humidifiers use more electricity?
Yes. They heat water, so they typically draw around 200-300 W, versus about 20-50 W for ultrasonic or evaporative cool-mist models.
Can I run a humidifier on a battery power station?
A cool-mist model is easy to run for many hours; a warm-mist model will use a 1,000 Wh battery in a few hours.