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How Much Does It Cost to Run a Humidifier in the UK? (2026)
Ultrasonic and evaporative humidifiers draw 20 to 50 watts. Warm mist models boil water and draw 250 to 300 watts, making them five to ten times more expensive to run.
A typical humidifier (40 W) costs £0.010 per hour, or about £3.12 per month at 10 hours a day in United Kingdom. Cheap to run
| Wattage | Per hour | Per day | Per month | Per year |
|---|---|---|---|---|
| Low (20 W) | £0.005 | £0.052 | £1.56 | £18.98 |
| Typical (40 W) | £0.010 | £0.10 | £3.12 | £37.96 |
| High (300 W) | £0.078 | £0.78 | £23.40 | £284.70 |
Formula: watts ÷ 1000 × hours × price per kWh. Typical use is 10 h/day ≈ 146 kWh per year.
In the UK, with electricity at £0.26 per kWh (source: Ofgem price cap 1 Jul–30 Sep 2026, 2026-07), a typical humidifier costs £0.010 per hour and about £37.96 per year at 10 hours a day. Each £1.00 of electricity buys roughly 96.2 hours of use.
How to lower the cost of running a humidifier
- Choose cool mist over warm mist. The humidity result is the same.
- Use a hygrometer and stop at 40 to 50 percent humidity.
- Clean it weekly. Mineral buildup makes ultrasonic models work harder.
In standby it draws about 1 W, which adds roughly 9 kWh (£2.28) per year if it is never unplugged.
Frequently asked questions
How much does it cost to run a humidifier all night?
A 40 watt cool mist unit for 10 hours uses 0.4 kWh.
Do warm mist humidifiers use a lot of electricity?
Yes. At 300 watts they use as much as a small heater.
Does a humidifier use power when the tank is empty?
Most shut off automatically and draw about a watt.
Cost by region
- United States (average)
- California
- Texas
- New York
- Florida
- Canada (average)
- United Kingdom
- Germany
- France
- Australia
- India