United Kingdom Cooling and fans
How much does it cost to run a dehumidifier?
A compressor dehumidifier is a small refrigeration unit, and it is one of the appliances people most often leave running 24 hours a day. The humidistat switches the compressor off when the air is dry enough, so the real draw is well under the rating most of the time.
A 250 watt dehumidifier costs about 3.9p an hour to run in Great Britain at 26.32 pence per kWh. Running it 24 hours a day cycling 60% of the time comes to about 95p a day, £28.84 a month and £346.08 a year.
- Price: Ofgem cap, Oct to Dec 2026
- Wattage range with its source
- Checked 26 October 2026
Uses 3.6 kWh a day, 110 kWh a month, at 26.32 pence per kWh (Great Britain (price cap average)).
The dial places the daily cost between a 50 watt fan and a 4.5 kW water heater on 2.5 hours a day.
A 250 watt dehumidifier costs about 3.9p an hour to run in Great Britain at 26.32 pence per kWh. Running it 24 hours a day cycling 60% of the time comes to about 95p a day, £28.84 a month and £346.08 a year.
What this assumes
The default is a 250 watt dehumidifier running 24 hours a day, drawing full power 60% of the time it is switched on (the rest of the time a thermostat or sensor has it idle). Published typical ratings run from 150 to 400 watts. Your label or manual gives the exact figure, and the calculator takes it.
The price is the Ofgem price cap unit rate for 1 October to 31 December 2026, average for England, Scotland and Wales, paying by Direct Debit. The cap for 1 January to 31 March 2027 is announced in late November 2026. A fixed tariff, a time-of-use plan or a different payment method changes the rate, which is why the rate field is editable.
Cost by wattage and hours at the price cap rate
At 26.32p per kWh, running flat out. Multiply by the share of the time your thermostat keeps the element on.
| Power | 1 hour | 8 hours | 24 hours | A week at 24 hours a day |
|---|---|---|---|---|
| 150 watt | 3.9p | 32p | 95p | £6.63 |
| 250 watt | 6.6p | 53p | £1.58 | £11.05 |
| 400 watt | 11p | 84p | £2.53 | £17.69 |
How a dehumidifier uses electricity
Typical US basement units (35 to 50 pints a day) draw 300 to 700 watts. UK homes mostly use smaller 10 to 20 litre units at 150 to 400 watts, and desiccant models that draw more but work better in cold rooms.
A unit that is sized for the room and set to 50 to 55% humidity will cycle, running perhaps 60% of the time. An undersized unit in a wet basement runs flat out, so set the duty to 100% if the tank fills twice a day.
Dehumidifiers warm the room slightly, which is useful in winter and unwelcome in summer.
Ways to cut the cost
- Set the humidistat to 50 to 55%. Lower settings cost more and do nothing extra for mould.
- Empty the tank or fit the drain hose so it never sits idle with a full tank.
- Close windows and doors in the space you are drying.
Questions people ask
How much does it cost to run a dehumidifier 24/7?
A 500 watt unit at 60% duty uses about 7.2 kWh a day. At 18 cents that is about 1.30 dollars a day or 39 dollars a month. A 250 watt UK unit at 26p is about 94p a day.
Are desiccant dehumidifiers more expensive to run?
Per hour, usually yes (400 to 700 watts), because they heat the desiccant. They extract more water in a cold room, so per litre of water removed they can match a compressor unit below about 15 degrees Celsius.
Other cooling and fans costs
More in the UK
Sources
The electricity price on this page is read from the data file that also lists the release it came from. The wattage range is a published typical range, not a measurement of your appliance.