What a dehumidifier really costs to run in the UK (2026 prices)
At the October 2026 cap of 26.32p per kWh, here is the true cost of running a dehumidifier — and how it compares with a tumble dryer or an electric heater.
5 min readUpdated 8 September 2026 Written by Dave B, Warrington
The short answer
A 300 W dehumidifier run 6 hours a day costs about 47p a day, £14 a month, at the 26.32p capped unit rate. Compressor models cycle on and off, so real bills are often lower than the label suggests.
The formula, and a real example
Running cost = wattage x hours ÷ 1,000 x price per kWh. The Ofgem cap for 1 October to 31 December 2026 sets electricity at 26.32p per kWh (plus a 54.83p daily standing charge you pay regardless), so use 26.32p unless your own bill says otherwise.
A 300 W dehumidifier run 6 hours a day uses 1.8 kWh — about 47p a day, £14.20 a month, or £173 a year if you ran it that way all year. A 165 W compact model at the same usage is around 26p a day. A 700 W desiccant unit is around £1.11 a day.
Compressor dehumidifiers only draw full power when the compressor is running; on a humidistat setting they cycle, so actual use can be well under the label figure. A plug-in energy monitor gives you the true number for a few pounds.
- 300 W x 6 h = 1.8 kWh = 47p/day at 26.32p
- 300 W x 12 h = 3.6 kWh = 95p/day
- Halving runtime halves the cost — a humidistat does this automatically
Cheaper than the alternatives
A vented tumble dryer typically draws 2,500-3,000 W. An hour and a half of drying is around 4 kWh, or roughly £1.05 at capped rates. Drying the same load on an airer with a 300 W dehumidifier running four hours costs about 32p.
A 2 kW plug-in electric heater costs about 53p an hour. Heating a damp room to dry it is almost always dearer than dehumidifying it — and drier air feels warmer at the same thermostat setting, so the dehumidifier can shave heating cost too.
Cut the running hours, not just the wattage
Fix the moisture source before buying more machine: extractor fans that genuinely vent outside, lids on pans, no laundry on radiators, and trickle vents left open. Then run the dehumidifier in a closed room with the door shut, on a humidistat set to 50-55% relative humidity rather than continuous mode.
Desiccant models work better in unheated spaces like garages and cold conservatories but use more electricity for the same water removed. Compressor models are the cheaper choice in a normally heated house.
Put a number on it
Sources
General information only, not financial advice. Figures are illustrative UK averages — check your own bill, mortgage offer or contract. Speak to an FCA-regulated broker before making a mortgage decision.