How much does it cost to run a dehumidifier?
A typical dehumidifier (≈270 W) costs about 7p an hour and 57p for 8 hours at the UK price cap, or about 5¢ an hour at the US average. Calculator, measured ranges and tips.
- Per hour of use
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- Per day
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- Annual consumption
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Results are indicative estimates based on the values you enter. Always check your appliance labels, your tariff and the manufacturer’s data.
- Which? measured running costs from 3p to 17p an hour at the October 2026 price cap, with Best Buys averaging about 7p: that is roughly 115 W to 650 W, about 270 W for a typical model.
- UK (26.32p/kWh): a 270 W dehumidifier costs about 57p for 8 hours, or about £102 for 8 hours a day over six months.
- US (18.31¢/kWh): about 5¢ an hour and $71 for the same six-month scenario.
- Refrigerant (compressor) models are cheapest to run in heated rooms; desiccant models use more power but work better in cold spaces.
The calculator is preset for a 270 W dehumidifier running 8 hours a day for 180 days (the damp season) at the UK price cap rate. Enter your model’s wattage from its rating plate or manual and how long it really runs. If it has a humidistat, it switches off once the target humidity is reached: lower the “share of time at full power” accordingly.
How much power does a dehumidifier use?
Which? measures the energy use of every dehumidifier it tests. At 26.32p per kWh, it reports about 7p an hour on average for its Best Buys, 3p for the most efficient and 17p for the least efficient models. Converted to power (cost ÷ price per kWh):
| Profile | Equivalent power (Wisiko calculation) |
|---|---|
| Very efficient | ≈ 115 W |
| Typical Best Buy | ≈ 270 W |
| Power-hungry | ≈ 650 W |
Running costs
| Power | UK per hour | UK 8 h/day for 180 days | US per hour | US 8 h/day for 180 days |
|---|---|---|---|---|
| 115 W | 3p | £44 | 2¢ | $30 |
| 270 W | 7p | £102 | 5¢ | $71 |
| 650 W | 17p | £246 | 12¢ | $171 |
Power is not the whole story: what matters is how much water the unit removes per kWh. A slightly more powerful but more efficient model can dry the room faster and switch off sooner. Which? publishes a cost per litre of water extracted for this reason.
Refrigerant or desiccant?
- Refrigerant (compressor): damp air passes over a cold coil where water condenses. Most efficient in heated rooms, less effective in cold garages or cellars.
- Desiccant: an absorbent wheel captures moisture and a heater dries it out again. Uses more electricity but works well in the cold and gives off a little warmth.
Dehumidifier or tumble dryer for laundry?
A dehumidifier in a small closed room speeds up drying clothes on an airer. A 270 W refrigerant model running 6 hours uses about 1.6 kWh: similar to one heat pump dryer cycle (about 1.3 kWh) and far less than a condenser cycle (about 3.4 kWh). Compare with our tumble dryer cost calculator.
Cut the damp and the cost
- Ventilate briefly every day and keep extractor fans and trickle vents working.
- Use the cooker hood when cooking and the bathroom fan after showers.
- Set the humidistat to a sensible level rather than running flat out.
- Close doors and windows in the room being treated.
- Clean the filter regularly.
- If damp comes from a leak, rising damp or penetrating rain, a dehumidifier only treats the symptom: get the cause diagnosed.