Updated 2 November 2026 · By Diego Gómez
What size dehumidifier do I need?
Simple rules for choosing a 10L, 12L, 20L or desiccant dehumidifier for a UK bedroom, flat or house, plus a free calculator.
Dehumidifiers are sold by how many litres of water they can remove per day. The figure on the box is measured in warm, very humid conditions (often 30 °C and 80% humidity or more), so in a British home in winter they extract less.
| Where | Recommended |
|---|---|
| Bedroom or small room with condensation | 10–12 L/day compressor |
| Flat or 2-bed house, laundry indoors | 12–20 L/day compressor |
| 3–4 bed house, mould in several rooms | 20 L/day or more |
| Unheated room, garage, conservatory (under ~15 °C) | Desiccant, 8–10 L/day |
Compressor or desiccant?
Compressor dehumidifiers are cheaper to run and best in heated rooms. Desiccant models keep working in the cold and are lighter, but use more electricity. See desiccant dehumidifiers.
Work it out for your home with our dehumidifier calculator.
Recommended
Pro Breeze OmniDry 12L
- 12 L/day
- up to 15 m²
- 2 L
The best-selling dehumidifier on Amazon UK right now: 12 litres a day, automatic humidity sensor, laundry mode and a drain hose option.
EcoAir DD2 Simple (desiccant)
- 9 L/day
- 1 °C
- 3 L
A light desiccant dehumidifier that keeps working in cold, unheated rooms down to 1 °C, where compressor models struggle.
ThermoPro TP49 hygrometer (4-pack)
- temperature and humidity
- 4
- AAA
Cheap digital hygrometers with a comfort-level face.
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FAQs
Is a bigger dehumidifier better?
A bigger one removes moisture faster and then switches off when it reaches your target humidity, so it isn't wasteful. Too small a model will run all day and never catch up.