Dehumidifiers
A dehumidifier pulls water out of the air. It's worth it when a room stays damp after the free fixes (ventilation, less moisture made indoors, steady heating), or when you need to dry washing indoors.
Tools
Guides
- What size dehumidifier do I need?How to size a dehumidifier for a room or home: extraction rate vs tank size, the manufacturer's size bands, and when to pick desiccant for a cold room.
- How much does a dehumidifier cost to run?Work out what a dehumidifier costs to run per day, week and winter: watts × hours × your unit rate. Worked example and free calculator.
- Compressor vs desiccant dehumidifier: which for a cold house?How compressor and desiccant dehumidifiers work, which suits a heated room or a cold garage, loft or conservatory, and what each costs to run.
- Dehumidifier litres per day: read the test conditions before the headlineA dehumidifier's litres-per-day rating depends on the temperature and humidity it was measured at. See a manufacturer's own two-condition example and how to compare fairly.
- Dehumidifier vs tumble dryer for laundry: cost per loadCompare the cost of drying a load of washing with a dehumidifier or a tumble dryer, using your machine's figures and your own unit rate.
The two main types
- Compressor dehumidifiers cool air over a cold coil so the water condenses out. They suit heated, lived-in rooms.
- Desiccant dehumidifiers draw water out with an absorbent material and a small heater. They keep working in cold rooms, such as an unheated garage or loft, where compressor models extract less.
Size and running cost
Size is about how much water a machine can extract a day, matched to the space. We only show sizes taken from a manufacturer's published sizing guide. Running cost is simple maths: the machine's power in watts, times the hours it runs, times your electricity unit rate. Our calculator does both with your own figures.
Dehumidifier size and running-cost calculator
Pick compressor or desiccant for your room, see the size band from the manufacturer's guide, and work out the running cost per day, week and season on your own tariff.
Sources
- Desiccant dehumidifiers keep working in cold rooms, where compressor models extract less (Manufacturer documentation), awaiting check
- Manufacturer sizing guide: extraction capacity by home size (Manufacturer documentation), awaiting check
- NHS guidance on damp and mould and your health (NHS), awaiting check