Which dehumidifier to buy for a UK home: compressor or desiccant, and what size

The first question is how warm the room is. That decides the type of dehumidifier, and the type decides most of the running cost.

Compressor or desiccant

Compressor models cool a metal coil so that water condenses on it. They use less electricity, but they need warmth to work well. Meaco says compressor machines are only effective above 10°C and at their best from 16°C upwards. EcoAir puts the point where efficiency drops at 15°C.

Desiccant models pull moisture into an absorbent wheel and heat it out again. They keep working in the cold: the Meaco Zambezi is rated from 1°C. They draw more power and blow out warmer air, and they tend to be lighter.

In short: a heated home wants a compressor, and an unheated garage, conservatory, cellar or boat wants a desiccant.

What the litre rating means

The big number on the box is measured in a hot, very humid room: 30°C and 80% relative humidity. A British home in winter is nothing like that, and real output is much lower. Meaco publishes both figures for the Arete Two 12L: 12 litres a day in test conditions, and 5.4 litres a day at 20°C and 60% humidity.

Desiccant makers usually quote output at 20°C and 60%, so an “8 litre” desiccant and a “12 litre” compressor are closer than the labels suggest. When you compare two machines, compare figures taken at the same temperature and humidity.

What size you need

There is no independent sizing standard that we could find. Meaco’s own guidance pitches its 12 litre model at flats and homes with one to three bedrooms, and its 20 litre model at houses with three to five bedrooms. If you dry laundry indoors or the house is visibly damp, go up a size.

What it costs to run

Under the Ofgem price cap for 1 October to 31 December 2026, electricity costs 26.32p per kWh for a typical household paying by Direct Debit. At that rate, using the makers’ stated power figures, our arithmetic gives:

Machine	Power	Cost per hour
MeacoDry Arete Two 12L (compressor)	136 W	about 3.6p
MeacoDry Arete Two 20L (compressor)	207 W	about 5.4p
Meaco DD8L Zambezi (desiccant, low)	351 W	about 9.2p
EcoAir DD1 Simple MK3 (desiccant, high)	580 W	about 15.3p

A machine with a humidistat stops when the room reaches the target, so it does not run every hour of the day. Your own rate may differ from the cap, so check your bill.

Drying laundry

Most models have a laundry mode that runs the fan at full speed. Makers quote drying times for a load of washing of around 6 hours for a compressor and 2 to 4 hours for a desiccant. These are manufacturers’ claims, and they depend on the room and the load.

Noise

If the machine will run in a bedroom or living room, look at the noise figure on the lowest setting. In our shortlist these run from 34 dB(A) to 41 dB(A). On full power most are between 44 and 50 dB(A).

A dehumidifier treats the symptom

Government guidance on damp and mould is about finding and fixing the cause: leaks, poor ventilation, cold surfaces and inadequate heating. A dehumidifier lowers moisture in the air while it runs. It will not repair a leaking gutter or a failed damp-proof course. If you rent, report damp and mould to your landlord in writing.