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What size dehumidifier do I need?

For one room or a small flat, a 10L compressor dehumidifier is usually enough. Most 2-bed and 3-bed homes suit 12L, a 4-bed home suits 20L, and 5 or more bedrooms suit 25L. Go up a size for a big household or lots of washing dried indoors, and choose a desiccant model for rooms colder than about 15°C.

Answer the questions below to get a size for your home or room. The rules come from published guidance by UK dehumidifier makers Meaco and Ebac, not from our own tests.

Find your dehumidifier size

Answer a few quick questions. The answer updates as you go.

What do you want to dry out?
How big is your home?
How many people live there?
Do you dry washing indoors most weeks?
Do you have mould, or windows streaming with water most mornings?
Does it get colder than about 15°C in winter?
Our suggestion
A 12L compressor dehumidifier
  • Meaco suggests a 10L or 12L model for a 2-bed home. We pick 12L to give you a little spare.

Do not expect it to fill with 12 litres a day. That figure is a lab maximum. Ebac says a home like yours usually needs to remove about 1.5 litres of water a day to stop condensation and damp.

Our buying guides for this:

Dehumidifier size by home

Compressor sizes for a heated home with an average household, based on Meaco’s guidance. The size is the maker’s litres-a-day rating.

HomeSuggested sizeBusier or damper home
One room10L12L to 15L for a laundry room (Ebac)
Studio or 1-bed home10L12L with 5+ people, lots of indoor washing or mould
2-bed home10L to 12L20L with 5+ people, lots of indoor washing or mould
3-bed home12L20L with 5+ people, lots of indoor washing or mould
4-bed home20L25L with 5+ people, lots of indoor washing or mould
5+ bed home25L or more25L is the minimum Meaco suggests

Every home is different. Older, colder or very damp homes may need more drying power.

How it's worked out

Starting size. We start from Meaco’s size guidance for single rooms and homes by number of bedrooms, and Ebac’s suggestion of 12L to 15L for one laundry area.

Going up a size. Meaco says the number of people matters, because showering, cooking, washing and breathing all add moisture. We go up one size (once at most) if five or more people live there, if you dry washing indoors most weeks, or if you already have mould or streaming windows.

Cold rooms. Meaco says that below about 15°C a desiccant dehumidifier works better than a compressor one, so for cold rooms we suggest a desiccant model instead of a size.

Real-world water. Litre ratings are measured in warm, very humid conditions. Ebac says most homes only need to remove about 1.5 to 2 litres a day, so do not worry if your tank fills more slowly than the rating suggests.

Before you buy

  • Look for a humidity setting, so it switches off once the room is dry enough.
  • Check the tank size. A bigger tank, or a drain hose, means less emptying.
  • For a bedroom, check the noise claim and whether it has a night or sleep mode.
  • A dehumidifier helps control moisture. It will not fix a leak, rising damp or a broken extractor fan.

Ready to choose? Our dehumidifiers under £100 guide covers 10L to 16L budget models, and our best dehumidifiers UK hub covers bigger compressor and desiccant picks.

Common questions

What size dehumidifier do I need?

For a single room, small flat or 1-bed home, a 10L compressor dehumidifier is usually enough. A 2-bed or 3-bed home suits a 12L model. A 4-bed home suits 20L, and 5 or more bedrooms suit 25L or more. Go up a size if lots of people live there or you dry washing indoors. This follows guidance from UK makers Meaco and Ebac.

Do I need a 12L or 20L dehumidifier?

A 12L model suits most 2-bed and 3-bed homes. Choose 20L for a 4-bed home, a busy household of five or more, or a 3-bed home where you dry a lot of washing indoors or already have mould. A bigger model dries the air faster, but it costs more and is usually bigger and heavier.

What size dehumidifier do I need for a bedroom?

A 10L compressor model suits most heated bedrooms. If the room has mould or the windows stream every morning, a 12L model will dry it faster. For quiet night modes, see our dehumidifier for damp bedroom guide.

What size dehumidifier do I need to dry clothes?

Ebac suggests a 12L to 15L model for one laundry area. If you dry washing for a family in the same room every week, a 20L model will dry it faster. Our dehumidifier for drying clothes guide compares laundry modes.

What size dehumidifier do I need for a 3 bedroom house?

Meaco suggests a 12L model for a typical 3-bed house of about 100 to 130 square metres. It suggests 20L for a 3-bed with a larger household, such as six people, because more showering, cooking and washing means more moisture.

What does 10L or 12L actually mean?

It is the most water the dehumidifier can take out of the air in 24 hours in the maker’s test, which is usually warm and very humid. In a normal UK home it will collect much less. Use the figure to compare models, not as a promise.

How much water should a dehumidifier collect a day?

Less than you might think. Ebac says most UK homes only need to remove about 1.5 litres a day for two people, or about 2 litres for five, to keep condensation and damp under control. You may collect more in the first few days if the home is very damp.

Is a bigger dehumidifier better?

Not always. A bigger model dries the air faster and can cope with more moisture, but it costs more to buy and is bigger to store. Most models switch off when the room reaches the humidity you set, so a slightly bigger model does not have to run all the time.

Which type of dehumidifier is best for a cold room?

A desiccant dehumidifier. Meaco says that below about 15°C a desiccant model works better, because compressor models slow down in the cold. That makes desiccant models a better fit for garages, conservatories and unheated rooms.

How much does a dehumidifier cost to run?

The budget 10L to 12L compressor models in our under £100 guide list 187W to 300W. Use our appliance running cost calculator to work out the cost for your hours at the UK price cap.

Sources

Guidance checked 7 October 2026.

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