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9 June 2021

How to buy the best dehumidifier

Looking for the best dehumidifier to help tackle condensation, damp and mould? We'll help you find the best dehumidifier for you.
Christina Woodger
Dehumidifier2 in room 479432

If you’re noticing water stains on your walls or ceiling, condensation on your windows, mould lurking in your shower or a general musty smell, a dehumidifier could be the solution. Buy the wrong one, though, and it won't do much to tackle your damp problem. 

Read on to find out what your options are, including whether you need a refrigerant (compressor) or desiccant dehumidifier, plus features to look for. 

We'll also help you avoid overspending or ending up with a dehumidifier that's not suited to your needs and simply won't draw water from the air successfully. Whether you're on a tight budget, or you're prepared to spend more, we'll help you find the most appropriate dehumidifier. 

Best dehumidifiers for 2021

We’ve tested a range of dehumidifiers from different brands, including Ebac, Ecoair, Meaco and DeLonghi, to uncover the best dehumidifiers. 

  • 85%

    This large-capacity refrigerant does a great job of extracting moisture from the air. It's also easy to use, and it runs quietly, so you don't need to worry about it disturbing you too much if you're working or studying from home. It's energy-efficient, too. Just be aware that it's large and bulky.

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  • 81%

    Small but mighty - and very versatile. It works well in warmer and colder rooms, it's lightweight, making it easily portable, and it runs quietly. A great choice if you want a dehumidifier for both heated rooms and unheated areas such as a garage, boat or caravan.

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  • 81%

    This dehumidifier is energy-efficient, easy to use and - most importantly - great at extracting water from the air. It's versatile, working well in both warmer and colder conditions, making it a great choice if you're likely to need to use it in both a heated lounge, say, and unheated garage.

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  • 77%

    This model has been on the market a while, but it's still one of the best. It's nice and quiet, too. Unusually for a refrigerant model, it works well in colder environments as well as warmer ones. It's also energy-efficient, easy to use and quiet.

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Last updated June 2021

Read below for more information on how to choose the best dehumidifier for you, as well as how much you should spend. Know what you want already? Head over to our dehumidifier reviews.

Refrigerant and desiccant dehumidifiers - what’s the difference?

There are two main types of domestic dehumidifier: refrigerant and desiccant. As we explain below, they use different technology. Each type has its advantages.

Refrigerant (or compressor) dehumidifiers

Refrigerants are more popular in the UK because they have a reputation for being more efficient with energy. Desiccants tend to release more heat to the room, which might be nice if you want a mild heating effect, but isn't necessary in a home that's already heated. 

You'll have more choice if you're looking for a refrigerant, as there are more of them on the market.

Refrigerants work by creating a cold surface. When warm, damp air comes into contact with the cold surface, condensation forms and drips into the water tank. 

They're generally only effective in a heated room, because they rely on the cold surface within the dehumidifier being colder than the air in the room. If the temperature in the room drops too low, it will be colder, and not warmer, than the cold surface within the dehumidifier. 

And if the room gets too cold, the dehumidifier's coils start to freeze. The dehumidifier's automatic defrost function will then kick in, and the dehumidifier will spend time and energy defrosting rather than dehumidifying.  

However, we've found a few unusual refrigerant dehumidifiers that work well in lower temperatures, too. 

Refrigerant dehumidifiers are often noisier than desiccant dehumidifiers, too, although that isn't always true: we have tested some that are very quiet. 

Desiccant dehumidifiers 

Desiccant dehumidifiers work differently. These use an adsorbent material to extract water from the air, in a similar way to a sponge. The desiccant is regenerated by an internal heater, and the moisture drips into the water condenser. 

As they're not reliant on the temperature on the room being warm, desiccant dehumidifiers work more effectively than refrigerant dehumidifiers in colder temperatures of 15°C or less. 

So, if you're looking for a dehumidifier for an unheated garage, conservatory or other out-building, you should generally opt for a desiccant. 

Take a look at our best dehumidifiers to discover the models that Which? recommends.

How much do dehumidifiers cost?

Dehumidifiers can cost anything from around £40 to £450. The amount you spend largely depends on the dehumidifier’s capacity and any extra features it comes with.

Cheap vs expensive dehumidifiers

If you’re already grappling with a damp problem, having to fork out for a dehumidifier can feel like a kick in the teeth. So can you get away with a cheap one? There are a few factors to consider.

The cheapest dehumidifiers usually have a smaller capacity. Dehumidifiers that cost less than £130 tend to have a capacity of 10 litres or less.

Cheaper dehumidifiers also tend to have fewer features than more expensive ones. A cheap dehumidifier is less likely to have castors or wheels or a laundry setting. 

Most dehumidifiers have a built-in humidistat regardless of price, however. This allows you to specify a relative humidity (RH) that you want the dehumidifier to try to create in the room. 

Some also have an auto setting. How the auto setting works will vary from brand to brand, but generally speaking the dehumidifier will monitor and regulate conditions in the room according to what it deems to be the most appropriate RH at that point in time. 

Most dehumidifiers have a digital or analogue display, although a handful have just have an on/off switch.

Cheap dehumidifiers aren't necessarily less reliable than more expensive ones. In 2019 we asked more than 500 dehumidifier owners to tell us how long their machines had lasted, and what had gone wrong if they broke down. As a general rule, dehumidifiers were rated highly for their reliability, meaning they’re unlikely to develop faults. 

The dehumidifier brand that was rated least reliable still had 72% of products staying fault-free after six years – which is better than many other home appliances.

You'll need to spend at least £130 to get a reasonable dehumidifier. Those we've tested below that price haven't proven very effective. Beyond that, though, there isn't any correlation between price and performance. 

One dehumidifier we tested, for example, costs nearly £270 but scores only 50%, as it doesn't tackle humidity as swiftly as many others and is very noisy. Another cost £450 and scored 59%. It's not a terrible model, but you'd certainly be annoyed if you spent that much and then found out you could have spent more than £300 less on a better one: one of our Best Buys costs just £130. 

Want to know which models we're talking about? Check out our list of best dehumidifiers to discover which models are rated as Best Buys. 

How much do dehumidifiers cost to run?

The good news is that you probably don't need to worry too much about a dehumidifier adding enormously to your energy bills. A 250W dehumidifier, running for four hours at a time, twice a week, should cost around £19.50 a year to run. 

That said, some are much slower at extracting water from the air than others. This means you’ll have to use them for longer, which will increase the amount of energy you use.

What size or capacity dehumidifier?

A dehumidifier's size or capacity describes how many litres of water it's able to extract from the air each day, rather than its physical size or the capacity of its water tank (although dehumidifiers with a larger extraction rate are often larger and contain larger tanks). 

Dehumidifiers for homes range in capacity from 7 litres to 25 litres. The best-sized dehumidifier for your needs depends on the size of the space you want to use it in, how many people are living in the home generating moisture through activities like cooking, washing and doing laundry, and the extent of your damp problem. 

As a general guide:

  • 7 to 12 litres – this a small capacity. A refrigerant dehumidifier of this size would be suitable for a single person living in a small flat, looking for a lightweight and portable machine to tackle a mild damp problem – say, mould tends to develop and you need to manage it. 
  • 14 to 16 litres – medium capacity. Choose one with a medium capacity if there are more of you creating moisture through activities such as showering, cooking and washing clothes at home, and/or your damp problem is more severe or more widespread across your home. 
  • 18+ litres – large capacity. Go for one like this if you have a big home, you have a lot of moisture that you need to get rid of fast – you're clearing up after a flood for example – or you're persistently adding lots of water to the air through drying lots of laundry indoors. 

These figures are just here to get you started, though.

Because desiccants can be more powerful than refrigerants, a desiccant dehumidifier can cover a larger area than a refrigerant of the same claimed capacity. 

And, even within refrigerants and desiccants, two models with the same claimed capacity could vary enormously in effectiveness – the only way to be sure which dehumidifiers are going to do a good job is to check our reviews. 

You should also bear in mind that manufacturer claims about capacity (water extraction rate) are often based on conditions you're unlikely to experience in your home. For refrigerant dehumidifiers, manufacturers frequently base their claims on 30ºC and 80% relative humidity – conditions which better represent a tropical rainforest than a typical British home. 

That's because the higher the temperature, and the higher the humidity level, the more effectively a refrigerant dehumidifier will work. So, if a dehumidifier has a capacity of 18 litres, this doesn't mean you should expect it to extract 18 litres of water a day from your home. 

We test all dehumidifiers in realistic conditions to help you pick the right one. We measure how much water each dehumidifier pulls from the air at 21ºC and 10ºC, both with 59% relative humidity.

Small dehumidifiers

If you've got a small home, you won't want a hulking dehumidifier taking up precious space.

The smallest dehumidifiers have a capacity of 7 to 10 litres. Size-wise, these smaller models will range between 18cm x 38cm x 18cm, and 36cm x 55cm x 33cm (w x h x d). 

What features do dehumidifiers have?

Here are some of the features to consider when shopping for a dehumidifier:

  • Continuous drain facility Many dehumidifiers allow you to connect a hose and flush the collected water directly away to a low-level drain. This will save you from emptying the water tank yourself, or prevent the machine from getting full and switching off if you're not around to empty it. You need to think through how this is going to work in your home, though. Dehumidifiers with this function often don’t come with a hose in the box, so you’ll have to buy it separately.
  • Humidistat Most have a humidistat. Like a thermostat, this monitors moisture levels in the air and adjusts the dehumidifier to maintain the humidity level you’ve selected. Some dehumidifiers also have a more nuanced auto setting, where the dehumidifier adjusts its settings according to its idea of the most appropriate relative humidity. These settings save you from repeatedly having to fiddle with the controls yourself. 
  • Integrated cord storage For saving space when the dehumidifier isn’t in use, and removing the risk of tripping over a sprawling cable. Not an essential, but nice to have.
  • Timer Allows you to program the dehumidifier to turn on and/or off after a specified time. This could help you save money if you're on a tariff offering cheaper energy at certain times of day, or if you want to leave the dehumidifier on for a few hours after going out, but you don't need it on all day. You may find it easier to set the humidistat, though, or to use the auto setting if it has one. 
  • Laundry setting If you don’t have a tumble dryer, and it’s too cold to hang wet clothes outside (or if you don’t have access to a garden or balcony where you could put up a clothes line), then a dehumidifier can help you dry your clothes. Some come with a laundry setting, but you can use any dehumidifier for this if yours doesn't have one. Many laundry settings just whack up the power to max for a set time, although some are more sophisticated and are designed to save you energy too by optimising the dehumidifier's performance so it works as hard as it needs to and no harder. Manufacturers say that a dehumidifier will leave your clothes softer than a tumble dryer would. Hanging clothes on a radiator can cause condensation, so you should always avoid doing that. 
  • Wheels/castors Could come in useful if your dehumidifier is heavy (they can weigh from 6kg to more than 16kg).

Which dehumidifier brand is best?

Some dehumidifier brands routinely do well or badly, while others are a lot more hit and miss. 

Click on the links below to find out how models from different brands fare: