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30 Jul 2021

Why has my dehumidifier stopped working?

Dehumidifier owners reveal which faults their machines were most prone to
A dehumidifier

If the unpredictable summer weather has left your home feeling horribly humid, or you've had flooding or a ceiling leak, you might have found yourself dragging the dehumidifier out of the cupboard. But if you plug the machine in and it's not working properly, what's your next move?

Dehumidifiers draw moisture from the air to reduce humidity levels in your home, which will make you feel cooler and less sticky. If your dehumidifier hasn't been used since earlier in the year, though, you might have found that it's not working as you'd expect.

To uncover the most common dehumidifier problems (and what you can do about them), we've surveyed 1,000 dehumidifier owners about their experiences. Keep scrolling for a closer look at the results.

You might find that you don't need to chuck your dehumidifier away and buy a new one after all.

Shopping for a reliable dehumidifier? Our expert guide reveals which dehumidifier brand to buy in 2021.

Common dehumidifier problems

After crunching the numbers from our survey, we were able to identify the most common dehumidifier issues.

A complete failure was the most commonly recorded issue. A broken auto function or humidistat, uncomfortable noise levels and leaky water tanks were among the other problems raised.

  • 32% Complete failure
  • 17% Other fault
  • 14% Auto function or humidistat function not working
  • 11% Inconsistent performance
  • 11% Very noisy
  • 10% Leaks (5% water tank, 5% elsewhere in the machine)
  • 5% Broken power cable or plug
  • 2% Frosts up

Before you attempt anything technical, try the classic 'off and on again' trick - turn off the power, disconnect your dehumidifier and then hook it up again to see if a reset makes a difference. Try plugging it into a different plug socket, in case it's the power outlet that's the problem.

If that doesn't get you any results, check the manual to make sure the information we've provided is suitable for your model - inappropriate DIY repairs could invalidate your warranty.

How to fix a dehumidifier with a broken auto function or humidistat

A sizeable 14% of dehumidifier owners who told us about their faulty machine said the problem was a broken auto function or humidistat.

Most dehumidifiers have a humidistat for measuring the humidity in your room and responding accordingly to achieve the relative humidity you've requested. A few have an auto function (sometimes called 'smart function' or similar), which works slightly differently to achieve similar goals. These will determine the appropriate level of relative humidity for you, and work to achieve that.

If your dehumidifier isn't collecting as much water as you'd expect, there might be a very good reason for this (see 'Dehumidifier doesn't collect water').

If the humidistat or auto function is genuinely faulty, though, the dehumidifier won't have the right information to adjust itself to the conditions in your room.

If that's the case, you'll need to call the manufacturer or a professional.

Make sure you don't buy a dehumidifier with a poor humidistat function from the get-go. We check the humidistat function of every dehumidifier we test, and highlight those that don't work well in our dehumidifier reviews.

How to fix a noisy dehumidifier

An effective dehumidifier will remove excess moisture from the air, but if it starts to sound like a jet engine, you won't want to turn it on in the first place. In our survey, 11% of owners who experienced faults reported issues with noise levels, so you're not alone.

Some dehumidifiers are just noisier than others from the outset, as we highlight in our reviews. All dehumidifiers make some noise, but some will run discreetly in the background, while others are annoyingly loud, even on their silent/low/night mode.

If your dehumidifier has become noisier than usual, there are a couple of potential causes. First, check how the machine is positioned - if it's on an uneven surface, this could cause certain components to rattle around. Loose screws might also increase the noise levels.

Cleaning your dehumidifier's filter can make a difference to noise levels as, over time, dirt and dust can gather inside the machine. In extreme cases, the compressor or fan motor might need replacing entirely.

If you think the issue with your dehumidifier is related to an internal component, you're probably better off contacting the manufacturer for advice.

How to fix a dehumidifier that frosts up

A small number (2%) of participants in our survey told us that their machine had frosted up. Most refrigerant models should come with 'frost watch' technology that should prevent this happening (desiccant models don't need it, because of the different way they work).

However, your machine might freeze up if you've been running the dehumidifier in very low temperatures and then higher temperatures again. Increasing the temperature of the room and cleaning the coils with a soft cloth should fix this.

Go for a desiccant model if you know you want to run it in cooler conditions, or in a range of conditions, as refrigerants are only really suitable for rooms that are generally heated.

How to fix a leaky dehumidifier

When asked about their dehumidifier troubles, 10% of owners told us they were dealing with leaks: 5% from the water tank, 5% from elsewhere.

This is a problem because aside from the eye-rolling irony of a machine designed to draw in water leaking it out, liquid can damage carpets, and wooden and lino flooring.

If you've got your dehumidifier set up for continuous drainage, check that the connection to the drain hose is tight. The drain hose needs to be free of kinks and blockages, too, so remove it and flush water through it.

A leaky dehumidifier might also have a faulty component, and so has stopped recognising that it's going to overflow. If your dehumidifier is a refrigerant model, it might also leak refrigerant fluid. This isn't something you'll be able to fix yourself - you'll need a professional to take a closer look.

Dehumidifier doesn't collect water

Depending on the circumstances, this might not be a bad thing.

Once a (good) dehumidifier has managed to get the air in your room down to the desired level of relative humidity, it will stop operating. You wouldn't want it to keep drying the air to the point that it felt uncomfortable and your skin became dry and flaky. Your machine should spring back into action once the relative humidity rises.

If you've invested in a good dehumidifier, it might achieve your target level of relative humidity sooner than you were expecting, which might make you think it's not doing its job.

A dehumidifier should turn itself off once the water tank is full so that it doesn't overflow. It should start up again once you've emptied and refitted the tank, assuming you've refitted the tank correctly.

If your dehumidifier doesn't collect water, it could alternatively be because you're operatingit at too low a temperature (for refrigerants). Refrigerant dehumidifiers are much more effective at higher temperatures than lower ones.

Or it could be that you've picked too small a dehumidifier for your home. As a general rule of thumb, the bigger your property and the more of you living there generating moisture through activities such as washing clothes, showering and cooking, the bigger the dehumidifier you'll need. If you're spending much more time at home these days than pre-pandemic, your requirements might have changed.

Find out more about how a dehumidifier works.

How to use and maintain your dehumidifier

To keep your dehumidifier running longer and at its most effective, have a read through our top tips below:

  • Empty your dehumidifier regularly You'll definitely want to empty it before putting it away for storage. Wipe the tank with a cloth. Water that has been left to stagnate can develop mould and mildew.
  • Try to position your dehumidifier in the centre of the room Don't position the machine right next to walls, curtains or furniture.
  • Keep windows closed, but internal doors open Damp air migrates towards a dry spot to create a balanced humidity across the entire space, so you should leave doors within your home open for air to circulate, but close your windows so that damp air outside isn't attracted to come in to a drier space indoors. Leave bathroom windows open for 15 minutes after a bath or shower, though.
  • Protect your items Check with a specialist what humidity setting you need if you're going to be using the dehumidifier in a room containing valuable items. Note that for general use, a relative humidity of 30% to 50% is ideal.

We've surveyed owners of dehumidifiers from Ebac, Ecoair, DeLonghi, Dimplex and Meaco to find out which brands are more likely to develop faults - find out which dehumidifer brands are most reliable. Or head straight to our independent dehumidifier reviews to see all the models we've tested.