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Make Which? a preferred sourceWhy has my dehumidifier stopped working?
We reveal the five most common dehumidifier faults and explain how to fix them, as well as how to keep your dehumidifier working effectively
A dehumidifier is useful for drying clothes and reducing humidity in your home, and it can be a crucial appliance if you're dealing with a damp or mould problem. But if you plug the machine in and it's not working properly, what's your next move?
We rounded up five of the most common dehumidifier problems and explain whether it's something you can repair yourself, or if you'll need to call in a professional or contact the manufacturer.
Plus we share our top tips on how to use and maintain your dehumidifier properly to ensure it keeps in a good working condition.
Make sure you don't buy a dehumidifier that doesn't work well or is expensive to run. Compare the best dehumidifiers from our tough tests
How to fix a dehumidifier with a broken auto function or humidistat
Most dehumidifiers have a humidistat for measuring the humidity in your room so it can respond 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' below). But if the humidistat or auto function is genuinely faulty, your dehumidifier won't have the right information to adjust itself to the conditions in your room.
Unfortunately, for this one you'll need to contact the manufacturer or call in a professional to get it repaired.
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.
Some dehumidifiers are just noisier than others from the outset, as we highlight in our reviews. All dehumidifiers make some noise, usually running discreetly in the background; others are annoyingly loud, even on 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 to be replaced 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
Most refrigerant dehumidifiers 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 temperatures, or in a range of conditions, as refrigerants are only suitable for rooms that are generally heated.
How to fix a leaky dehumidifier
Aside from the eye-rolling irony of a machine designed to draw in water, it can also leak it out, and liquid can damage carpets, 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 that has caused it to stop 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 can 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 really 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 also 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 operating it 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 a dehumidifier that's too small 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.
5 tips for using your dehumidifier more effectively
To keep your dehumidifier running longer and at its most effective, have a read through our top tips below:
- Empty your dehumidifier regularly and clean the filter This will keep it in the best working condition. When it's not in use, wipe the tank with a cloth as water that has been left to stagnate can develop mould and mildew.
- Place your dehumidifier in the centre of the room Position it at least 20cm away from walls, curtains or furniture. Unless it's specially designed to be close to walls, such as those in the Meaco Arete One range.
- 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 space that's more dry indoors. Leave bathroom windows open for 15 minutes after a bath or shower, though.
- Take care when turning it off It's important to remember to turn your dehumidifier off using its control buttons, which will let its fan finish its natural cycle. Then feel free to turn off the appliance at the wall.
- Don't put it too close to wet laundry It will help to reduce drying time for your laundry, but don't let it get dripped on. If possible, position it so the air coming out of the dehumidifier is directed towards the clothes, providing a slight breeze that will further help speed up the drying process.
