If the combination of last week’s heatwave and the weekend’s showers have left your home horribly humid, you may have found yourself dragging the dehumidifier out of the cupboard.
Dehumidifiers draw moisture from the air to reduce humidity levels in your home, which will make you feel cooler and less sticky.
But given your dehumidifier’s probably not been used since earlier in the year, you might have found – like the people below – that it’s suddenly stopped working.
We’ve surveyed 570 owners of dehumidifiers made by leading UK manufacturers to find the most common problems (and how you can fix them).
Or if you’re looking to buy a dehumidifier, we recommend the brands to consider and avoid.
Common dehumidifier problems and how to fix or avoid them
Start by turning off the power and disconnecting your dehumidifier.
And check the manual to make sure that the information we’ve given here is suitable for your model: inappropriate DIY repairs could invalidate your warranty.
Nearly 20% of those whose dehumidifier had broken down told us that it had leaked, with some people encountering leaking from the tank, and some from the unit itself. That’s a problem because (aside from the irony of a machine that’s meant to draw in water leaking it back out again), water can damage carpets, and wooden and lino flooring.
If you’re among this unlucky 20%, there are a couple of things you can check for.
If you’ve got it set up for continuous drainage, check your collection bucket is positioned properly and that it doesn’t have any cracks.
Also check that the connection to the drain hose is tight, that the drain hose has no kinks or bends, and that it’s not blocked (remove it and flush water through it).
Another reason could be that the dehumidifier has a faulty component, and so has stopped recognising that it’s going to overflow. This isn’t something you’ll be able to fix yourself.
If it’s a refrigerant model, it may also leak refrigerant fluid. Contact a professional if you think that’s the case.
Other possible reasons for a refrigerant dehumidifier leaking include the coils in the unit icing over and then the ice melting. This could happen if you’ve been running it 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.
Choose a machine with frost watch to avoid this, or go for a desiccant model if you know you want to run it in cooler conditions.
10% of participants in our survey told us that their machine had frosted up.
Humidistat or auto function has stopped working
This is another problem that dehumidifiers sometimes fall victim to.
The majority of dehumidifiers have an auto setting for measuring relative humidity. If that’s faulty, the dehumidifier won’t have the right information to adjust itself to the conditions in your room, and so may stop working prematurely.
If that’s the case, you’ll need to call the manufacturer or a professional.
Dehumidifier isn’t collecting much or any water
Depending on the circumstances, this might not be a bad thing.
Once a 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 it’s a good dehumidifier it may achieve your target relative humidity sooner than you were expecting, which may make you think it’s not doing it’s 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.
Another explanation might be that you’ve been operating your dehumidifier at too low a temperature (for refrigerants). As we mentioned before, refrigerant dehumidifiers are more effective at higher temperatures.
Not sure why your dehumidifier isn’t working
The greatest number of people – four in ten – told us that their dehumidifier had simply stopped working.
While it’s impossible for us to diagnose why that might be, below we’ve compiled some tips on using your dehumidifier properly to help you get the most out of it and keep it in peak condition for longer.
How does a dehumidifier work?
The two main types of dehumidifier are refrigerant (aka ‘compressor’ dehumidifiers) and desiccant. Here’s how they work in a nutshell:
They draw the air in and pass it through a filter and over cold coils, using similar technology to a fridge. Water condenses and drips into a tank. The dehumidifier blows the dry air back out.
These are the more popular choice for occupied homes in Britain. The higher the temperature, the more effective a refrigerant dehumidifier will be.
These use an adsorbent material to extract water from the air. The material is heated and the water is squeezed out into a tank.
Desiccant dehumidifiers often work more effectively in lower temperatures (garages or conservatories, for example) than refrigerants, although our tests have found some of each type that work very well in both conditions.
Find out more about how a dehumidifier works.
How to use a dehumidifier properly
- Empty your dehumidifier regularly, and definitely 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.
- Position your dehumidifier in the centre of the room, if you can. Don’t position it 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 fifteen minutes after a bath or shower, though.
- Check with a specialist what humidity setting you need if you’re going to be using it in a room containing valuable items such as guitars. For general use, a relative humidity of 30% to 50% is ideal.
Head straight to our independent dehumidifier reviews to see all the models we’ve tested.