7 mistakes everyone makes with dehumidifiers

From buying the wrong size to not cleaning the filter, here what you should and shouldn’t do with your dehumidifier

A closeup of an Ecoair dehumidifier sitting in a living room
(Image credit: Ecoair)

Having the best dehumidifier in your house is incredibly handy, especially for autumn and winter. Not only do they remove moisture from your home and combat mould and damp, but they can also be used to dry your clothes when the cost of running your tumble dryer is just too high.

All these benefits and more are why you need to have a dehumidifier in your home. But if you’re making these common mistakes, you can affect its output, efficiency and cause it to break much quicker than its life expectancy.

Here are seven mistakes everyone makes with dehumidifiers and how to fix them.

1. Buying the wrong dehumidifier

Yes, there is such a thing as the wrong dehumidifier! There are actually three different types of dehumidifiers: refrigerant, desiccant and whole house.

Refrigerant dehumidifiers create a cold surface that’s colder than the air around them and draw air into and over the surface to condense moisture. This type is most effective at typical room temperatures. Desiccant dehumidifiers absorb moisture from the air using a desiccant material and operate best at lower temperatures. Finally, whole house dehumidifiers are large units that need to be installed and tend to sit in your loft and push air down into the home to remove damp.

Using the wrong dehumidifier can reduce its efficiency and double your costs so make sure you choose the right one for your home by asking the brand you’re shopping from what they recommend.

2. Choosing the wrong size

Having the wrong size can result in your dehumidifier not removing moisture from your home. If you have one that’s too small and it’s working in a large room, this can cause it to overwork and waste energy, while keeping your house in an moisture-filled state. But if you choose one that’s too large, it can be a waste of money as it’s not working to its full potential and you’re spending too much on it in terms of your monthly bills. Experts recommend a 10-12-litre dehumidifier if you have up to a three bedroom house but to choose a 20-25-litre model if your home is bigger or you have a lot of damp.

Best dehumidifier

(Image credit: Amazon)

3. Not putting your dehumidifier in the right place

It’s important to consider where you’re putting your dehumidifier, because yes, there is a right and wrong place to put it. Firstly, your dehumidifier shouldn’t be too close to a wall as this causes your device to overwork to pull in air which can damage it and run up your bills. Secondly, your dehumidifier should be away from doors, windows and air vents to avoid drafts and optimise its effectiveness.

The best place to put your dehumidifier is near the main cause of water, moisture or damp. Positioning it this way means it's closer to the issue and will solve the problem quicker. If your dehumidifier is for general use to improve your air quality, it’s recommended to place it in the hallway so it can cater to multiple areas.

4. Facing your dehumidifier the wrong way

This next mistake might sound silly but it does make a difference to how your dehumidifier performs and how well it dries your clothes. If you’re worried about the air being too intense, you might be tempted to turn it the other way so the air passes over it gently rather than full on. But this isn’t the most effective way to use your dehumidifier and means you spend more time and money waiting for your clothes to dry.

5. Keeping your windows and doors open while it’s in use

In general, your windows should be open to get fresh air into your house. But if you’re using a dehumidifier, this is one of the biggest mistakes you could make. Keeping your windows and doors closed while it’s in use means your dehumidifier isn’t working too hard drying out excess air which is coming from the outside. Instead, it’s working on the air in your home and can do a more productive job in an enclosed space.

woman trying to fix dehumidifer

(Image credit: iStock)

6. Not setting the right humidity level

Not setting your dehumidifier to the right humidity level is an easy mistake to make but it’s not particularly helpful for how the device performs. If the humidity level is too high, your dehumidifier will turn itself off too early when there’s still too much moisture in the air which can lead to damp problems. If it’s too low, your dehumidifier has to work harder to dry out the air and can make your home feel uncomfortable. According to experts, the optimal humidity level is between 30-50% to help your dehumidifier work properly and to avoid damp, bacteria and allergens.

7. Forgetting to empty and clean it

If you don’t regularly empty the water reservoir, change the filter and clean your dehumidifier, it can get extremely dirty and negatively affect the quality of your air. As dehumidifiers pull in air, it also pulls in bacteria and allergens which build up inside it if you don’t clean it properly. To avoid this, empty the water reservoir as soon as you see it reaching the maximum line so it doesn’t overflow. For the filter, clean it monthly and change it every few months to prolong the life of your dehumidifier. Finally, wipe over your dehumidifier with warm water and a cloth to remove any dust or dirt it might have collected.

Bethan Girdler-Maslen
Home Editor

Beth is Home Editor for T3, looking after style, living and wellness. From the comfiest mattresses to what strange things you can cook in an air fryer, Beth covers sleep, yoga, smart home, coffee machines, grooming tools, fragrances, gardening and much more. If it's something that goes in your house, chances are Beth knows about it and has the latest reviews and recommendations!


Having always been passionate about writing, she’s written for websites, newspapers and magazines on a variety of topics, from jewellery and culture, to food and telecoms. You can find her work across numerous sites, including Wedding Ideas Magazine, Health & Wellbeing, The Bristol Post, Fashion & Style Directory, TechRadar, CreativeBloq and more. In her spare time, Beth enjoys running, reading, baking and attempting craft projects that will probably end in disaster!