Here, we answer the question, “How do dehumidifiers work?” so you can decide whether this is an appliance worth investing in.
Whether you're looking to stop condensation in your home, struggling with a damp problem, or – like so many of us right now – searching for ways to dry wet washing without running your tumble dryer, the best dehumidifiers might be able to help.
Whatever your reason for considering a dehumidifier, we’re here to explain the science behind them and how using one in your home could be the answer to all your excess moisture misery.
How do dehumidifiers work?
First things first, if you are thinking of buying a dehumidifier, it makes sense to look into exactly how they work and what they can be used for.
Although this is an appliance that often springs to mind for those looking at how to reduce humidity in a house, many people don't actually understand how it operates or the other benefits it can offer.
"The air in your home contains moisture. And you can add to this moisture by the things you do at home – cooking, showering, drying washing, and so on," says Chris Michael from Meaco.
"When warmer, moist air hits colder air, the moisture condenses into water. That is when you start to notice damp and mould in houses, sometimes on walls and windows, and sometimes, more worryingly, on soft furnishings and even your clothes.
"A dehumidifier removes moisture from the air – excess moisture that you do not want to condense and hang around your home. It helps to ease damp problems, gives you healthier air to breath and can even make your energy use more efficient."
Chris and his partner Michelle started Meaco in 1991. Meaco is now regarded internationally as a major player in the dehumidifier industry selling to 20+ countries throughout Europe, North America and South Africa.
How do different types of dehumidifier work?
To decide which type of dehumidifier will be best for you, familiarise yourself with desiccant vs compressor models:
Desiccant dehumidifiers
Wondering what a desiccant dehumidifier is? These models are perfect for colder areas of the house, such as garages and storerooms – basically spaces where there is little or no heating.
"The air is drawn in over a filter and passed over an absorbent material called Zeolite," says Chris Michael. "When the material is saturated, a heater in the dehumidifier blows warm dry air across the Zeolite and the moisture condenses into water which is then dropped into a collection tank. The warm air is then passed back out of the dehumidifier at a higher temperature than the air that was taken in, so this dehumidifier can also act as a gentle heater."
Capable of extracting up to nine litres of moisture at temperatures as low as 1°C, this is one of our testing team's favourite desiccant models.
Compressor dehumidifiers
If your aim is to prevent damp and help clothes dry quicker, a compressor dehumidifier is the model for you. They work best in areas with temperatures above 15˚C.
"This type of dehumidifier draws in the air but instead of using the absorbent Zeolite, compressors have a cold-coils system, like a fridge," says Chris Michael.
"These types of dehumidifiers are often also referred to as ‘refrigeration dehumidifiers’. They have two sets of coils, the first cools to create the condensation, which is collected into the water tank, the second warms the dry air back to just above room temperature. This helps to create the dry air needed to combat condensation, mould and damp problems."
With an ultra-quiet design and low energy consumption, we voted it as one of the best compressor dehumidifiers on the market after testing it.
Will a dehumidifier stop window condensation?
Dehumidifiers are a great way to prevent or reduce window condensation. How effective they are at doing this relies on choosing the right type and the size of the model.
Of course, opening the windows in a room will also help with condensation, but in the depths of winter, do you really want to bring freezing cold air gushing into your home?
As we have discussed, dehumidifiers remove excess moisture from the air – moisture that would otherwise be deposited on your windows as condensation. Place your dehumidifier close to the window for maximum effect.
Do dehumidifiers stop damp?
When it comes to what causes damp, there are several culprits. However, a damp problem that has been caused by poor ventilation and excess condensation can most certainly be helped by the use of a dehumidifier.
That said, if damp is a persistent issue, caused by other factors concerning the structure of your home, a different and more involved solution is going to be required long term.
"The permanent use of dehumidifiers is a poor substitute for efficient heating and adequate ventilation when it comes to dealing with damp," says Douglas Kent, a chartered building surveyor specialising in building conservation and the technical and research director at the Society for the Protection of Ancient Buildings (SPAB).
Douglas Kent is a chartered building surveyor specialising in building conservation and is technical and research director at the Society for the Protection of Ancient (SPAB), where he has worked since 2000.
If you've ever wondered where the water inside a dehumidifier comes from, Viktor Velikov, Director of Elserve, explains, "The water collected in the tank isn’t from the appliance itself but from the room’s air. This process removes humidity from the space, speeding up drying and helping to prevent damp and mould from developing."
There are endless benefits to owning one of these devices, but can you have too many dehumidifiers? Our expert guide has the answers you need.
