How Does a Dehumidifier Work

how do dehumidifiers work
The awesome Meaco DD8L Desiccant Dehumidifier

If you are thinking of buying a dehumidifier you might have questions such as ‘how does a dehumidifier work?’ or ‘what does a dehumidifier do?’ Read on for a detailed answer.

The average family creates around 12 litres of water per day in their home through activities such as having showers, cooking, washing up and even breathing!

While you might not notice it, especially when the central heating is on, water is all around us. While this is somewhat healthy you don’t want excess water in the air. The ideal relative humidity level for a home is around 50-60% (You can check the humidity level of your home with a hygrometer).

If the air in your home is too wet then you may want to invest in a dehumidifier in order to live a healthier live.

Control Panel

Full size dehumidifiers feature a control panel on which there is a ‘on’/’off’ switch as well as a dial for different settings.

Typically a dehumidifier’s settings range from low to high and, for better models, also feature a ‘Laundry’ or ‘Turbo’ mode which sets the dehumidifier to run continuously, at high power, no matter what the relative humidity level is in the room. As the name implies the ‘Laundry’ setting is ideal for drying clothes inside as it intercepts moisture before condensation hits the windows.

The best dehumidifiers have a digital panel which shows the exact humidity level in your house.

Dehumidifier Types

The two main types of dehumidifier are compressor dehumidifiers and desiccant dehumidifiers.

Compressor dehumidifiers, like air conditioners and refrigerators, work by refrigeration whilst desiccant dehumidifiers work by absorption.

Compressor Dehumidifiers

how does a dehumidifier work
The excellent Ebac 2650e Compressor Dehumidifier with hydrophilic coated coils

A compressor dehumidifier works by pulling air into the dehumidifier via an electric fan.

This warm air is then passes over cold coils which contain a coolant which is circulated by a pump and a compressor. The cooled air losses its moisture which falls down into the water tank below.

The cool air is then passed over a warm coil which heats the air back up to its original temperature or more before it is pushed back into the room.

While this process is simple there are several important notes:

  • The fan and compressor make compressor dehumidifiers louder than desiccant types
  • Generally when compressor dehumidifiers push warm air back into the room the air is of a lower temperature than that of most desiccant dehumidifiers (the Meaco DD8L Desiccant Dehumidifier is an obvious exception as this dehumidifier heats the surrounding air temperature by 10C-12C).
  • Compressor dehumidifiers produce greenhouse gases thus are not eco-friendly

Also the best compressor dehumidifiers, such as the Ebac 2650e Dehumidifier, use hydrophilic coils. This means that the coils are coated with a substance that allows the moisture to run of the coils at a higher rate. Therefore this type of dehumidifier is more efficient than other compressor models.

Desiccant Dehumidifiers

As the name implies desiccant dehumidifiers make use of a ‘desiccant’ which is a substance that is water absorbent.

A fan pushes the air to the rotor which contains the desiccant. The desiccant absorbs the moisture as a second fan pushes hot air, heated by a heating element, into the rotor to extract the moisture from the desiccant.

The moisture then falls into the water container below as the warm air is pushed out of the dehumidifier into the room.

Important Differences

How do dehumidifiers work
The superb EcoAir DD122MK5 Desiccant Dehumidifier

Because there is no compressor desiccant dehumidifiers are generally lighter and quieter than compressor dehumidifiers.

Compressor dehumidifiers are best used in warmer temperatures. Bear in mind that the average testing environment for dehumidifiers is a temperature of around 30C and a relative humidity level of 80%. If only we’d get those temperatures here!

Therefore, when it comes to choosing a compressor vs desiccant dehumidifier in the British Isles the desiccant dehumidifier wins hands down.

This is because desiccant dehumidifiers:

  • Are generally quieter
  • Are generally lighter
  • Have better extraction rates at lower temperatures
  • Are cheaper to run at lower temperatures
  • Have a constant extraction rate no matter what temperature
  • Are Eco-Friendly

My Recommendation

There are many great desiccant dehumidifiers on the market including the EcoAir DD122 MK5 Desiccant Dehumidifier  which features an ioniser and silver nano filter which is great for those suffering from allergies and asthma.

However I personally own a Meaco DD8L Desiccant Dehumidifier and I can’t recommend it highly enough!

For more information you can read about the differences between the Meaco DD8L and Meaco DD8L Junior, our review of the Meaco DD8L and other Meaco DD8L articles on this blog.

You could also read more about the Meaco DD8L on Amazon including reviews of the Meaco DD8L.

As always if you have any questions feel free to contact me at byemould at gmail dot com (no spaces).