Dehumidifers - A Guide to the Different Types


There are three main types of dehumidifier technology, choosing the right one for your home is important to ensure you get the best results. Each type of dehumidifier has different pros and cons, this guide to dehumidifier types will explain the different technologies used and help you decide which one will be most effective.


Normally found on larger units a compressor dehumidifier works in a very similar way to a an air conditioner. A compressor compresses a working gas until it becomes a liquid, in the process it gets hot and is passed through a hot coil. The gas is then allowed to expand and as it does so it cools and passes through the cold coil. Air from the room is blown by a fan firstly over the cold coil where water from the air condenses and is collected in a bucket. The cool dry air is then reheated by passing it over the hot coil and then back into the room.

While these units are very effective and can remove large volumes of moisture form the air they do consume a fair amount of power. The biggest downside to these units is that they are noisy, although some modern units now use scroll type compressors which are quieter and more efficient.

Dessicant and Salt Based

These use a dessicant to absorb the moisture in the air. A dessicant is a substance that readily absorbs water, salt and silica gel are commonly used in dehumidifiers. Those using silica gel have the advantage that they can often be 'recharged' by heating them. The salt based ones will need topping up as the salt is slowly dissolved in the water. The big advantage of this type of dehumidifier is that they are completely silent when in use. The downside is that they are not suitable for dehumidifying large areas and you may need to keep topping up the salt or recharging the silica gel.


These dehumidifiers tend to be smaller units and use a peltier element to generate the cold side to condense water from the air. As this type do not have a compressor they tend to be very quiet in operation, normally the only noise you will hear is the fan that is used to move the air through the dehumidifier. The downside of these is that they are not very efficient in the amount of electricity they use, hence they are only used for smaller units where the running costs are not such an issue.