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Which Type of Dehumidifier do I Need ?

Date posted: 13 December 2016

The two main types of dehumidifier – desiccant and refrigerant – both work to remove moisture from the air, helping you to control the relative humidity in a room.

Each type uses a different type of technology to achieve this, however. Before you invest in a dehumidifier you will need to understand the difference between the two, and work out which is best suited to your specific circumstances.

Refrigerant dehumidifiers

Refrigerant units condense moisture out of the air. They draw in damp air from the room and pass this over a cold evaporator coil, which cools down the air to below its dewpoint temperature. This causes it to condense, at which point it can be collected from the cold coils into a collection tank.

The water collection container may be removed and emptied manually, or in other cases the dehumidifier has a hose attached to it through which the water is automatically disposed of. Meanwhile, the dried air in the machine passes over warm condensing coils, heating it again before it is released at pressure from the machine, so it can be directed towards specific damp areas to speed up the drying process.

Desiccant dehumidifiers

Desiccant  models work by passing air through a rotor containing moisture adsorbent desiccant material (e.g. silica gel), which removes water from the air. The dry air is then blown back into the room, accelerating drying of any damp areas. The water that is collected within the desiccant rotor is removed by adding heat, so the vaporised moisture can then be ducted out of the room. This leaves the desiccant wheel ready to collect more moisture.

Analysing the performance of the two types :

Moisture extraction rates

Refrigerant dehumidifiers can extract a larger volume of moisture each day when compared with desiccant units, which makes them ideal for use in the early stages of flood restoration work when saturated materials need to be dried out rapidly.

That said, however, it is important to compare models of dehumidifiers because the extraction rates vary depending on the specific make and model. Manufacturers should provide details of each model's extraction rate to help you make an informed decision when hiring or buying a dehumidifier.

Ideal operating conditions

One of the significant differences between refrigerant and desiccant technologies is their performance abilities at lower temperatures. 

Desiccant dehumidifiers can operate effectively in cold temperature conditions because the desiccant material still absorbs moisture regardless of temperature. Refrigerant dehumidifiers, on the other hand, extract moisture far less effectively when operating at colder temperatures, because the dew point is more difficult to reach, and therefore condensation of moisture out of the cold air is hard to achieve.

Cost of running

Overall, refrigerant dehumidifiers use less electricity than desiccant models, so work out cheaper to run. Look for the energy rating on any dehumidifier you are considering purchasing, then you will be able to calculate how much it will cost you to run. 

Noise levels

Refrigerant dehumidifiers uses compressors which generally make them louder than desiccant units.

Machine size, weight and portability

Refrigerant dehumidifiers are usually heavier than desiccant models because they incorporate heavier components, and they are also often larger in size. If they are fitted with sturdy wheels, however, they should still be easy enough to move around – but if you need to move up or downstairs this could be a consideration.

Where to get the right dehumidifier for my job

At Best at hire, we offer a wide range of dehumidifiers for hire suitable for both domestic households and professional contractors working on large building projects.We also offer a delivery and collection service to anywhere in mainland UK from one of our 70 UK depots. 



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