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What are the Differences between Refrigerant and Desiccant Dehumidifiers?

Date posted: 5 December 2016

When you're choosing a portable dehumidifier for your home you will come across two main types: "refrigerant" and "desiccant". Both of these types work to remove moisture from the atmosphere – enabling you to control the relative humidity (RH) of the room and create a more comfortable living or working space.

The two types differ, however, in terms of the way in which they collect moisture from the air. Understanding the difference between them will help you to decide which one will best suit your specific needs. 

Refrigerant dehumidifiers

This type of dehumidifier works by taking in damp air from the room via a filter, before passing it over refrigerated (hydrophilic) evaporator coils and bringing the air below its dew point temperature. This causes the water to condense and drip from the coils into a collection tank. This is similar to how condensation forms on cold windows.

This type of dehumidifier is generally said to be best for rooms with higher temperatures and higher humidities.

Desiccant dehumidifiers

This type of dehumidifier works by using a “desiccant” or moisture-absorbing material such as silica gel to remove water from the air. 

These materials have a high affinity for absorbing water vapour. The majority of modern desiccant dehumidifiers use the desiccant material in a ’rotor’ form. Rotors are made from alternate layers of flat and corrugated sheets, each of which is impregnated with the active desiccant. This creates a large number of axial air channels that run parallel through the rotor's structure. As the room's air flows through these channels, moisture is shifted from the air to the desiccant.

Which dehumidifier will best suit your needs?

Each type of unit offers a number of unique advantages – with refrigerant dehumidifiers usually emerging as the winner for households wishing to control the humidity of a particular room. To summarise:

Refrigerant units

These are ideally suited to ambient temperatures above 5°C, and they often use only a third of the energy required by a desiccant dryer. Their performance usually declines in temperatures any cooler than this. Refrigerant dehumidifiers are placed within the room that requires dehumidification, and are often used in domestic homes -- as well as in industries such as building, construction, flood recovery, museums and storage units. With this type, once the relative humidity in the room is reduced to the required level (which is usually 45-50% for optimum comfort in domestic settings), the unit automatically switches itself into standby mode until it is required again - at which point it will switch itself on automatically. Most households choose the refrigerant type as this usually suits an occupied home environment best.

Desiccant units

Desiccant dehumidifiers are generally most effective where:

  • very low relative humidity is required;
  • work is being undertaken at very low temperatures;
  • a low dew point is vital; or where
  • the unit needs to be ducted into the area that needs drying.

They can usually remove greater quantities of moisture per hour, and can produce low levels of humidity, but they require larger power supplies and are therefore more expensive to run. They can operate at lower temperatures than refrigerant types, so are ideal for cold areas such as workshops and garages as well as areas where dry conditions are essential, such as pharmaceutical and petrochemical applications. 

Where can I get one ?

Should you require a dehumidifier for either short or longer term rental , then Best at hire has a wide range available to suit your needs. Please speak to one of our representatives to help advise you on which one you need. 

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