What Is The Difference Between Desiccant and Refrigerant (Mechanical) Dehumidification?

19 Aug 2021

Dehumidifiers remove moisture from the air. There are two main types of dehumidifier technology that do this: Desiccant and Mechanical (refrigerator coil technology). Which should you choose?

Desiccant Dehumidifiers:

Desiccant dehumidification works by passing air through a rotating desiccant wheel to exact moisture from the air. Desiccants such as silica gel naturally absorb moisture - that's why you'll find little packets of silica gel in new shoes or electronic goods. As the wheel rotates, a small portion of the rotor is used to reactivate the wheel. In this portion, the desiccant is heated so the moisture is released and is then ducted out from the dehumidified space. 

Mechanical (Refrigerant) Dehumidifiers:

In comparison, mechanical dehumidifiers work in a similar way to a refrigerator. They usually work by drawing moist air over a refrigerated coil with a fan. The cold evaporator coil of the refrigeration device condenses the water, which is removed, and then the air is reheated by the condenser coil. The now dehumidified, warm air is released into the room. 

Comparing Performance:

The main benefit of a desiccant dehumidifier is that it performs exceptionally well when used in cooler temperatures, or when a low dew point is required. As there is no actual water produced during the process, these units can work effectively at sub-zero temperatures. 

In comparison, Mechanical (refrigerant) type units are more economical at higher temperatures i.e. 30 degrees C. They are also particularly useful in the early stage of flood restorations. 

What Type of Dehumidifier do You Need?

Depending on the application, size of the space, specific function and a variety of other factors - will determine what technology you require.  Sometimes you may need more than one technology.  For example, a pharmaceutical manufacturer may need a desiccant dehumidifier and an air conditioner.