How compressor dehumidifiers remove moisture from the air

Compressor dehumidifiers are the legacy dehumidifiers that have been used since the 1960s. Here's how they dehumidify the air through condensation.

How compressor dehumidifiers remove moisture from the air

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Compressor dehumidifiers and desiccant dehumidifiers are the two most commonly used dehumidifiers in Australia. While desiccant dehumidifiers are rather new, compressor dehumidifiers have been used for decades since the early 1960s. They are known for being efficient in removing moisture from the air in warmer climates and for their low energy consumption.

Structure of a compressor dehumidifier

A compressor dehumidifier generally consists of a compressor, a long metal tube that coils up in the evaporator section and the condenser section, a fan, and a water tank. There is refrigerant flowing through the metal tube to cool down the tube at the evaporator section and to warm up the tube at the condenser section.

Refrigerants used in a dehumidifier

The first generation of refrigerants used were chlorofluorocarbons (CFCs), also known as greenhouse gases. These days, a safer and more environmental friendly option known as Hydrofluorocarbons (HFCs) is used instead.

Dehumidifying mechanism of a compressor dehumidifier

Humid air passes through the evaporator where moisture in the air condenses and drips into the water tank. This cold dry air is then passed through the condenser to return to room temperature.

Illustration of how compressor dehumidifiers work


  1. Humid air in the indoor environment is drawn into the compressor dehumidifier and passed through the evaporator.
  2. The moisture in the air touches the cold surface of the evaporator, causing it to condense into water and drip into the water tank. As a result, moisture is removed from the air.
  3. The cold dry air is then passed through the condenser which has a warm surface, warming it up before it is blown back into the indoor environment.

The cooling and warming processes within the dehumidifier

One of the main functions of the compressor is to evaporate and condense the refrigerant through pressure in order to create cold and warm surfaces respectively.

  1. The refrigerant is sucked into the compressor from the evaporator section where a low-pressure environment occurs, causing it to vaporise and absorb heat in the process. This creates a cold surface along the metal tube in the evaporator section of the dehumidifier.
  2. The refrigerant is then pushed out into the condenser section of the dehumidifier where a high-pressure environment occurs, causing it to condense and release heat in the process. This creates a warm surface along the metal tube in the condenser section of the dehumidifier.


As a temperature difference is required for the moisture in the air to condense within the evaporator section of the dehumidifier, compressor dehumidifiers work best in warmer climates. It is important to understand how compressor dehumidifiers work so that you can make better decisions in choosing a suitable dehumidifier for household use.

Disclaimer: The information provided in this article is for general reference only. Please seek advice from professionals according to your business’s needs.

Josephine Gan

Josephine Gan

As a customer service manager for more than 5 years now, Josephine has assisted numerous customers in purchasing the air treatment device that best fits their needs. From moisture damage issues to allergens in the air, she understands the indoor air quality issues most commonly faced by Australians and provides practical tips in resolving them.