How a Dehumidifier Works

Dehumidifiers regulate humidity by removing excess moisture from the air, thereby creating living conditions that are inhospitable to dust mites, mold, and other allergenic organisms. But, how does a dehumidifier work? What is the mechanism that allows it to take moisture that's is in gas form, from the air, and remove it liquid water? While there are two primary methods or styles that allows dehumidifiers to remove moisture from the air, for this article, we're focusing on the most popular style - refrigerant based dehumidifiers. So how does a dehumidifier work? Read on to find out!


The mechanics behind a refrigerant-style dehumidifier are actually quiet simple. Notice how moisture forms on the outside of your cold glass of water on a hot day? That's condensation, and once you know that, understanding how a dehumidifier works becomes a lot easier.

Room dehumidifiers, like a TruDRY work much like air conditioners; warmer, moist air enters the dehumidifier and then crosses refrigerant cooled coils, causing the moisture in the air to condense on coils within the machine. Why?

Much like your glass of ice water, the coils are colder than the air immediately around them. As air cools, it's ability to hold and retain moisture drops, and when the air has more moisture than it can hold, it forms that familiar condensate. The condensate then collects in a drip pan or bucket for disposal while the now cooled air passes back over the dehumidifiers warm motor to that it is slightly reheated before being discharged back into the room. By being slightly warmed, the air exiting the dehumidifier is dry and warm - which means it will attract moisture like a magnet and maximize the dehumidifier's efficiency.

Air is drawn into the unit by a fan

  1. Air passes over a cold surface

  2. As the air is cooled, it's moisture condenses

  3. Water falls into the container

  4. Air is re-heated by the heat recovery system

  5. Air Passes back into room 2° Celsius warmer and considerably dryer

  6. Defrost system automatically de-ices unit as necessary

  7. Unit switches off automatically when container is full

  8. When the unit achieves the selected level of dryness it switches off automatically

That's all there is to it!

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