Why Does My Dehumidifier Freeze Up?

Dehumidifiers remove moisture from the air in your home or office.


Due to the way the human body experiences heat, this gives the subjective experience of a room being cooler than it is, making them a great way to limit air conditioning bills. But, used improperly, ice will build up in the machine.

Dehumidifiers take advantage of the phenomenon of condensation. Condensation occurs whenever a cold surface comes into contact with warmer, humid air. Some of the moisture in the air reverts to its liquid state and collects on the cold surface.

Example of Condensation

The most common example of condensation from everyday life is the buildup of water at the bottom of a glass of iced soda. The cold surface of the glass touches the hot, humid air around it, and some of the moisture from the air collects on the outside of the glass.

How Dehumidifiers Dehumidify

Inside the dehumidifier is a condenser coil. All the heat is pulled from the condenser coil, making it very cold. As the hot, humid air is pulled over the coil, some of its moisture condenses on the coil and drips into the bucket. The air leaves the dehumidifier with less moisture than it had before.


Since the coil must be colder than the air around it for the condensation to occur, the dehumidifier will ice over at surprisingly high temperatures. EnergyStar states that most residential dehumidifiers will begin to ice over if the ambient temperature drops below 65 degrees Fahrenheit.

Cold-Air Dehumidifiers

Dehumidifiers designed to work in temperatures as low as 42 degrees are available. If dehumidifier freezing is a regular problem for your home, you may wish to invest in one of those models.

About the Author

Kevin Walker is a computer programmer who decided to take a few years out from the corporate life and see the world. He spent a total of six years living abroad and teaching English in China, Korea and Mexico before returning to his home in Texas. He uses his programming and teaching experience to write easy-to-understand computer tutorials.