Why Does My Dehumidifier Freeze Up?

Digital Hygrometer

Whether you live in humid climates like Arizona or just want to protect your valuable possessions, a dehumidifier is an essential part of many houses. Unfortunately for those who own them, problems can be frequent because of how often they’re used.

One common question that owners ask themselves is “why does my dehumidifier freeze up?”

We’ll be answering this question in this guide.

Defrost Sensor Failure

Dehumidifiers are getting more advanced by the day, with new features being introduced all the time. One of the newest additions to dehumidifier technology is a defrost sensor that detects frost or ice accumulation to protect your unit from fire hazard caused by malfunctioning parts.

Once frost is detected, power is cut. This allows the ice to melt before operation is resumed.

Unfortunately, if this feature fails, your dehumidifier will keep running as it won’t be able to detect the frost or ice on the coils. This leads to the dehumidifier overheating which could cause permanent damage.

Climate and Temperature

The most important thing to know about dehumidifiers is that they work best in warm temperatures. Warm air contains more moisture and this heat will prevent evaporator coils from freezing.

A temperature of around 65°F or above is best for a dehumidifier. Otherwise, water can freeze on coil coils before it has a chance to drain into the water tank.

This frost will accumulate on the coils and blades of your dehumidifier.

Dehumidifiers freezing up is a common problem in garages and basements because they are often unheated.

Some dehumidifiers come with a built-in thermostat that tells you the temperature in the room, while others don’t.

If maintaining the correct temperature is an issue, your heating or air conditioning should be used.

Poor Maintenance

Cleaning and maintaining your dehumidifier are an efficient way of having it work longer, work better, and saving you money on energy bills. You should clean it thoroughly every 2 or weeks.

Warm soapy water or vinegar will do.

The other two components which need to be maintained to prevent freezing are the filters and coils.


You need to remove the filter and remove all dirt and dust with a vacuum cleaner or brush. You then need to wash them with warm soapy water.

This will remove all the bacteria and grime that accumulates over time. This is important as dirty filters restrict airflow. This restricted airflow causes the coils to freeze.


The dehumidifier coils are not easy to clean, but it is necessary. Unplug the dehumidifier before removing the case.

You will need to use a damp cloth to remove the dirt from the coils. This will ensure moisture can evaporate properly, preventing the coils from freezing.

Faulty Parts

There are other important parts other than the filters and coils. If your dehumidifier is refrigerant-based it will also have a fan which helps circulate air and an electric motor that powers it.

If any of these components break down or fail for any reason, they may cause the machine to freeze; this can happen when there isn't enough airflow into the dehumidifier, leading to coil freeze.

It’s important to clean the fan blades and check on refrigerant liquid levels as these are common causes of dehumidifier freeze. If using a desiccant dehumidifier, this will be less of a problem as there is no fan, compressor or refrigerant.

Final Verdict

The key to preventing dehumidifier freeze is proper use and maintenance.

A dehumidifier that freezes is a potential fire hazard, so always monitor it when in use and make sure that the ambient temperature is suitable.

About the Author Lets Remove Mold

If you're looking to buy a new dehumidifier then you're in the right place. Through years of HVAC and mold remediation experience, the team at letsremovemold.com are able to provide advice on the type of dehumidifier you need for your home.

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