Informational Guide

Why Does My Dehumidifier Ice Up?

There are several reasons why dehumidifiers tend to ice up. Learn the things you can do at home to easily fix your dehumidifier.

by Josh M

When you want your home to stay mildew and mold-free, it’s frustrating when your dehumidifier simply stops working because the coils have frozen.

There are several reasons why a dehumidifier might ice up, and there are things you can do at home to fix your dehumidifier.

This guide will walk you through the possible reasons why dehumidifier ice up and what you can do about it.

Common Reasons Why Dehumidifiers Freeze Up

Room Temperature

The room temperature is one of the most common reasons why a dehumidifier can freeze up. Dehumidifiers need to be in rooms that have a room temperature of 60 degrees Fahrenheit or more. Anything lower than this amount will cause problems, and your dehumidifier may freeze up.

When the dehumidifier freezes up, it can no longer draw in moisture from the air.

Blocked Air Flow

Blocked air flow can cause dehumidifiers to freeze up because the air isn’t moving over the coils fast enough. Without fast moving air over the coils, the coils can freeze. You can look for blocked airflow in your dehumidifier by checking the rate that air moves through the unit.

When you put the unit on high, does the air that comes out of the unit remain thin and limited rather than forceful? That’s a problem and most likely related to blocked airflow. The best way to fix this problem is to replace the fan inside the dehumidifier.

Lack Of Cleaning & Maintenance

Another common problem is the lack of cleaning and maintenance with dehumidifiers. We recommend cleaning your dehumidifier once a month at a minimum. This includes removing the largest pieces and cleaning the interior of the machine.

Make sure that the coils do not have ice, and make sure that the fan is not blocked. Remove all dust with a warm washcloth and fully clean the tank with an antibacterial cloth (think Chlorox or Lysol).

Sensor Failure/Faulty Coils

If the sensor fails, your dehumidifier will ice up. The reason for this is because the humidity sensor inside of your machine is what determines how much relative humidity is in the air.

If the sensor does not accurately report that the relative humidity levels have lessened, then the machine may run longer and keep coils cold. If coils remain cold for too long, this often leads to ice.

Dehumidifier Water Reservoir Plug

What Will Happen When They Freeze Up? (Main Parts Affected)

Fan Motor

The fan motor is a sensitive electrical component that should not be near water or ice. If you do not thaw your dehumidifier quickly, the ice may accumulate and eventually make its way to the fan motor. If the fan motor is surrounded by ice or touching ice, then it may cease working altogether.

Blower Wheel & Fan Blade

If your appliance is freezing up, you may notice that the blower wheel and fan blade are not working correctly. Sometimes the ice negatively affects the blower wheel and causes damage by latching onto it. In addition, the fan blade may become torn. You may also notice that no air is coming from your dehumidifier because the ice is in the way.

Humidity Management System

When the dehumidifier is frozen, the humidity management system will no longer work. This system includes the sensor that determines how often the dehumidifier should run and at what speed.

When the dehumidifier isn’t working, mold and mildew spores can grow and begin to take over your home. This system can be permanently damaged if your dehumidifier frequently freezes.

How Dehumidifier Works_Wide

How To Fix a Dehumidifier That Has Iced Up Already?

If your dehumidifier has already iced up, then you need to take action to thaw it out and restore it to its working condition. The first step is to empty the tank. You want to make sure that no excess water remains.

The second step is to unplug the dehumidifier and move it to a higher position (on top of a table or other piece of furniture). Higher positions tend to have warmer air, and that will help thaw out the appliance.

The third step is to remove the filter, clean it, and allow any ice attached to the filter to melt off. This may take several hours. From here, check the fan and make sure that the airflow is not blocked or restricted in any way. Check for any excess debris in the unit and make sure to remove all of it.

The fourth step is to turn your heat on in your home to ensure that the temperature is at least 74-75 degrees. Let your dehumidifier thaw out by allowing the ice to melt. This will take approximately 12-24 hours. Make sure the ice has completely melted before moving on to the final step.

The final step is to wipe all excess water off of the dehumidifier and put each piece back together. Turn on your unit. It should be working properly now.

Preventing The Dehumidifier to Freeze Up (Tips and Tricks)

TECCPO Dehumidifier Sample Product

It is easier to prevent your dehumidifier from freezing up than it is to deal with a frozen dehumidifier. In order to keep your dehumidifier from freezing up, we recommend following these tips and tricks.

Try keeping your dehumidifier on a raised surface. The higher up your dehumidifier is, the warmer the air will be. Another tip is to cycle the dehumidifier. This means running your unit in cycles that alternate.

For example, you can run your dehumidifier in a 3-2 cycle, which would be 3 hours on and 3 hours off. It’s best not to let your dehumidifier run beyond 3 hours at a time so that the coils won’t have enough time to freeze.

Our final tip is to make sure that you are thoroughly cleaning your unit. Most dehumidifiers ice up faster if they are not maintained with cleaning. The more debris in your unit, the more likely it is to ice up completely. Make sure that you clean the internal components every two weeks to avoid anything icing up.

People Also Ask (FAQ)

Can I leave a dehumidifier on all the time?

Yes, you can leave a dehumidifier on 24/7. Most dehumidifiers are designed to run around the clock. However, your dehumidifier will stop running once the tank fills up. You need to make sure that you can regularly empty your dehumidifier if you plan to run your dehumidifier 24/7.

How does auto defrost work on a dehumidifier?

Auto defrost is a setting that interacts with a sensor inside of your dehumidifier. Not every dehumidifier has this setting, but when they do, it is convenient. Once the sensor senses ice, it will turn off the compressor system within your dehumidifier. The fan typically stays on so that the room temperature air can help thaw the compressor.

Do dehumidifiers work in very cold temperatures?

Dehumidifiers can work in rooms that are cooler, but they should not be placed in spaces that will be below 60 degrees Fahrenheit. Any temperature lower than 60 degrees can create problems by icing the coils inside of the dehumidifier.

What should I set my dehumidifier to in the winter?

Winters tend to be drier than summers. You can set your dehumidifier a bit higher during the winter months, around 45-50%. During the summer months, we recommend setting your dehumidifier lower around 35-40%.

Do dehumidifiers work better in hot or cold rooms?

Dehumidifiers work best in hot rooms because they use cold coils to help condense the moisture from the air. However, as long as the room is above 60 degrees Fahrenheit, it should be fine and can be used.


After exhausting all repair options, your dehumidifier is hopefully now working. If not, you may need to bring in a professional HVAC maintenance specialist or purchase a new appliance. Most dehumidifiers last five to ten years. Older dehumidifiers that ice up repeatedly are best replaced.

Last Updated on January 12, 2023

Josh M

My name is Josh and I am obsessed with the HVAC industry. I created this website to help HVAC techs of all levels get the best out of their heating & cooling systems. I have spent thousands of hours studying air conditioners, heaters and home air products so you can learn & buy with confidence. Learn more about the team here.