What Causes a Dehumidifier to Freeze Up and How to Fix This

Dehumidifiers are great when you live in a high humidity zone, these little household appliances remove the excess moisture so you do not feel the heat. They keep you and your family comfortable all day and night.

However, these units may freeze up on you and end that comfort zone you enjoy. When that happens you need to defrost your dehumidifier and to find out how to do that, simply keep reading our article.

Why Do Dehumidifiers Freeze Up?

There are two main reasons why your dehumidifier will freeze up:

1. Low room temperature: the basic principle of how a dehumidifier works is that air flows through the unit, as it does the cold coils cool the water so that it will condense and drop into the water collection tank. Or it is pumped to a drain continuously.

However, when the temperature of the room gets too low, then that water vapor freezes and clogs up the system. When that happens your dehumidifier stops working.

2. Air flow: There are different situations where the normal air flow is hindered. The fan could not be working that well and the air flow slows down too much. When that happens you should turn the unit off or you could damage the coils.

Make sure to unplug the dehumidifier and then open it up to see what maintenance should be done.

What Causes a Dehumidifier to Freeze Up?

There are several causes that could create this situation. Here are a few of them and how to fix the issues:

1. Blower wheel or fan blade

If you see that your dehumidifier is freezing up, but the room is still over 65 degrees F then there may be a problem with the blower wheel or fan blade. To fix this problem, you need to remove the fab cover and inspect the blades or the wheel.

First, clean the blades, etc., then look for any debris that may be causing them not to turn and remove that debris. Next, if you see the blades are damaged you will have to replace those blades.

2. Humidity controls

The same scenario will be evident here as it is with the fan blades. The room’s temperature is over 65 degrees F but your dehumidifier is freezing up. That makes it hard to diagnosis the source of the problem.

If you have inspected the fan blades, etc., and there is no problem with them, move on to the humidistat or humidity control. There may be a problem with the electrical contacts causing the condenser to remain on when it shouldn’t.

That keeps the dehumidifier’s temperature too low and it will freeze up on you. You can test the control using a multi meter or shut the power off and turn the control’s dial.

As you turn the dial, the contacts should show an open circuit. If it doesn’t, then you need to replace it.

3. Fan Motor

This is the third source to check if the other two are in top working condition. If the fan is bad, then you should not feel a lot of air flow through the grill. Clean the grill, the wheel and the blades first before moving on to testing the motor.

After that, remove the fan motor and look for damage. If there is none, clean the motor and put it back. Then turn the dehumidifier to fan only and test it out. If there is still no air flow, you will have to replace the motor.

Why Does My Dehumidifier Freeze Up?

The three previous sources are the most common situations you will run into. There are other possible sources that would contribute to this problem and here is a list of a few of them:

  • Defrost sensor malfunctioned - this is a good possibility as the wiring may come loose or something corrupted the sensor. When this happens your unit will freeze up and you may have to repair or replace the sensor
  • Dirty parts - the evaporator coil or condenser may have gotten dirty on you. That is why regular cleaning is necessary. It keeps dirt, dust, mold from interfering with the unit’s operation
  • Faulty parts - if you work your dehumidifier more than usual, then parts can break down and stop working. Have a qualified repairman handle this fix.
why does my dehumidifier freeze up

How to Defrost Dehumidifier

For many standalone units, they come equipped with an anti-defrost or automatic deicing function. If the sensor is working properly, then the unit will defrost itself and you shouldn’t have to do any work.

If the sensor is bad and does not turn those features on, you may have to replace the sensor. If there is ice buildup, turn the unit off and let it warm up to get all the ice off the coils, condenser and other parts.

Once the condenser coils, and the refrigeration system warm up, you can take it apart and inspect those elements we have already mentioned above. Test the electronic control, examine the fan blades, blower wheel and so on.

Clean them up if needed and don’t forget to clean the filters. Also, replace any damaged or broken parts. Once you have done all of this, your dehumidifier should return to working like normal.

Final Verdict


As you can see this situation is not the end of the dehumidifier. You can repair it or have it repaired and it will continue to provide you with top service. The anti-defrost dehumidifier may take a qualified repairman to handle.

Just take this situation step by step so you do not do more work or spend more money than you have to.

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