Why Does My Freezer Make Frost?

Aug 01, 2023, 17:32pm

One of the first instincts when you have frost in your freezer is to defrost it. A defrost is necessary every 6 months to defrost the evaporator. Depending on how you use your device, you may need to do this more often.

If, despite everything, frost forms on the wall of the freezer compartment, it will then be necessary to check and test certain elements likely to be responsible for this problem:

  • the door seal
  • defrost resistance
  • thermal safety
  • the temperature probe

If you’ve ever opened your freezer to find a frosty, icy scene, you might wonder what’s causing this. There are several reasons why your freezer might be building up frost, and understanding them can help you prevent the problem and maintain your freezer properly.

Why Does My Freezer Make Frost?

What is Frost and Why Does it Form?

Frost is simply water vapor that has condensed and frozen on a surface. In your freezer, frost can form when warmer, moist air enters the freezer and comes into contact with the colder air inside. This can cause the moisture in the air to freeze and accumulate as frost.

1. Frequent or Prolonged Openings

Every time you open the freezer door, warm air enters. If the door is left open for an extended period, or if the door is opened frequently, more warm, humid air can enter the freezer. This can lead to a build-up of frost.

2. Poor Door Seal

The door seal (or gasket) of your freezer helps to keep the cold air in and the warm air out. If this seal is damaged or worn out, it can allow warm air to seep into the freezer, which can lead to frost formation.

3. Overpacking the Freezer

If you overfill your freezer, this can prevent air from circulating properly. This can lead to uneven cooling and result in frost build-up in certain areas.

4. Defrost System Issues

Many modern freezers have automatic defrost systems that help to prevent frost build-up. If there’s an issue with this system – for example, if the defrost heater, defrost thermostat, or defrost timer is faulty – this can lead to frost build-up.

5. Wet Items in the Freezer

If you place hot or warm food in the freezer, or if your food items are not properly sealed, this can introduce excess moisture into the freezer, which can result in frost.


The role of the thermal protection device is to cut off the heating of the defrost resistance in case of abnormal overheating. It is usually in contact with the evaporator.

  • Set the multimeter to the continuity function (an icon resembling sound waves).
  • Place your test probes on the thermal shield and make sure it is engaged. If you have a value, then it is pass-through and therefore does not need to be changed.

Why Does My Freezer Make Frost?


The temperature probe has a value corresponding to a certain temperature. If the sensor does not show the correct value, the compressor runs constantly and frost forms on the evaporator.

To test the sensor, you must use the multimeter in the kilo-ohm position and read the value.

  • Compare the found value with the value specified by the manufacturer at a certain temperature.
  • If the value is incorrect, the sensor must be replaced.

Preventing Frost Build-up

Knowing the causes of frost in your freezer, you can take steps to prevent it:

  1. Limit Door Openings: Try to limit how often you open the freezer door, and avoid leaving it open for longer than necessary.
  2. Check and Replace the Door Seal: If the seal is damaged or worn out, consider replacing it to ensure a tight seal.
  3. Properly Pack Your Freezer: Avoid overfilling your freezer. Allow enough space for air to circulate properly.
  4. Address Defrost System Issues: If you suspect an issue with your freezer’s defrost system, you may need to consult with a professional appliance repair service.
  5. Cool and Properly Seal Food Items: Let hot food cool before placing it in the freezer, and ensure all food items are properly sealed to prevent excess moisture.

Remember, regular maintenance and being mindful of how you use your freezer can help prevent frost build-up, extend the life of your freezer, and ensure it operates efficiently.