Why Does Dehumidifier Freeze Up And How To Fix It

On a bitterly cold winter, there are many things that will slow down or stop working completely. This includes your trusty dehumidifier that is critical in this is the situation. But wait, my particular model has an anti-defrost feature that should protect it from freezing up. And if I recall correctly, it should also have a low-temperature operation feature. So what could possibly cause the dehumidifier to ices up?

Super Cold Temperature

Most dehumidifiers freeze up because the room is simply too cold. Even if the machine has a low-temperature operation, it is typically cap at 65°F degrees. Running the dehumidifier below the recommended temperature will cause ice to build-up and water freeze on the condenser coils. The only saving grace is the auto-frost mode that will shut down the compressor when the coils become too cold.

Defrost Sensor Failure

A faulty sensor or wiring issue may cause the dehumidifier fail to recognize an imminent freeze up. This can lead to all sorts of damage to the internal components. Most standalone dehumidifiers have auto-defrost/ auto-deicing mode. It is a sensor-based feature that will disable the compressor from working when there is ice build-up detected. After a cool off period, the compressor will resume back to work once the ice on the coil has melted.

Evaporator Coils or Condenser Coils is Dirty

Overtime there is bound to be some deposits on the dehumidifier’s coil. From dust, mold, to germs, these microscopic particles will accumulate and occupy the coil. Without sufficient air passing through, the dehumidifier coils will freeze up causing the entire operation to malfunction. That’s why the washable filter plays a key role in extending the dehumidifier’s life expectancy. Some manufacturers will recommend cleaning the coil fins from time to time to reduce particle obstruction.

Poor Airflow Delivery

Disruptive airflow means there is reduced airflow from pushing into the refrigeration system. This could be due to a few common reasons. First, the dirty filter clogged with dust prevents air from going through. A fairly easy fix with a quick wash but many would neglect it. Next, air inlet or outlet blockage that impede air circulation. This usually happens when we place the dehumidifier too close to the wall or there are foreign objects above it. Lastly, the motor fan is not functioning properly thus limits the amount of cold air from pulling in.

Faulty Parts in The Refrigeration System

A single faulty part in the dehumidifier’s refrigeration would disrupt the whole operation. A defective motor fan, refrigerant leakage, burn compressor, or sensor failure means there is an impending ice build-up. Even simple electrical errors on the humidistats or control panel would stop the dehumidifier from working as it should.

There are many reasons why you shouldn't let a dehumidifier to freeze up. The main reason is the impact on life usage expectancy due to damaged parts. The motor and compressor will have to work harder to absorb the excess moisture. There will be more rattling noise or vibration as wear and tear parts are under constant stress. The dehumidification output will continue to dip as there is more blockage in the coils. Worse of all, there will be a surge on electricity bills as the operational hours will be longer from a poorer performance.

Stuck with a frozen dehumidifier that can't get it to restart? Here are a few things you could do before sending it to the service center.

  • Check the room temperature. Do not operate the dehumidifier below the recommended temperatures (65 °F degrees).
  • Make sure there is no blockage on the air ventilation. Keep 1-2 feet distance between walls.
  • Wash the filter every month to prevent dust and other contaminants from making its way to the coils.
  • Use a wet rag and soft brush to clean the coil fin yearly to prevent deposits clogging. If the coils are hidden deep within, the permanent filter is your only hope.
  • If you suspect there are damaged parts or electrical faults, let a certified technician deal with it.
  • Dropped in dehumidification performance or completely broke down after a few months, send it back to the service center. It will be covered under warranty.
  • If the defrost sensor is acting up, gently clean the sensor from dust with a cotton swab.



Kingston Kay

Growing up in New Orleans; one of the highest relative humidity in the United States, Kingston Kay knows a thing or two about humidity. Besides reviewing dehumidifiers for living, you will find him gyming in the basement.