A dehumidifier icing up most often happens because the unit is operating in temperatures that are too cold. Many dehumidifiers aren't equipped to run at temperatures below 65 degrees Fahrenheit, though there are some models made for dehumidifying cooler basements that operate in lower temperatures. Poor airflow due to a dirty filter can also cause the dehumidifier coils to freeze. Don't operate a dehumidifier with frozen or extremely cold coils. Identify and correct the underlying cause, and de-ice the machine to get it working again.
Depending on the brand of dehumidifier, some frost can be present when the unit is first activated. This is generally because refrigerant is rapidly moving through the evaporator coil. If the dehumidifier is operating properly, this frost will disappear within about 60 minutes.
1. Move the Dehumidifier
Poor airflow is the most common reason for a dehumidifier icing up. This can cause the condenser coils to freeze because the water can't drain off them quickly enough. This can happen if the filter is dirty or if the dehumidifier is close to something that obstructs the airflow.
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To fix a dehumidifier icing up, start by positioning the dehumidifier in an area where there is at least 1 foot of clearance around the unit. This allows for proper air circulation during its operation. Close all windows, doors, and other outside openings to make sure your unit isn't attempting to remove excess moisture from areas outside the immediate room.
2. Check the Room Temperature
Determine the temperature of the room by checking a nearby thermostat or by using a hand-held thermometer. Many dehumidifier models can only operate without freezing up when temperatures are above 65 degrees, although some Frigidaire models can operate when temperatures are above 41 degrees, and certain Soleus-brand units can operate in temperatures down to 36 degrees. If it's colder than the temperature at which your unit is designed to operate, turn off the unit until the temperatures rise above that threshold.
3. Inspect the Air Filter
Another common cause of an iced up dehumidifier is a dirty filter. Check the dehumidifier filter for dirt and buildup. To do this, unplug the unit from the outlet, and open the filter compartment. If the filter is dirty, it may restrict airflow through the unit and lead to freezing.
Check the owner's manual for filter cleaning instructions. You can typically vacuum the surface of the filter to remove dirt, and some filters can be washed in warm water if they're extremely dirty. Once the filter is clean and dry, place it back in its compartment. Allow the unit to defrost and then restart it to verify that your dehumidifier works.
4. Raise the Dehumidifier
Elevate the dehumidifier unit to take advantage of warmer temperatures off the floor. Unplug the dehumidifier, empty the water from the tank, and let all ice buildup melt from the unti. Place the unit on a table or another sturdy surface. Reinstall the tank, plug in the unit, and restart the dehumidifier.