Dehumidifier Frost or Ice Buildup
If your dehumidifier has frost or ice buildup on the coils, the problem could be caused by low room temperatures, restricted airflow, a dirty air filter, or a sealed system issue. Before replacing any parts, inspect the most common causes listed below.
Safety Notice: Always unplug the dehumidifier before servicing it. Allow any ice on the coils to melt completely before inspecting or testing internal components.
Possible Causes
- Low room temperature
- Dirty or clogged air filter
- Blocked air intake or discharge
- Failed fan motor
- Dirty evaporator coils
- Faulty defrost thermostat or sensor
- Refrigerant leak
- Failed compressor
1. Low Room Temperature
Most Common Solution
Most dehumidifiers operate best in rooms above approximately 65°F (18°C). When the room temperature is too low, moisture can freeze on the evaporator coils instead of draining into the water bucket.
What to do:
- Verify the room temperature is within the manufacturer's recommended operating range.
- Move the dehumidifier to a warmer location if necessary.
- Allow the ice to melt completely before restarting the unit.
2. Dirty or Clogged Air Filter
A clogged air filter restricts airflow across the evaporator coils, allowing the coils to become cold enough for ice to form.
What to do:
- Unplug the dehumidifier.
- Remove and inspect the air filter.
- Clean or replace the filter if it is dirty.
- Restart the unit after the coils have thawed.
3. Blocked Air Intake or Discharge
Restricted airflow reduces the amount of warm air passing over the evaporator coils, increasing the likelihood of frost buildup.
What to do:
- Remove any objects blocking the air intake or discharge.
- Clean dust and debris from the air vents.
- Ensure the unit has adequate clearance on all sides.
4. Fan Motor
The fan motor circulates air across the evaporator coils. If it slows down or stops working, frost can quickly develop.
What to do:
- Turn the unit on and verify the fan is operating.
- Listen for unusual noises or slow fan operation.
- Replace the fan motor if it is defective.
5. Evaporator Coils
Dirty evaporator coils reduce airflow and heat transfer, increasing the likelihood of frost or ice buildup.
What to do:
- Disconnect power.
- Inspect the evaporator coils for dirt or debris.
- Carefully clean the coils using a soft brush or vacuum.
6. Defrost Thermostat or Sensor
Many dehumidifiers use a defrost thermostat or sensor to prevent excessive ice buildup. If this component fails, the unit may not enter its automatic defrost cycle.
What to do:
- Inspect the defrost sensor or thermostat.
- Test it according to the manufacturer's specifications.
- Replace it if it is defective.
7. Refrigerant Leak
Low refrigerant pressure can cause the evaporator coils to become excessively cold, resulting in frost or ice formation.
What to do:
- Look for signs of an oily residue around refrigerant lines.
- If frost continues after improving airflow, have the sealed system inspected.
- Repair any refrigerant leaks before recharging the system.
8. Compressor
A failing compressor may cause improper refrigerant circulation, resulting in abnormal coil temperatures and excessive frost buildup.
What to do:
- Listen for unusual compressor noises.
- Verify the compressor is running properly.
- Replace the compressor if it has failed.
Need Help Finding the Correct Part?
If you need help identifying the correct replacement part, send us your complete dehumidifier model number and a clear photo of the appliance identification label before placing your order. Our team will verify compatibility and help ensure you receive the correct replacement part the first time.