How to Fix a Window Air Conditioner That Freezes Up

Carl Pruit

Several factors can cause a window air conditioner to freeze up and stop working. These range from low refrigerant to extreme outdoor temperatures, not enough ventilation around the unit or even defective parts.

Window Air Conditioner

If your window air conditioner freezes and quits working, a few simple steps might restore it to normal operation.

  1. Unplug the window air conditioner and let the frozen coils thaw out for a day. To prevent any risk of electrical shock, shut off the breaker in the electrical panel that goes to outlet for the air conditioner.

  2. Assist the thawing process by using a hair dryer on a low setting to get rid of any ice that has accumulated on the air conditioner. Use a towel to dry the air conditioner thoroughly and verify that no standing water remains anywhere on the unit.

  3. After 24 hours, turn the breaker switch back on and plug the electrical cord to the air conditioner back into the outlet. Turn the unit's fan on and watch to see that the fan blades turn properly.

  4. Have a certified HVAC technician check that no coolant is leaking, add freon to the unit if needed and verify that the window air conditioner is working properly (see the"Warnings" section below).

  5. Remove any obstacles that could hinder the free flow of air around the outside of the unit. Turn the air conditioner on low cool to make sure it is working.

  6. Tip

    To keep your air conditioner functioning properly, have it serviced in the spring before temperatures start to rise.


    It is illegal for anyone other than a certified HVAC technician to add freon to an air conditioning system. If coolant is leaking from the air conditioner, the HVAC technician is prohibited by law from recharging the freon. The compressor must be fixed or the unit replaced.

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