How to Repair a Window Unit Air Conditioner

A malfunctioning window air conditioner generally tends to be cheaper to fix than a central air system. Often you'll see a sudden reduction of the volume of cool air or air that is no longer as cool as it once was.

Get some help moving the unplugged window air conditioner to a sturdy table for repair.

Fixing your window air conditioner in this case may be as simple as cleaning it, rather than an all-out repair.

  1. Unplug the air conditioner. Unscrew and remove the front grill. Depending on the model and age, you may need to pry off the grill with the flat end of a screwdriver.

  2. Slide the air conditioner unit out of its place inside the window. Have someone help you move the unit to a sturdy and durable surface.

  3. Look for the air conditioner’s mesh filter covering the fins on the evaporator coil. Remove the filter. Wash the filter with warm water, detergent and a drop or two of bleach. Shake the filter to remove excess water and allow to dry.

  4. Use a hand-held vacuum or attach a brush attachment to your full-sized vacuum cleaner. Run the vacuum over the evaporator coils. Use a heavy-duty brush to remove any dirt that remains on the coils after vacuuming.

  5. Take a closer look at the fins of the evaporator coil. Look for any fins that are bent, and use a special tool known as a fin comb to straighten bent fins. Run the fin comb either up or down the fins to straighten them.

  6. Turn the air conditioner around so that you can see the unit’s condenser coils. Vacuum these coils, and use the heavy brush to remove any dirt that the vacuum doesn’t remove. Use the fin comb to straighten bent coils.

  7. Clean the fan blades and use the vacuum to remove any remaining dirt or dust particles. Place the unit back into the window. Reinstall the mesh filter after it has dried completely. Replace the grill. Plug the air conditioner cord back into the wall outlet.

  8. Warning

    Unplug the air conditioner unit before opening it up for any kind of service.


  • Unplug the air conditioner unit before opening it up for any kind of service.