How to Pressure Wash & Clean Window Unit Air Conditioners

James Clark

Cleaning the condenser coils on a window air conditioning unit helps the appliance draw air and cool the room more efficiently. Over time, grime and dirt can build up between the thin metal plates, forcing the motor to run harder and potentially wearing out the unit much more quickly. Mold and mildew can also accumulate on the metal fins. The force of a pressure washer makes fast work of this tough cleaning job, but you'll need to take precautions to save time without damaging the air conditioner.

Watch out for painted surfaces when power washing a window AC unit.
  1. Switch off the window AC before cleaning the unit.

  2. Start the pressure washer.

  3. Hold the pressure washer wand with both hands. Place one hand on the trigger handle and the other about midway along the wand. This helps you control the water blasting through the nozzle and avoid making potentially damaging mistakes.

  4. Guide the wand tip up and down along the steel condenser coils on the back of the window air conditioner. Work from one side to the other and back again, if necessary. The coils are clean when the water drips clear from the bottom of the AC unit.

  5. Pressure-wash the top and underside of the air conditioner to remove mold and grime. Avoid the expanding curtains on the left and right sides of the AC unit. The flexible, corrugated curtains cannot withstand the force of a pressure washer and will likely cave in or collapse. Clean these parts with paper towels dampened with ammonia.