How to Clean an Air Conditioner Window Unit

A simple cleaning is all it takes to keep your room air conditioner humming.

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Air conditioners work more efficiently when the evaporator and condenser coils or cooling fins are clean and the fins are straight. Save money and keep your house cooler by cleaning a room air conditioner yourself.

Tools Required

  • 4-in-1 screwdriver
  • Fin comb
  • Leather gloves
  • Rags
  • Shop vacuum

Materials Required

  • A/C coil cleaner
  • Electric motor oil
  • Household cleaner

How to Clean Your A/C Unit

Most people assume warm air from their air conditioning unit means it’s low on refrigerant. That’s not always the cause. Many times, window air conditioners and through-the-wall air conditioners can’t blow cold air because the evaporator and condenser coils or cooling fins are clogged. Not keeping a unit clean is one of the most common air conditioner mistakes users make.

Professional cleaning can be expensive But you can do the entire job yourself in about an hour with a few dollars in supplies. If cleaning doesn’t do the trick, you can always call in a pro (or buy a newer, more efficient unit). But before you do that, check out our step-by-step air conditioner cleaning instructions below.

Project step-by-step (6)

Step 1

Cleaning an AC Unit

First, remove the plastic filter holder/trim panel. It usually snaps off. Then remove the unit from the window or slide it out of the wall. Get help. It’s heavy.

If you’re working on a window AC unit, remove the mounting frame and the case. The case screws are usually located along the bottom edge. Note the location of any odd-length screws since they have to go back in the same spots upon reassembly.

An outdoor air conditioning unitcosmonaut/Getty Images

Step 2

Comb Out the Mats

  • Straighten the bent cooling fins with a fin comb.
  • Match the correct end of the air conditioner fin comb to the fin spacing on your coils.
  • Then insert the air conditioner fin comb and pull up to straighten the fins.
  • Wear leather gloves to prevent nasty cuts.

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Step 3

Air Conditioner Fin Comb Details

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Step 4

Clean Out the Crud

  • Buy two cans of AC unit coil cleaner.
  • Before applying the cleaner, vacuum all visible buildup from both coils.

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Step 5

Apply Foam Cleaner

  • Shoot the spray over the entire surface of both coils and let the foam do the work for you.
  • If the buildup is heavy, brush in the direction of the fins with a nylon-bristle brush.

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Step 6

Service the Fan Motor

  • While the foam works, clean the fan blades with a household cleaner and a rag.
  • If the fan motor has plastic- or rubber-capped oiling ports, pop them and squeeze in a few drops of electric motor oil (pros use the Zoomspout oiler) and recap.
  • Finally, wash (or replace) the air filter and reinstall the unit.
  • It just might blow a lot cooler. If not, you have other problems!

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