How to Clean a Central Air Conditioning Unit

A central air conditioning unit is a major investment for a homeowner.

Not only can the unit be expensive to install or replace, an inefficient running unit will cost you money on your home energy bills. A simple annual cleaning will make all the difference when it comes to keeping your air conditioner in top running condition and protecting your investment. You don't need any special skills or tools, just a couple of hours of your time. .

Shut off the electrical power to the unit before you begin.

Start outside by cleaning the condenser. Unscrew and remove the metal box on the outside of the unit. Be careful not to bump the metal blades as they are easily bent.

Vacuum the metal blades, known as fins, using a soft brush attachment. You'll see debris such as leaves, dirt, grass and cottonwood, all of which block the airflow and reduce the air conditioner's ability to cool.

Unscrew the fan to vacuum further inside the condenser. You can't remove it since it is wired in, but you can lift it a bit in order to clean more thoroughly.

Replace the fan and the outer box and move indoors to clean the evaporator inside the house.

Locate the evaporator which is usually found inside a metal duct close to the blower. Vacuum its fins the same way you cleaned the fins on the condenser.

Clean the blower using the same vacuum attachment and then replace the filter. Turn the power back on and test the unit.

Things You Will Need

  • Screwdriver
  • Vacuum
  • Soft brush attachment
  • Filter


  • Clean the condenser when the temperature is at least 60 degrees. If it's any cooler than that, it will be more difficult to test it.
  • Some motors have lubrication points. Check your owners manual, and if yours does put a few drops of electric motor oil in each one.