How to Clean Coils on a Central Air Conditioner Unit

An evaporator isolated against a white background.
What You'll Need
Garden hose
Spray nozzle

A central air conditioner is a unit that spreads cold air throughout your home or business via a duct system. Within the machine itself, air is pushed through several coils containing refrigerant that cool it before its pushed through the duct work and into the home. These evaporator coils should be cleaned once a year to keep the unit working efficiently and to help avoid creating allergy problems for you and your family.

Step 1 - Turn Off Electricity

Before working on any appliance or device powered by electricity, it is important to shut it off at the source. With a central air conditioner, you will want to first turn it off at the thermostat. Afterward, switch the power to the unit off at the breaker box; there should be a breaker dedicated for this purpose. If you cannot find it for some reason, it would be smart to call your electric company to have them help you.

Step 2 - Locate Your Main Unit

If you do not know where the main part of your unit is installed, you will want to look around for it. Generally, you can find panels that cover it outside your home of office, on the side of the building; however, they can be located on the back of the building, on the ground near your home or office, or even on the roof.

Once you have located the panels covering your air conditioner, remove them by loosening the screws. Make sure that the area around you is clean so that nothing will fall and hurt the air conditioner while you are working. After everything is unscrewed, pull the panel away, taking note of how you removed it so that you will be able to reattach it easily when you're done.

Step 3 - Spray the Coils

Locate the coils and spray them down with water from a garden hose. Use a spray nozzle specifically so you can dislodge any loose debris easily. Follow up by using a degreaser to take care of anything else. Let it sit on the coils for over half an hour before proceeding.

Step 4 - Rinse

Once the degreaser has set on the coils, rinse a portion to make sure that it worked. If it has not fully cleaned the coils, it may need to sit a little longer.

If the coils are clean, you will want to rinse them off completely with your hose nozzle. Make sure it is getting the heaviest water pressure possible so any remaining grease and grime on the coils washes away. To make sure you don’t cause yourself injury, stand at least two to three feet away the entire time. Also make sure that the nozzle is about a foot away from the coils so that the water pressure will not harm the system.

Step 5 - Finish Up

Allow the coils to fully dry before reattaching the panel to the outside of the air conditioner. It is of the utmost important that no moisture remains inside. Turn the electricity to the unit back on and you're finished.

By maintaining your air conditioning coils, you will make sure that your unit will work longer and more efficiently.