How to Clean an Attic AC Evaporator Coil

While your air-conditioning unit is circulating cool air into the house, it also is circulating dust, hair and other airborne dirt that can build up on its coils. The evaporator coils on an AC unit are inside, usually near where the duct attaches to the unit.

Things You'll Need

• Screwdriver
• Vacuum or compressed air
• Bristle brush
• Cleaning solution
• Fin comb

Instructions

1. Detach the duct from the AC unit. You can remove the screws that attach it, then gently pull it back so that you can access the coils.

2. Gently go over the coils with the hose vacuum attachment. You also can use a can of compressed air to complete this step but it may push debris further into the system.

3. Go back and forth over the coils with a firm bristle brush to knock loose any remaining debris.

4. Apply a household cleaning solution to the coils. It is best to use a spray bottle and spray the coils. The cleaning solution should sit on the coils for a few minutes.

5. Go back over the coils with a bristle brush to help remove any buildup.

6. Use a fin comb to straighten bent coils. Place the comb gently between the coils and apply a little bit of pressure to bend them back into place.

Tips & Warnings

• Avoid applying too much force directly to the coils because they are fragile and may bend or break.

References

• Air Conditioning Cooling Coil or Evaporator Coil Cleaning Methods
• Clean indoor evaporator coils
• Outdoor Coils Cleaning: Air Conditioners and Heat Pumps