Cleaning Room AC

Room air conditioners cool one room at a time and are typically installed in a window or through an exterior wall. Cleaning the filter and coils on your room air conditioner will help it perform better and use less electricity. Unplug the air conditioner before cleaning the coils. The filter and indoor evaporator coil are found behind the air conditioner unit’s removable louvered cover on the inside of the home. 

Once this cover is removed, wash the foam filter in the kitchen sink with soap and water. Once the filter is removed, the indoor coil is easily identifiable by its aluminum fins. These fins are a little fragile, so be careful not to bend them when cleaning. An old hairbrush works well for brushing surface dirt and lint off the fins. Wear a dust mask to avoid breathing the dust. Brush in the same direction as the slots between the fins so the bristles penetrate between the fins. Before cleaning, you may want to wet the indoor coil with water from a spray bottle to keep the dust from getting airborne. Dirt trapped deeper in the coil can be removed by spraying a strong household cleanser into the coil, followed by water, which will drain out through the air conditioner’s drain to the outside. 

The condenser coil must also be cleaned and is located in the portion of your room air conditioner that hangs outside the home. This coil is almost identical to the indoor evaporator coil described above but is more difficult to clean. To examine the condenser coil, go outside and peer through the louvered openings in the air conditioner housing, using a flashlight. If there is a lot of dirt noticeable inside the coil, it’s time to clean it. To do so, you’ll have to remove the air conditioner from the window and perform this job outdoors or in your garage. You can remove the conditioner’s housing by removing a few screws. The dirtiest side of this outdoor coil faces the indoors. You can tape your hairbrush to a paint stir or dowel to help get the brush to the bottom of the coil. Use spray cleaner and light water spray from your garden hose to finish the job. Let your unit dry in the sun before replacing the housing and re-installing it. 

Remove the air conditioner’s metal housing to gain better access for cleaning the two coils. Clean dirt from the fan blades too. 

For more information on air conditioning see The Homeowners Handbook to Energy Efficiency Your Home Cooling Energy Guide, Chapter 8 of Residential Energy: Cost Savings and Comfort for Existing Buildings or for specific information about servicing air conditioners for energy efficiency, see Saturn Hydronic Systems Field Guide.