The dirty side of air conditioning coils are those that face into the airstream while the clean side faces away from the airstream. Brush away any loose dirt and debris from the coil with a stiff brush. You can make the brush work more effectively by wetting the dirt on the coils with an outdoor coil cleaner that works to soften up the dirt.
It can be difficult to access the indoor coils on the evaporator unit, but if you can access them, it makes sense to clean them at least once a year. Neglecting to clean these coils yourself or have them cleaned by a professional can result in a significant reduction of the life span of your air conditioner. Before that happens, dirty indoor coils will lead to increasingly higher cooling costs.
Pressurized air or water is the most effective way to clean the blower on a central air conditioning unit. The more dirt that builds up on the blower, the less effective it is as moving air over the cooling coils and then into the house. If you don’t have access to a pressured cleaning system, you can still do an adequate job of cleaning by using a vacuum cleaner as long as the debris isn’t greasy.
Remove a portable air conditioner completely from its place inside the window frame for proper cleaning. Remove the metal cover so that you gain access to the indoor and outdoor coils. You can use an old hairbrush for cleaning window unit coils. Inspect the fins on the air conditioner and straight out any fins that have gotten bent.
Spray a standard household cleaner directly into the coil of the room air conditioning unit. Allow the cleaner to work into the coils for a few minutes and then rinse with water. Allow excess water to run into the pan that forms the bottom of the window unit so that it can drain outdoors.
Try loosening the condenser coil of the window unit so that you can turn it outward enough to work on the inside surface of the aluminum fins. Clean with a brush, water and household cleaner. If the coils are very dirty, use a special outdoor coil cleaner. Allow the window unit to dry completely before reinstalling it into the window frame.