Most people assume warm air from their A/C unit means it’s low on refrigerant. That’s not always the cause. Many times, window and through-the-wall A/C units can’t blow cold air because the evaporator and condenser coils or cooling fins are clogged. Professional cleaning costs over $100. But you can do the entire job yourself in about an hour with a few dollars in supplies. If cleaning doesn’t do the trick, you can always call in a pro (or buy a newer, more efficient unit). Here’s how to clean your A/C unit.
First remove the plastic filter holder/trim panel. It usually snaps off. Then remove it from the window or slide it out of the wall (get help—it’s heavy).
If you’re working on a window unit, remove the mounting frame and the case. The case screws are usually located along the bottom edge. Note the location of any odd-length screws since they have to go back in the same spots upon reassembly.
Then straighten the bent cooling fins with a fin comb (Photo 1). The Frigidaire fin comb kit shown here is cheap and fits most brands of air conditioners.
Buy two cans of A/C coil cleaner (one brand is AC-Safe No. AC-920 from homedepot.com). Vacuum all visible buildup from both coils (Photo 2). Then spray both coils with the cleaner (Photo 3). While the foam works, clean the fan blades with household cleaner and a rag. If the fan motor has plastic- or rubber-capped oiling ports, pop them and squeeze in a few drops of electric motor oil (pros use the Zoomspout oiler from zoomspoutoiler.com).
Wash (or replace) the air filter and reinstall the unit. It just might blow a lot cooler. If not, you have other problems!