If your window unit air conditioner isn't working as well as it used to, it may just need a deep cleaning. Air conditioners that aren't cooling the room very well may need more refrigerant, but a buildup of dust and other debris on the appliance's filter, coils and other hardware could also be the culprit. Not only is a dirty air conditioner inefficient, but it can also be dangerous to your health, as it could be circulating mold spores into your home. A few times a year, take your window unit apart and inspect it to keep it running like new.
Unplug the air conditioner. Then remove the air unit's plastic trim panel, most likely by snapping it off. Have a family member or friend help you slide the air conditioner out of the window and set it onto a worktable.
Remove the unit's mounting frame and case by using a screwdriver to undo the screws that hold them into place; the screws are typically located along the bottom edge of the case. Set the screws in a safe location so you don't lose them.
Straighten any bent cooling fins using a specialized fin comb. Use a vacuum with a soft brush attachment to remove any dust and debris from both of the unit's coils.
Spray the two coils liberally with a can of foaming air conditioner coil cleaner. Allow the cleaner to sit on the coils as recommended by the manufacturer.
Wipe down the air conditioner's fan blades using a general household spray cleaner and a soft cloth. Open any of the fan motor's plastic- or rubber-capped oiling ports and lubricate them with a drop or two of electric motor oil for lubrication.
Vacuum the unit's filter or replace it with a new one, especially if you see any mold spores on it or smell mildew in the air. Pour a cup of bleach into the access opening of the condensation drain line to kill any mold and mildew that's growing in it. Put on a pair of protective latex or plastic gloves and wipe the water drip pan using a cloth dipped into bleach. Allow all of the parts to thoroughly dry before reassembling the air conditioner unit and placing it back into the window.