A dusty window air-conditioner filter restricts airflow and makes the unit work harder. Cleaning it is straightforward when the unit is switched off, the filter is dried completely, and the delicate coil fins are left undamaged.
Power down
Switch the unit off and unplug it before opening the front panel. Remove the filter according to the manual and vacuum loose dust outdoors or over a bin.
Wash and dry
Rinse a washable filter with lukewarm water from the clean side toward the dirty side. Use mild detergent only if the manual permits it. Shake off water and let the filter dry completely in shade before reinstalling.
Inspect the cabinet
Wipe the grille and accessible surfaces with a slightly damp cloth. Do not spray water into controls or bend the aluminum fins. If ice, mold, or a blocked drain appears, arrange service instead of forcing the unit to run.
Check the filter monthly during heavy use and more often in dusty rooms.