Place the window AC in a shaded location to help it run more efficiently. Inspect the seal between the window and the AC after installation. Adjust the AC to fill any openings, or patch the openings with plastic, fabric or tape.
Clean or replace the air conditioner filter monthly, or more frequently if you have pets or run the device constantly. Remove the front casing of the AC to access the filter, although some models feature pull-out filters similar to a dryer filter. Scrub off any dirt or grime from a reusable filter, and wash the filter in warm, soapy water if the material allows it. Wait until the filter is completely dry before reinstalling it. Replace the filter as needed.
Vacuum the front grill and the coil fins -- the metal grating on the rear of the air conditioner -- while you are replacing the filter. Use an upholstery brush attachment on the vacuum, and avoid bending the fins. If possible, remove the grating and wipe down the condenser coil and any hard-to-reach dirt.
Run a stiff wire along the condensation drains during your monthly AC maintenance. Remove any dust or debris that may be clogging the drain and preventing the unit from reducing humidity.
Allow the window AC to rest for at least five minutes after you turn it off. Restarting the AC immediately after shutting it down can damage the compressor.
Pull the AC out of the window during cooler months. Alternatively, you can purchase an air conditioner cover and secure it to the air conditioner if you want to leave the device in the window. Avoid exposing the air conditioner to harsh winter conditions.