What Could Be Wrong With My Air Conditioner Not Cooling?

Dirty Filter

• A blocked or dirty air filter prevents air from circulating properly through the air conditioner unit and, in extreme cases, might even cause the AC to shut off. Behind the grille, a filter is fitted to the unit and can be removed for cleaning. You can clean the filter by running warm water on both sides of the filter. If necessary, soapy water can be used to clean the filter. The filter should be inserted back into the unit completely dry. You can either dry the filter by blotting it with a towel or laying it out to dry. If the filter isn't washable or reusable, you should replace it.

Blockage

• Blockage, such as drapes or furniture, might prevent the louvers or vents from blowing air if you hear the unit running but there's no output. All furniture, including chairs or sofas, should be removed from the front area of the air conditioner to allow air to flow freely into the front grille out of the vents. If the unit is installed in a window, confirm that there are no drapes in front of either the grille or the louver. Blockage of the front grille could lead to automatic shutoff of the unit or even damage.

Exhaust Hose

• If the air conditioner is a portable unit that requires an exhaust hose, the hose shouldn't be blocked, kinked or damaged. The exhaust hose should be as straight as possible for the evaporated air to escape. If it needs to be bent, the bend should be slight. The unit's internal cooling element shuts down if evaporated moisture is blocked from exiting the unit. You can look the hose over from top to bottom for damage. If the hose features a tear or any holes, it needs to be replaced. Both connections to the window and the unit must be secure and tightly sealed.

Thermostat

• An air conditioner that blows warm air when "Cool" mode is selected might have a thermostat that's set too high, which prevents the internal compressor from turning on. The compressor engages the cooling coils that cool the air that circulates through the unit. If the compressor activates when the thermostat is dropped, the thermostat was set too warmly to begin with. You'll need to verify that the thermostat is set below room temperature if you want cold air to blow from the AC.