Why Is My Window AC Not Blowing Out Cold Air?

Filter

• The first thing to check when the unit fails to blow cold air is the air filter because a dirty air filter hinders production of cool air by barely allowing circulatory air into the unit in the first place. Particularly dirty air filters can cause the unit to shut off automatically and sometimes even cause damage. Pull open the grille of the window unit with your fingers. The filter has a designated spot either against the unit or against the grille. Slide the filter out of its position, and wash both sides of it with warm water until it's clean. Allow the filter to dry, or dry it with a clean towel and reinsert it back into the unit.

Room Temperature

• If the unit seems to be blowing cold air but doesn't feel cold enough, the room temperature might be too low for the air conditioner to have an effect. If the thermostat of the window unit is set to, say, 65 degrees Fahrenheit but doesn't blow cold air, the temperature of the room might be 60, causing the unit's internal compressor to stop working as the demand of 65 degrees Fahrenheit has already been met. Turn the unit off unless you simply wish to circulate the air within the room. When the room temperature rises, try the AC again.

Outdoor Temperature

• When the outside temperature is very hot, the running AC might cause ice buildup on the internal coils of the unit, preventing the production of cold air within the unit. The unit continues to run, so the air feels warm. You can defrost the coils by setting the thermostat to it's highest setting and turning the fan setting to "High." Another way to defrost the coils is to turn the air conditioner off completely.

Open Doors

• If the air emitted by the AC unit seems to not cool the room, inspect the room for possible air escape outlets, such as holes in the wall, open windows or doors or open vents in the floor or ceiling. If the room is not airtight, the cool air produced with the air conditioner will leak out of room as soon as it's produced. Seal off all possible avenues of leakage before you turn the AC on.