My Window A/C Is Not Cooling the Living Room

Dirty Filter

• A window air conditioner contains a filter that sits behind the front grill. The filter catches airborne particles and dirt and prevents them from blowing into your living room. But an excessively dirty filter can also stop cool air from blowing through the grill. Cleaning or replacing the filter can immediately solve this problem. Refer to your air conditioner's instruction manual for directions specific to your unit.

Dirty Coils

• The coils on a window air conditioner may also collect dirt and debris. This will prevent cool air from circulating properly. There are two sets of coils to examine -- the evaporator coils, which are placed in the front of the unit, and the condenser coils, which face the outside. Unplug your unit and remove the front panel and filter. The evaporator coils are near the air filter. Remove the filter and vacuum the coils with a brush attachment. Use a plastic scrub brush to remove any stuck-on dirt. Rinse off condenser coils with a garden hose from the outside. Or remove the window unit and vacuum the condenser coils with the brush attachment.

Improper Settings

• Window air conditioners can emit cool air and bring in air from the outside. If your unit suddenly stops blowing cool air, check the settings. The switch should be turned to "cool" rather than to "fan." Sometimes the fan button may get pressed accidentally during cleaning or by a child.

Wrong Location

• Modern living rooms tend to contain many electronic items, such as high-definition televisions, gaming systems, stereos and DVD players. All of these items produce heat, even when not in use. If an air conditioner is in close proximity to one or more heat-producing items, its performance can be affected. Or when the unit is placed in a sunny window, it will also have difficulty producing enough cool air.

Improper Unit Size

• A window air conditioner's cooling capacity is measured in British thermal units or BTUs. You need an air conditioner with sufficient BTUs to handle the square footage of your living room. Other factors should also be taken into consideration, such as the number and size of windows in the room and your geographic location. There is a possibility that your air conditioner is not powerful enough for your needs. See Resources for a calculator you can use to determine the number of BTUs an air conditioner must have to cool your living room.

Warm Air Sources

• Your living room should be closed off from any sources of warm air. Check the seal between the air conditioner and window frame for cracks or holes. Close all windows and doors that could be letting in warm air. Shut the doors of rooms without air-conditioning to block warm air from circulating into the living room.