The air conditioner moves heat from one area to another much like the cooling system in a frostless refrigerator. Inside the unit there is a coil called the evaporator, and it is the component that gets cold. A fan pulls heated air from the room across the evaporator coil, and then pushes the cooled air into the living area. Warm air is constantly being pulled back through the air conditioner unit and across the coil, creating a complete recirculating process. In addition, the air conditioner helps to lower the humidity level in your home, and thereby enhance the comfort of the living area. The moisture in the heat-laden air tends to collect upon the chilled coils of the evaporator, much as condensation does on the outside of a glass of iced tea during summertime.

What happens to the heat? It is carried by the refrigeration system to an exterior coil called the condenser. The condenser, which is hot to the touch, is exposed to the outside air. The circulating outside air absorbs the heat, dispelling it outside your home. Meanwhile, air is continually pulled through louvers in the sides of the cabinet and pushed out through the coils. This process eventually eliminates enough of the hot air in your home to make it comfortable.

The same heat-removal principles apply as much to an automobile's air conditioning system as they do to a centralized home or window unit. In a car, the evaporator (which is located behind the dash) removes the heat and transfers it to the condenser (usually located in front of the car's ii radiator). In a home central air conditioning system, the condenser and compressor may be remote (located on the roof or as a separate unit somewhere outside the house). The evaporator of a central air conditioning system is placed within the supply duct plenum of the furnace.

The compressor acts as a pump to circulate the refrigerant through the system. Therefore, you can control the temperature in your home with a thermostat which simply turns the compressor on and off to maintain the degree of coolness you desire. In most cases, the system's blowers continue to run even when the compressor is off. Fan motors consume only a small amount of electricity, and they help keep air circulating within the room even when the cooling system itself is not required. Without continual air
circulation, the cold air would collect near the floor, a condition known as "stratification" which can be quite uncomfortable.

All air conditioners require regular maintenance, consisting primarily of the cleaning and replacing of filters at specified intervals (once every 30 days is not too often). Dirty filters, as you would expect, reduce the air flow and lower the efficiency of the unit. In severe cases, filters that fail to do their job can even damage the evaporator and the compressor. Therefore, you must clean or change the filters regularly.
Filters made of foam or aluminum are washable, you can flush these filters with a hose from the back side. Some air conditioner manufacturers recommend that you then coat the clean filter fibers with a special adhesive to trap particles as the air passes through the filter. Fiberglass filters, however, cannot be cleaned; you must replace fiberglass filters when they become dirty.

If a filter has been clogged for a long period of time, lint and dirt can work their way through to clog the evaporator coil itself. You can remedy this situation by applying a special cleaning solution or a strong liquid detergent to the coil. Spread the solution on the coil and allow it to soak for a few minutes. Then spray the coil with water, and brush away the residue from the front. Continue to flush the coil until it appears to be free from lint and dirt once again.

The water you use to rinse the evaporator coil will flow out the same drain line that carries off condensate water when the air conditioner is operating. Such water usually flows across the base pan to a sump located at the bottom of the condenser fan blade. This fan blade has a special ring around it (called a "slinger" ring) that rises through the puddle at the bottom of the condenser. The slinger ring helps eliminate dripping — except in the most humid weather — and it also increases the efficiency of the condenser