Basic Air Conditioning

The operation of a home air conditioner is fairly simple. A compressor within the air-conditioning unit cycles Freon (a trademarked name for chlorofluorocarbon gas), raising its temperature. The gas runs through a series of coils, cooling and condensing along the way. In a liquid state, the Freon is piped through an expansion valve, in which it evaporates, expands, and cools. The cold gas is pumped through a set of coils that absorb the heat from the surrounding air, cooling it.

Basic Filtration

A fan then distributes this cool air from an air handler unit and via a series of sealed ducts through the home. (Window units combine the heating and cooling coils in a single housing, and don't use air handlers.) Before the air actually circulates through the system, it passes through an air filter, which traps dust, dirt, pollen, smoke, pet dander and various allergens.

Air Filter Construction

Air filters are made from fiberglass or polyester fibers, which allow air to pass but trap large particles. The fibers are contained in a paper or plastic frame that fits over the air intake within the home, or within the air handler unit. Air filters can also trap toxic chemicals from cleaning agents, polishes, detergents and other common household substances.

Change Your Filter

Air filters play an important role in indoor air quality. If they are not changed regularly, they can no longer effectively remove dust, allergens and toxins, posing a greater risk to the health of the inhabitants. Most air filters should be changed once every three months, more frequently in periods of summer heat and heavy air-conditioning use.

Air Purification

While effective in removing allergens and toxins from indoor air, basic air filters do nothing to protect the home against bacteria, mold and viruses, which are small enough to pass through them. To completely clean a home's air, an air purifier is needed.

Source:

How It Works: How Air Filters Work

Air Conditioner Selection: Your Information on How Air Conditioners Work