The three main parts of an air conditioner unit are the compressor, the condenser and the evaporator. The compressor and condenser are located on the outside of the air conditioner and the evaporator is located on the inside.

The basic functioning of the air conditioner is based on the principle of successive heating and cooling of a highly volatile liquid, such as a Freon. The liquid first enters the compressor, where it is compressed into a gas. This releases heat and makes the liquid cooler. The dissipated heat is radiated outwards with the help of a fan. The liquid then enters the condenser, where it absorbs heat from the surroundings to reconvert into a gas. Hence, the surroundings become cool. The entire process continues cyclically and this causes cooling of the room.

Besides the three fundamental Air Conditioner Parts, an air conditioner also has a hot coil on the outside to dissipate heat, a cool coil on the inside to absorb heat, two fans (one outside and one inside) and a control circuit to modify the temperature. This is done by changing the rotation speeds of the fans using a potentiometer.

The most important and expensive Air Conditioner Part is the compressor. Companies provide warranties on the compressor and a good quality compressor can function efficiently for several years. New compressors can be bought and installed into the air conditioner if the original one develops faults. It is ideal to have a compressor made by the same company as the rest of the air conditioner. However, it is also necessary to mention that only a few companies manufacture their own compressors; the rest just buy them and install in their units.

Condensers and evaporators can also be replaced. The same case is applicable for the cooling and heating coils. Problems in the coils lead to faulty dissipation of heat, thus causing unsatisfactory results. Fans are the easiest components of the air conditioner units to replace. They are simply fitted by screws on the outer part of the air conditioner and with wires to the air conditioner circuit board.

One more component of the air conditioner is its outer cover. The cover has no other function except to lend an aesthetic appeal to the air conditioner. It is generally made of molded plastic and is available in a wide range of colors and designs. The same can be said about buttons and knobs. A water-carrying duct is essential if the air conditioner faces the road on the outside.