An air conditioner consists of 3 main parts, the evaporator coil, the compressor, and the condenser. In a central air conditioning system, which cools the entire home, the evaporator coil is installed in the supply plenum of the furnace, and the compressor/condenser unit is the part of the system located outside the home. The evaporator and compressor/condenser unit are connected via refrigerant lines that send the refrigerant from the compressor in a hot and high pressure gas into the condenser where it cools and turns to a liquid and then travels to the evaporator. While in the evaporator it continues to cool and draws the heat from the air circulating through the home. The refrigerant then transforms back into a liquid and is drawn into the compressor where it is changed back into a hot high pressure gas. The refrigerant not only cools the air in the home, it also reduces the humidity. So any moisture in the air is collected and then drained away in the evaporator coil.