An evaporator coil is used to absorb heat and transform it into cooled air before it is distributed around a home. Inside an evaporator coil is a refrigerant that is constantly rotated to an external compressor until the next wave of hot air is sent from a central furnace.
In a central air conditioning system, an evaporator coil is generally found on the cold side of the system. The cold side is typically installed inside an attic, internal closet space or a crawlspace, and consists of an expansion valve alongside a cold temperature coil. The system operates in conjunction with the hot portion of the central air conditioning system that pushes air through the pipes and ductwork.