What is an evaporator coil?
An evaporator coil is the indoor coil in an air conditioning system where liquid refrigerant evaporates and absorbs heat from the room air passing over it. It is the cooling half of the refrigerant cycle that sits inside the indoor unit or air handler.
The evaporator coil is a finned metal coil inside the indoor unit of an air conditioner. Cold, low-pressure liquid refrigerant flows through its tubes and boils into vapour as it absorbs heat from the warm room air that a blower pulls across the fins. The air that comes out the other side is cooler and drier, and the heat it gave up is carried away by the refrigerant to the outdoor condenser.
In a typical split system, the evaporator coil sits behind the indoor unit's front panel, and in a ducted or cassette setup it is housed in the air handler above the ceiling or in a corner of the unit. Because it is the part that actually pulls heat out of the room, its condition has a direct effect on how well the system cools.
Dust, mould, and grime build up on the fins over time. A dirty coil restricts airflow, makes the system work harder, and can freeze over if the air cannot pass through it properly. Condensation collects on the coil and drains through a pipe, so a blocked drain tray can cause leaks or a damp smell. Cleaning the coil is a standard part of aircon servicing, and technicians also check refrigerant pressure at the coil to confirm the system is charged correctly.
If you are looking for a provider who handles this work, the aircon servicing listings in this directory cover contractors who clean and inspect indoor units in Yishun.
Evaporator coil is sometimes shortened to "evap coil" in trade talk. It is distinct from the condenser coil, which sits in the outdoor unit and releases the heat.