AC Systems don’t create cold air, instead they transfer heat from indoors to the outdoors. Refrigerant cycles through the coils to facilitate this transition of heat. Most coils are generally made of aluminum and copper, with copper tubing looped through thin sheets of closely spaced aluminum to provide a larger surface area for air to pass over. AC coils are classified by two different types: evaporator coils and condenser coils.
What are Evaporator Coils?
Evaporator coils are inside the indoor AC unit. The blower wheel or blower fan blows air over the evaporator coil, which in turn absorbs the heat from the air. This heat is transferred from the coil to the refrigerant and gets run to your outside AC unit to disperse the heat. The transfer of heat to the evaporator coil also causes water vapor in the air to condensate, providing a dehumidifying effect. Keeping the evaporator coil clean is important! When an evaporator coil is dirty, it leads to the following:
Your energy bills are abnormally high, a dirty evaporator coil causes the system to work more often as it can no longer transfer heat efficiently.
Ice can form on the evaporator coil, causing the AC compressor to work harder and potentially cause component failures.
What are Condenser Coils?
Condenser coils reside in your outside AC unit, referred to as a condenser unit. Refrigerant from your evaporator coil is pumped outside to the condenser coil. The fan in the condenser unit blows air over the condenser coil cooling the refrigerant inside. The cooled refrigerant then is pumped back inside and then the process repeats. As part of this heat exchange process, the refrigerant changes states from a gas to a liquid and back to a gas. The liquid refrigerant pumped into the evaporator coil is pumped through an expansion valve which causes the refrigerant to cool down. As the liquid refrigerant passes through the evaporator coil, it heats up and turns into a gas. The gas is then pumped to the condenser coil and condenses back into a liquid as it passes through it. The condenser coil is just as important as the evaporator coil and needs to be kept clean for the same reasons as the evaporator coil.