Anatomy Of A Central Air Conditioning System

If you’ve gotten a quote for installing a new central air conditioning unit recently, you might have been a bit confused by the lingo that was used to name the different parts of the system. What does a condenser and coil have to do with anything? You just wanted a quote on a new ac unit right?

Let me shed a little light on the terms that describe each of the components that make up your air conditioning system.

CONDENSER

That round’ish piece of equipment that sits outside on the ground that everyone refers to as their air conditioner is technically referred to as a condenser. You’ll also hear it called the ‘outside unit’ as well. Part of your condenser is called a coil, or condenser coil, not to be confused with the evaporator coil that is inside your home attached to the furnace.

EVAPORATOR COIL

This is the piece of your air conditioning system that most people never see. It’s contained in a metal box called a plenum, and sits on top of your furnace. If you have a horizontal furnace in an attic, the evaporator coil will sit on one end of the furnace instead of on top. The ‘inside unit’ or ‘indoor coil’ are other common names that are used when talking about your evaporator coil.

LINESET

Lineset refers to the copper refrigerant lines that run from your condenser (the outside unit) to your evaporator coil.

COMPRESSOR

It’s very common for people to make the mistake of calling their outside unit the compressor instead of the condenser. A compressor is actually a big component that sits inside the condenser (the outside unit).

PLENUM

The plenum is the metal box that sits on top of your furnace and houses the evaporator coil.

CONDENSATE DRAIN

The condensate drain is the white plastic (PVC) pipe that runs from your evaporator coil to the drain in your floor, or to the condensate pump that was installed if you don’t have a floor drain. This pipe allows the condensate (moisture) that the evaporator coil produces to be drained out of the plenum.