What’s this? Condensing unit

I’m on record as believing that we put undue importance on knowing what things are called.  I’ve witnessed plenty of examples of people knowing what an item was called but not knowing what it did or how it worked.

But we do need to describe things to other people, and if you know the proper names of things around your home when you describe them to people in the trades then you’re more likely to get a positive response.  So here’s the first of some upcoming blog posts that describe the most proper name for things around your home.

Since it’s the middle of summer let’s start with your air conditioning system.  If you have air conditioning then you probably have a split system central air conditioner, which consists of an outside component and some inside components.  And the part of this system that’s outside is most properly called the “condensing unit”.

Condensing unit

The condensing unit is really the heart of the air conditioning system.  It contains the compressor, which is a pump that compresses the refrigerant in order to raise its temperature.  You should be able to see the compressor in the middle bottom of the condensing unit.  It’s the device with the red arrow in the picture below.  This condensing unit also contains the condenser, whose job is to expel this heat to the outside.  Generally speaking the condenser is the outer part of the condensing unit where the refrigerant line runs in a big loop.  There’s a large fan blowing air over these refrigerant lines to expel the heat to the outside and cool the refrigerant.

Compressor inside the condensing unit.

There are two copper tubes that carry the refrigerant between this condensing unit and the evaporator coil inside the house.  The smaller tube is the liquid line and it’s carrying liquid refrigerant from the condensing unit into the house and to the evaporator coil.  The larger tube is the suction line (sometimes called the return line or the vapor line) and it’s taking vapor refrigerant from the evaporator coil out to the condensing unit.  This suction line will be cold during operation and it should be insulated for best efficiency.

There’s also an electrical line supplying 240 volts to the condensing unit.  The compressor uses a lot of power, so 240 volts are necessary.  The fan uses just a little bit of electrical power.

Many people just call this outside component the “air conditioner”.  But it’s really just one component of the entire air conditioning system.  It’s most properly called the “condensing unit”.