Does an air handling unit go inside or outside?

Right now every HVAC pro that saw this article headline said something like, "Where does an air handling unit go? Who doesn't know the answer to that?!"

One thing we've learned over the years is that it is very easy to forget what the average person doesn't know about HVAC. When I started in this industry, I didn't know what an air handler was. I knew that when I turned the thermostat temp down, the house got cool, and when I turned it up, the house got hot. I wasn't much interested in knowing anything beyond that. So, if you're like I used to be, you too might wonder....

Does the air handling unit go inside or outside?

Generally, when we use the term 'air handling unit' we are referring to a device that forms one half of an HVAC central heating and air split system. A split system always has an outside component and an inside component. The air handler is always the inside component. It holds the fan that moves air around, and the evaporator coil that works in conjunction with the outside condenser to do the actual cooling.

So, when an HVAC technician calls something an air handling unit, they are referring to a unit installed somewhere inside the house.

That Being Said....

It is always the case that an air handler is located inside, but it is not always the case that the stuff inside an air handler have to be inside. For example, a packaged unit combines the compressor, condenser and evaporator coils, and the fan in one big cabinet that is always installed outside. Which means that unlike a typical outside condenser, a package unit does not need to work with a separate inside air handling unit.

Questions or Comments About Air Handlers?

Do you have any 'obvious' HVAC questions that you don't know the answer to? Ask them here, on Facebook or on Twitter. And don't be embarrassed, because the geniuses who 'know' all the answers didn't always know them.