Differentiating Heat Pumps from Split systems?

Hi all,

I’m a newbie inspector and non too happy with the training I got, so I’m trying to fill in with all the nice Nachi online courses. Here is one I’m still not sure on.

How do tell whether a system is a heat pump or a regular split system with condenser outside and furnace/air handler inside. Some heat pumps are clearly labeled as such and some aren’t. One way to know is if the thermostat has an emergency heating mode then it’s clearly a heat pump.

Other than that I’ve gotten mixed information. Thanks in advance for your



You cannot depend on the thermostat because sometimes the wrong one was installed! Look in the compressor/condenser unit (normally outside) for the reversing valve. It is the part that changes the heat pump from summer to winter operations.

I agree and even some of the newer LCD t’stats don’t have a mechanical switch on them for EM Heat. That function is programmable on the display. Look for the reversing valve, it’s usually visible and obvious.


I have a 2004 Lennox heat pump system. A/C summer, heat in winter. Forced air gas furnace back-up. No valve like this on my system. Tag on upper furnace duct says heat pump system.

Key in your locations. Systems to your areas may be different.

Send some pictures.

You have to have a way to reverse refrigerant flow.

Thomas, you will also find a circuit board inside the electrical control compartment of the condensor if it is a HP.

I understand the question, but around here heat pumps are a “regular system”. Other than looking for the reversing valve as mentioned above, in most cases you can also look up the model number on the manufacturer’s web site.

Why look it up when you can look into the fan housingh and see it?