HVAC or Heat Pump

[Joe Reilly]

Guys / Gals -
I know there is a difference in the operation between HVAC units and Heat Pumps, but is there any easy visual way to tell the difference ?

I read that the Thermostat should have an 'emergency on' feature, well the house I just did, did not have this feature, and I thought the thermostat was mis-wired when the Compressor turned on when I turned the heat on, (which I know understand is common for Heat Pumps).

I am just looking for an easy visual way to tell the difference from the outside of the unit.

TIA

[Jerry Peck]

... between HVAC units and Heat Pumps,

A heat pump is an HVAC unit.

I think your question is about the difference between 'straight cool'/'cool only' and 'heat pump'.


... is there any easy visual way to tell the difference ?

Most heat pumps will state "Heat Pump" on the label, some will have "HP"in the model number, either at the front of the model number or the back of the model number (of the outside unit).

With straight cool/cool only systems, the outside unit is the condenser unit and the inside unit is the evaporator unit. With heat pump systems, the outside unit is the outside unit and the inside unit is the inside unit as their use swaps depending on if it is during cooling use or heating use.

We have some former HVAC guys here who can add to ... and correct as needed ... the above simplistic information.

[Joe Reilly]

Jerry -

No my question is how can I easily differentiate between the 2 units when looking at them, not what they do, but what they look like. :)

[Jerry Peck]

Jerry -

No my question is how can I easily differentiate between the 2 units when looking at them, not what they do, but what they look like. :)

Joe,

This part was simply correcting terminology:


A heat pump is an HVAC unit.

I think your question is about the difference between 'straight cool'/'cool only' and 'heat pump'.

This part answered your question:


Most heat pumps will state "Heat Pump" on the label, some will have "HP"in the model number, either at the front of the model number or the back of the model number (of the outside unit).

[Dom D'Agostino]

Jerry -

No my question is how can I easily differentiate between the 2 units when looking at them, not what they do, but what they look like.

Are you referring to the exterior condensing unit? If so, look inside the cabinet as many or most will have a visible reversing valve if it's a heat pump. Look it up for some photos or examples.

[Dan Hagman]

The best ways are to check the thermostat for the emerg heat setting in the mode, also look inside the condenser for the reversing valve and the heat pump compressor will have a crank case heater that can be seen on older units, the newer units have an insulation blanket around the compressor so you can only see the wires coming out of the bottom of the blanket.

[Joe Reilly]

The best ways are to check the thermostat for the emerg heat setting in the mode, also look inside the condenser for the reversing valve and the heat pump compressor will have a crank case heater that can be seen on older units, the newer units have an insulation blanket around the compressor so you can only see the wires coming out of the bottom of the blanket.

The Thermostat did not have an emergency heat setting which is what thru me off in the 1st place and when we turned on the Heat, the compressor started, so there was not sure sign it was a heat pump...Thanks for the reassurance

[Jerry Peck]

The Thermostat did not have an emergency heat setting which is what thru me off in the 1st place and when we turned on the Heat, the compressor started, so there was not sure sign it was a heat pump...Thanks for the reassurance

You could have a heat pump with no emergency heat.

Of course, though, that could leave the house without adequate or sufficient heat on those days when it is cold enough to need that emergency heat.

It is possible that the heat pump system was installed with no backup heat strips. It is just as possible (more likely even?) that someone replaced the thermostat with the wrong type thermostat (did not have an emergency heat setting and there may actually be backup heat strips installed). The ac guys will know if installing the wrong type or thermostat, one for straight cool, will work on a heat pump, I'm just guessing as to that possibility.

[Gunnar Alquist]

Jerry -

No my question is how can I easily differentiate between the 2 units when looking at them, not what they do, but what they look like. :)

Joe,

One way that I use to identify the difference is to look at the air handler. Presumably, you know what a gas-fired, forced-air furnace looks like. The air handler (furnace-sized metal box but doesn't have a gas supply, burners, etc.) pretty much just has a blower and a coil inside. In my area, generally A/C or Heat Pump, but I did see an electric resistance heater once. Kind of surprised me. They are extremely rare around here.


The Thermostat did not have an emergency heat setting which is what thru me off in the 1st place and when we turned on the Heat, the compressor started, so there was not sure sign it was a heat pump...Thanks for the reassurance

"... so there was not sure sign it was a heat pump..." I don't understand that sentence. If the compressor started when you turned-on the heat, then yes, it is probably a heat pump.


You could have a heat pump with no emergency heat.
Of course, though, that could leave the house without adequate or sufficient heat on those days when it is cold enough to need that emergency heat.

Help us out here. Your profile says "California". But, California has a huge variety of climates, from snowy mountains to the hottest desert. It would be more helpful if you clarified in your profile with the name of a city so we can know a bit more about where you are and the area you inspect. This is helpful in many questions in addition to heat.

"Emergency Heat" is electric resistance heat (like a toaster) and may not be necessary. For example, some areas of CA (San Diego, Los Angeles, Santa Barbara, S.F./Oakland area) would probably not get cold enough to warrant the electric resistance heat coils. The heat pump might be fine on its own, depending on the local climate.

[Fred Herndon]

No one has mentioned that he could be looking at an electric furnace and A/C. In which case there would be no emergency heat setting (since it is running on strip heat anyway) and you wouldn't find a reversing valve in the condenser, either.

I still think the most likely answer is that someone installed the wrong thermostat. Or it could be a Nest thermo that doesn't show an emergency heat setting.

Why not just google the make and model # and see what you can find out that way?

[Jerry Peck]

No one has mentioned that he could be looking at an electric furnace and A/C. In which case there would be no emergency heat setting (since it is running on strip heat anyway) and you wouldn't find a reversing valve in the condenser, either.

The original post explained that away:

... the Compressor turned on when I turned the heat on, ...

[Fred Herndon]

The original post explained that away:

Ahh, I didn't read the OP closely enough. So, either heat pump with no strip heat or a wrong thermostat.

[Gunnar Alquist]

I guess it's not that important. It's been three days since he's posted.

[Ralph Stakely]

All, I just have to tell this story.
During an inspection, I asked the client if he knew the difference.. Heat pump, A/C furnace..
No, he said.
OK .. Pointed out on the thermostat the "emergency "heat setting.
Explained that on the " normal" heat setting his heat would be from the heat pump unit.

But even in the Atlanta area we do get some cold winter nights. So,, if the heat pump was just not giving him enough heat, switch to the emergency heat position. That would turn on the gas furnace located in the garage..
But after you get your house warmed up to a comfortable temperature, don't forget to turn it back to the "normal" setting, or you will be continually using the gas heat...

OK fine.
Couple months later, I get a call from my "client." We had had a week or so of cold, rainy, icy weather.
He said his emergency heat was not working as I had explained to him. It was too cold in the house, so he tried the emergency heat. He said he had tried 3 or 4 times, but still no heat. The furnace would just not fire up.
Now, here I was, getting myself ready for a cold trip to check his furnace... (Yes, it was working fine when I inspected it, and I know it's not my responsibility to go check) PR, unknow.

Anyway, before I could say, give me a little time, and I'll come check it.. he said, " I called the power company (electric) and they said they would get the power back on as soon as they could."

I snorted my Ga. sweet tea all over the floor, tried to keep from laughing out loud.
I finally composed myself enough to ask if he had a friend or family he could stay with till they got the power restored.. Then try again, and give me a call if it still didn't work..
Thankfully, I never heard from him again.
BTW, I am enjoying my retirement. Y'all have a great day.

[ROBERT YOUNG]

Hm.:confused: I guess using the model number complicates things? Lol.

[ROBERT YOUNG]

Guys / Gals -
A: I know there is a difference in the operation between HVAC units and Heat Pumps, but is there any easy visual way to tell the difference ?

B: I am just looking for an easy visual way to tell the difference from the outside of the unit.

TIA
Features in Bold, are mine.
A: The only 'real difference' is that a heat pump can reverse itself, the refrigerant direction, so it can provide heating from the evaporator and cooling at the condenser when temperature limits is/are set.
B: 1: Refer to previous post.

An Air Handler may have Heat Strips. Heat Strip Breakers, OCPD, on the cabinet would be the emergency heat you are referring to, but not necessarily.

Might be a (dual energy) HVAC system.
Dual fuel, or hybrid heating systems, feature a heat pump and gas furnace instead of the two more common systems. A heat pump and an air handler, and an AC and gas furnace.:D

Personally, I read/refer to any labels on the equipment when I am back in the office.
Hope that helps.

[Nick Ostrowski]

Easiest way is to look for a reversing valve inside the condenser.

[Elizabeth Chambers]

Easiest way is to look for a reversing valve inside the condenser.

Does anybody happen to have a pic of a reversing valve for reference here?

[Gunnar Alquist]

Does anybody happen to have a pic of a reversing valve for reference here?

Eliz,

Here you go.

[Dom D'Agostino]

Inside view...

[Elizabeth Chambers]

Eliz,

Here you go.
Gee thank's Gunnar, I do realize now that the pic I requested and you provided was included in the OP's pics. duuuuh
I have a wonderful word for you- try "Obsolescent".

[sprsun]

Thanks to a reversing valve in the outdoor unit, a heat pump can absorb heat energy from outside air, even in extremely cold temperatures, and transfer the heat inside the home, where it releases the heat into the air. A heat pump can heat and cool, but an air conditioner cannot, which is the primary difference between the two HVAC systems.

[ROBERT YOUNG]

Thanks to a reversing valve in the outdoor unit, a heat pump can absorb heat energy from outside air, even in extremely cold temperatures, and transfer the heat inside the home, where it releases the heat into the air. A heat pump can heat and cool, but an air conditioner cannot, which is the primary difference between the two HVAC systems.

Thank you.