Heat Pump or not

[apolillo]

Fellow Inspectors,
Last week I had townhome with all electric hvac. I wrote up that the condenser unit was a heat pump (reverse valve visible) and the t-stat did not have the option for emergency heat. The unit did not operate in heating mode. Today I was back to view a number of items including a new roof. The seller showed me the sales contract for the unit. It stated that the system had be sold as AC only and Electric furnace.
I informed my client that while the unit does operate, she could probably save a chunk of change, by having system checked by her choice of HVAC contractor, to see if she could take advantage of the heat pump option.
Have any of you seen a similar installation ???

Anatol

[Brian E. Kelly]

If it gets cold there in Maryland Anatol running the heat pump is not the answer. Better off running the electric furnace IMO.

[rcooke]

I understand below about 32 degrees F the efficency is poor and many switch over to resistant heating ,above 32 is the best gain over resistant heating
some more info here http://www.flex.net/~lonestar/hpumps.htm

Cookie

[apolillo]

I see lots of heat pump systems here. My concern was for my client energy costs. Seems a shame to have a heat pump and not take advantage of it. Winter temps average about 35-40 nightly, so for me it makes sense to have the option.

Anatol

[Robert J. OConnor, P.E.]

Originally Posted by apolillo

I informed my client that while the unit does operate, she could probably save a chunk of change, by having system checked by her choice of HVAC contractor, to see if she could take advantage of the heat pump option.

Good recommendation IMO ... in moderate temperatures heat pumps can be a good option and very efficient. Even in colder regions a HP with supplementary electric heat is better than just electric heat alone (although usually not as good an option compared to a gas or oil fired system) ...

Still scratching my head as to why they didn't set it up as a heat pump (assuming the outdoor unit is indeed a heap pump unit), with the electric as supplementary/auxiliary heat only as needed. Maybe the contractor didn't know how to wire that system ...

P.S. Best way to ID an exterior heat pump unit is to look inside the outdoor unit for a reversing valve (see typ pic attached).

[Doug Edwards, CMI]

Not much of a contractor then. The thermostat comes with installation and wiring instructions. Your call to have an HVAC contractor (only not the same numbskull that installed it the first time) come and set up the Heat Pump correctly is the right call. During milder weather the Heat pump will operate like ....well, a heat pump. When it does get very cold it will operate...well, like a heat pump in Emergency Mode, like it is suppose to. Either way it should be set up properly for all the right reasons. Many of the old assumptions and stories about Heap pumps are no longer the case. We have some periods of extremely cold weather here and there are a bazillion heat pumps as the primary heat source. The Heat pump of today is not the heat pump of 10-15 years ago. If it is an old antiquated POC it is probably overdue for replacement and if new and properly sized for the home it will do just fine, once it is properly wired and the thermostat is actually working as intended.

[Michael R. Boyett]

Originally Posted by apolillo

...and the t-stat did not have the option for emergency heat.

Remember some new t'stats don't have the separate on/off switch for emergency heat like the older t'stats. It is programmable on some of the LCD types. I saw one just a couple of weeks ago and had to research it to confirm that was the case. That was, up to then, one of the ways I quickly identified a heat pump.
Thermostat looked like this: http://nachi.org/forum/attachment.ph...2&d=1164863937

[David A. Andersen]

That t-state does have an EMER setting if used as a five wire aux heat setup.

The only time that you will have a t-state without an em/aux heat setting is if the AHU does not have aux heat strips. These may be found in warm areas like AZ and TX.

[Robert J. OConnor, P.E.]

I think what Mike is saying is that for heat pumps he is used to seeing a manual T-Stat with a switch on the outside that can be moved to the "EM Heat" setting ... like in the attached pic.

Also always take a look inside the outdoor unit when doing the exterior part of the inspection, and look for a reversing valve inside the unit. It should be pretty obvious when you see one (see my post above).

JMO