what should I expect?

I have a goodman airsource HP that is a 13 seer 7.7 hspf 2.5 ton.My question is, what should I expect for a vent temp when it is 3 deg. outside and 67 deg. inside? thanks in adv.

 

It's impossible to say for sure without knowing what auxiliary heat strips are installed inside the heat pump since the heat pump section is doing little or no good at that temperature. They are available in different sizes/powers. The temperature rise you will see depends on which ones are installed in your unit. Generally Goodman offers heat strips 5kw through 20kw in 5kw increments.

Using a accurate thermometer record the temperature of the air entering the cold air return and measure the air right as it comes out of a thermostat closest to the heat pump. What temperatures do you have?

 

thanks I should have said that I have shut the heat strip breakers off so I am only checking the hp capacity here is what I get at the register 71.9 deg. at 65 deg. indoor and 4 deg. outdoor no increase in room temp.

 

unless the ductwork is well insulated or in a heated space, the air temperatures at the registers can be misleading. Did you ever check it when the outdoor temperature was in the 30's ?

Most heat pumps don't pump much heat at 4 degrees - my previous York heat pump, for example, used to automatically shut off and activate the AUX heat at 4 F.

 

I don't know the exact heat rise you should see with that outdoor temperature but it sounds about right. A 7f temp rise when it's 4f outside is actually better than I would expect (and it makes me glad I'm in NC where it's a bit warmer).

This chart is not for your unit. It's just something I quickly found on the web. Ignore the yellow and purple horizontal lines, those are auxiliary heat strips. The red line is how much heat your house needs and as it gets colder (left) you see the heat/energy required goes up. The blue line is what the heat pump produces. As the temperature drops the heat pump can deliver less and less heat.


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thanks, so at around 35 degrees everything works great and that is good because I have a makeshift geo unit set up and I can keep about a 32 -35 deg. constant even at 0 deg. outside I had been working on this retrofit for my air HP and was doing a patent search to see if I needed to protect my idea, and as it turns out it has been done. So I am considering other possibilities with this. Probably the best thing about it is I think I can manufacture and sell for as little as $2000 for a 25000 btuunit. with the system on I was getting an 83 degree register temp. @ 3 deg. out and 65 deg. inside, a 18 degree increase. However @ 20 deg. out and 72 in I can get 95 deg.@ the reg. a 23 deg. increase. and another benefit is ..no need for defrost. thanks again