Okay, I'm new to this heat pump stuff, always lived in the land of the cold where we used gas to make heat! FIRE! grunt grunt!!!
so, now I have a nambie pambie heat pump on the house, and today for the first time or, last night really, it got below freezing,
26 to be precise, well, the heat pump has been running almost constantly, and from time to time, the AUX heat has been kicking in too. is that normal? The air temp outside is 34 right now, and the air comming out of the vents is 80 About 2 weeks back I had a "disk" replaced, (some type of stat they said) temp outside was probably in the 45 -55 range then, but the air comming out of the vents was closer to 90,
is this normal?? can the heatpump only give me 80 degrees on days were the temp is at or below freezing? the pump is only 5 years old, and at the time the disk was replaced the pressure was checked and it read high.
A heat pump runs most efficiently when the output is as cold as possible while still heating the house, so the air coming out of the registers should feel cold. If you measure its temp, it's warmer than the room. That's what you need.
The airflow is kept very high to achieve this - essentially cooling the indoor coil with indoor air so it never gets hot.
As the outdoor air temp drops, the heat pump does less and less work, and achieves less and less heating; at the same time, the cost to run it drops, so in effect you fall back on resistive heating without any loss of money. In the circumstance where the heat pump no longer holds the house, it will run continuously (not achieving much) while the resistive strips kick in and out.
If the heat pump is broken in some way, say constant defrosting, then this continuous running costs you money. If not, then it's just the way heat pumps are.
Women like warm toasty air coming out of the ducts. Heat pumps don't do that. Guys see the method in it and put up with it.
Sounds about right, pnly thing leaves me wondering is the reference to this "disc"--Oh well, Im not an hvac pro, just that Im fairly familiar with many aspects of their operation.
As outside temps drop to near freezing, a typical heat pump loses capacity, quite a bit--though my numbers are off somewhat, think of it kinda like a
42,000btu unit capacity unit only has 21,000 capacity when operating in these temps. They are still more effecient than straight electric heat as far as overall energy cost / heat produced, because the compressor amperage draw drops also--if you cant provide the heat into the outside coils then the compressor pump runs only partially mechanically loaded.
.PDF document showing performance data for a typical heat pump, the heating capacities start at around page 12 :
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Now, If the outside temps never dropped below about 45 degrees where you live, likely the aux electric heating strips would never come on at all.......generally, they are optional equipment and arent always even installed into a unit from the factory.........
Where you will notice the coldest air being discharged from the registers is probably when the unit goes into "defrost mode"--under cold conditions, ice will form on the outside coil which blocks airflow........to melt this ice, the unit automatically temporarily reverses operation and turns itself into an A/C unit when icing of the coils is sensed, rejecting some heat to the outside from inside of the house--you can tell when this happens, because the compressor on the outside unit will be running but the fan outside will be off......
After a few minutes, the reversing valve click and you will hear the refrigerant go psssttt as internal pressures reverse, and also the outside fan will start up again---wah lah, you are back into heating mode again.......
So, if it werent for them aux electric strips coming on, the air coming out of your registers would be VERY cold indeed during a defrost cycle
I challenge the concept of an heat pump where it gets below freezing. Heat pump reverses the indoor coil and outdoor coil for heating. It is trying to get heat from the outdoors and put it in the home. Not much latent heat at
26 degrees, so that tells me your aux heat, probably an electric element is running. Picture a big toaster in the air handler. Lots of them are installed all over. Gonna cost ya big time if it stays cold like that very long. Rest of the operation described seems ok to me.
Sure sounds like it. We used to have a heat pump; got tired of listening to it run all the time for little effect, so after it broke a second time in two years, went with Propane (all we can get out here). I love the peace and quiet.
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