An HVAC guy just installed a Carrier 13 SEER heat pump, model number 25HBR, to heat/cool (forced air) the upstairs (10 ft ceilings) of my house (2800 sq ft) in the Washington DC area. The downstairs and basement are heated/cooled by a gas furnace/AC system. So far, I'm disappointed that the heat pump doesn't heat very well. When the temperature dipped below 30F at night, it took two hours in the morning to raise the upstairs temperature from 60F to 66F. The HVAC guy said that heat pumps work that way: they take a long time to heat, unlike the downstairs gas furnace. I've adjusted baffles and had him check the exchanger pressure (OK), fuses, etc , but the heat pump still takes a long time (hour or more) to raise the temperature from 59 to 66 the morning after modestly cool (<40F) nights. Is this to be expected? ILS^2

hvac1000

Heat pumps take a good amount of time to raise temperature. I never recommend a set back thermostat be used with a heat pump. Never expect a heat pump to heat as well and as fast as gas so you might as well adjust to the situation.

Many years ago when a customer would complain about how long the heat pump took to heat up we just used to bridge in a 5 kw heat strip to run with the heat pump. It solved the slow heat problem but did not help the electric bill.

Since we are not there to run a actual test on your system you will have to trust the dealer you chose to do the work. I am sure you got 2 or 3 estimates and checked out how good the companys work was before you hired them.

ilsils

hvac1000,
Thanks for the honest reply. I didn't realize the HP's limitations to heat. From a comfort standpoint, I might have been better off with a bigger furnace/AC, more ducts, etc . . . Will I have the same problem when it's hot, i.e., will the AC stop cooling when it gets above 90F? ILS^2

T-Top

To raise the temp from 60 to 66 with the out side temp of 30 will take along time. you are not saving any money on your electric bill from setting the thermostat back when its that cold outside. Its going to cost you less if you set your thermostat at a temp and never touch it. The heat pump is set up for a more constant temp. But if you set it at 66 and keep it. It should be 66 in your house and you will save you money. Average supply temp of your heat pump will be around 98 and it should heat your house fine if you dont play with the thermostat a lot.

hvac1000

The AC will not stop cooling but you will have a recovery problem if you play with the thermostat. Up stairs are always hotter than down. Cold air will also fall down to the next level. Set the upstairs at a comfortable temp in the summer and let it be. Now you can play with the settings but remember the AC is more for moisture removal than cold air. The longer a AC runs the better moisture removal it will have.

letmetellu

Heat pumps should have an external thermostat that turns the heat pump off when the outside temp gets to 35 or 40 degrees and switches on the axulary heat source.
Another thing about heat pumps it that the air coming out of your registers will be around 95 degrees but the air coming out of the registers when using the axulary heat source will be around 110 to 125 degrees.

ilsils

Thanks to hvac1000, T-Top and letmetellu for enlightening me about heat pump operations. But doesn't that go against good 'energy conservation' procedures? For the past 10 years, to 'conserve energy,' I've been using a programmable thermostats on my furnace to regulate the temperature 4 times daily: set back the temperature at night to 60F, up to 66F before going to work, down to 62 during the day, then up to 66 for an hour or two before bedtime. Ditto with summer AC procedures. Is there a compromise between HP efficiency and 'green thinking?' ILS^2

hvac1000

(((Is there a compromise between HP efficiency and 'green thinking?' ILS^2)))

Yes Turn off the unit and freeze.

Missouri Bound

I have a heat pump myself and yes it does take a while longer to raise the temperature after set back. But it usually averages no more than 5 degrees a minute. I wonder if your house is in need of more insulation, better windows, etc. Heat pumps certainly don't put out the heat of gas units, but then again if the house is adequately sealed and insulated the heat pump should take care of your heating needs. And as far as set back, this is the first year I have used a set back thermostat....mostly for the reason I prefer it to be cooler at night, when I sleep. I doubt I will use it for the cooling season. Another thing to consider is that some thermostats will call for aux heat if there isn't a heat rise in a certain period of time. Does your thermostat provide that feature? Does your furnace have aux heat (2nd stage)? Any heat pump installed in areas that can get below freezing have to have that feature, for the simple fact that during defrost cycle the aux heat is needed to prevent the house from being cooled. Hope I have helped in some way.

Missouri Bound

I need to correct my last post....in error I said 5 degrees a minute....it should have said 5 minutes for one degree. I am very sorry.