Anyone use a heat pump in these cold temps. We live in Missouri and the temps are in the teens and colder. The service people told me to shut off the heat pump and use the strips. It is cheaper to do that than run the pump and the strips. If you know anything about these pumps please enlighten me.
heat pumps
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IndyChris
New member
I run a heat pump system (standard compressor style), and live about your same lat.
From what I understand, they start to loose efficency below 30deg, and basically hit a wall at 0. I notice mine starting to go into defrost mode below 30, so I use a woodstove for heat when its really cold. It keeps the unit from running during the coldest periods.
I would leave it on, and let it decide what to do. Unless you get to where the heat cannot keep up on its own. The emergency heat section is really just that, for emergencys when the compressor fails etc..
Hope this helps some! I have been learning as I go, this is my first home with a HP. Going on the second winter, and even without wood, I always was as comfortable as needed using the thermostat in "Heat" mode.
From what I understand, they start to loose efficency below 30deg, and basically hit a wall at 0. I notice mine starting to go into defrost mode below 30, so I use a woodstove for heat when its really cold. It keeps the unit from running during the coldest periods.
I would leave it on, and let it decide what to do. Unless you get to where the heat cannot keep up on its own. The emergency heat section is really just that, for emergencys when the compressor fails etc..
Hope this helps some! I have been learning as I go, this is my first home with a HP. Going on the second winter, and even without wood, I always was as comfortable as needed using the thermostat in "Heat" mode.
moeh1
Gold Member
I am looking at one of the high end ones for myself. 36k BTUS of heat in warmer weather, but it drops with temp - half that at 7 degrees and the scale only goes to 2 degrees, where it is about 1/3. So when you need the most heat, the strips are going to be at least sharing the load. If the unit isn't complianing, I guess you are still ahead of all electric heat on the utility bill.
Bird
Epic Contributor
I can't claim to know much about them, but this is our second winter in a house with a 1999 Rheem heat pump. We just leave the thermostat alone and let it do its thing. I did try the "emer" setting once just as an experiment and it did heat up fast and put out lots of hot air, but so far the heat pump setting has kept up even when it got down into the teens. I really don't know just how much of the time both the compressor and the heat strips were working. I was visiting with the next door neighbor this afternoon and the last two months we've had almost exactly the same electric bill and our house is more than 20% larger than his, we're running two refrigerators to his one, our dog is in and out enough that I know our doors are open more frequently than his, and I know our TV is on a great deal more than his. So I guess maybe the heat pump is more efficient.
Modern heat pumps will work fine down well into the single digits. As it gets colder, efficiency drops a small amount, but the capacity (BTUs) is what starts to fall off. This necessitates the need for supplemental heat, such as electric strips. This can be somewhat overcome by putting in a larger unit, but then cooling can be a problem. Again this is improved by having a two stage unit.
Even at 0 degrees, the heat output will still exceed the electrical input in watts (more efficient than strips) but some supplemental heat will be needed. Last but not least, do not use a night setback thermostat. The warm-up in the morning will force the heat strips to come on and it will kill the efficiency of the system. Over 30% more power is used overall when a set back is used. Set it and forget it, and it will operate most efficiently.
paul
Even at 0 degrees, the heat output will still exceed the electrical input in watts (more efficient than strips) but some supplemental heat will be needed. Last but not least, do not use a night setback thermostat. The warm-up in the morning will force the heat strips to come on and it will kill the efficiency of the system. Over 30% more power is used overall when a set back is used. Set it and forget it, and it will operate most efficiently.
paul
ctpres
Gold Member
heat pump notes from SE texas. Air flow/volume much higher and air duct temp not a lot higher than room temp. Might seem drafty to some folks. Air handler run time much longer. With high humidity I had to increase outside unit defrost cyle to prevent icing of coils. Advise neighbors that you have heat pump as defrost cycle can result in a lot of steam/smoke looking clouds. My neighbor woke me up the first time he saw it/thought outside unit was on fire. If anyone in family is prone to constantly adjust thermostat-forget heat pump. Saves Money-Yes
Bird
Epic Contributor
Yep, the service man I paid to check out this system before I bought the house said the heat strip will come on anytime you raise the thermostat setting more than 3 degrees at a time.
I have a cousin who used to live in this area in a house with a heat pump. He said he didn't like it, just for that reason. When it first comes on, it seems like it's blowing cool air for awhile.
It's certainly different from what we've had in the past, but we like it.
mechanic said:
As I type this, it is 21 deg F outside and there are two heat pump units running on the other side of the wall from me.
You should not have to do anything to turn the heat strips on or off. Our last house had a York unit that had a temperature sensor that shut off the outside unit automatically when the temp got down below 20F or so. These Lennox units don't seem to have anything like that, so they run all the time.
Heat pump houses (this is our second) are considered drafty and cool by a lot of people's standards. The air coming out the floor registers is nowhere near as warm as a gas furnace; I'm going to guess it is something like 80-85F air. So consequently, if you feel 80F air on your 98F skin, it feels cool. But they are economical to run. I'm heating and cooling 3400+ sq ft with dual Lennox units and our total electricity bill (lights included) is averaging less than $130 per month year round. But a lot of that is due to better insulation because the York unit cost about the same thing to heat/cool our 1600 sq ft house.
I'm over in Kansas so have about the same weather as you.
kenmac
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I have a cousin who used to live in this area in a house with a heat pump. He said he didn't like it, just for that reason. When it first comes on, it seems like it's blowing cool air for awhile.
Bird, where your duct work is located & how it's insulated plays a part in this . Like others have said , leave the unit on & let it switch it's self over. Unless, you have a thermostat that isn't functioning properly. Which, I have seen the electronic t.stats go bad
Bird, where your duct work is located & how it's insulated plays a part in this . Like others have said , leave the unit on & let it switch it's self over. Unless, you have a thermostat that isn't functioning properly. Which, I have seen the electronic t.stats go bad
mjarrels
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I have a trane two an a half ton heat pump and rarely see a blue lite (electric backup) On very cold days like today, it does run alot but still blows warm air. My two biggest dislikes are the expected life of the system and it dries everything out including me. I also have a Harman coal stove (burning right now) for backup and when you just want to feel raw heat. But at $192.00 a ton for hard coal, it is cheaper to use electricity for day to day. I don't ever change the temp setting for heating/cooling except for rare occasions (just spend two months in the Phillippines and set it back 10 degrees).
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