I feel like this has been discussed before… anyone else notice that their heat pump is struggling to keep temperature up? I have mine set a 70 and every time I look at the thermostat it shows 69 or 68. Outside is about 25 right now.

My two old ones had this problem but not the
"new" 2-year old Trane heat pump running 444sf/ton load
23.7/73.7F out/inside currently at rest

Heat pumps do get less efficient as the outdoor temps get colder. New heat pumps can typically handle lower temps more effectively, so if you have an older unit, it may be struggling to keep up with the volume and temp setting of your home. It may be time to switch your thermostat over to "emergency heat" for a bit which is likely an electric heat strip in the unit as a backup for these conditions.

My fairly new heat pump has been doing fine when it's above around 15* outside. We only keep ours set between 65-68 during the winter, but it's had no problem with that. However, when it got down to single digits last night, it started not staying at 65. From what I read, when it gets that cold, heat pumps operating in normal mode periodically have to "defrost" themselves for a few minutes. During this time, your inside temp can drop a few degrees. I think during this time, they're automatically supposed to switch to the emergency heat to maintain inside temps.
When I manually switched mine to emergency heat, I had cold air coming out of the returns, which leads me to believe that something wasn't hooked up correctly when it was installed this summer. I need to get the company out to check to see why the emergency heat isn't working. Of course, by the time they come out, it will be warm enough that I won't need it anymore.

We had some moisture this morning and the condenser had some ice. I lightly hit it with a heat gun to melt it off. It seems to be working better now.

I'd think You're temps are dropping because it's defrosting, and it switches to cooling with heat strips during that cycle. Mine is set to 68 and will dip down to 65/66 when defrosting and then back up to 68 once it switches back to heating

My heat pump is not heating quite as efficiently with the colder temps, but it still keeps up for the most part. I have my electric heat strips set for auxiliary heat, so those will kick on if the heat pump detects it needs some help to reach the desired temperature.

Heat pumps become less efficient when temp drops under 32

When the temp is below 30, I turn on emerg heat and it can keep the house 68, but the lack of humidity it feels colder.

At this point I can't get the house to 69 or higher

Old School Brother said:

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My fairly new heat pump has been doing fine when it's above around 15* outside. We only keep ours set between 65-68 during the winter, but it's had no problem with that. However, when it got down to single digits last night, it started not staying at 65. From what I read, when it gets that cold, heat pumps operating in normal mode periodically have to "defrost" themselves for a few minutes. During this time, your inside temp can drop a few degrees. I think during this time, they're automatically supposed to switch to the emergency heat to maintain inside temps.
When I manually switched mine to emergency heat, I had cold air coming out of the returns, which leads me to believe that something wasn't hooked up correctly when it was installed this summer. I need to get the company out to check to see why the emergency heat isn't working. Of course, by the time they come out, it will be warm enough that I won't need it anymore.

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I've had heat pumps for several houses and properties, i am not an installer but it's been my experience that heat strips aren't there to exclusively heat your home. Hay I've been told by installers is They all temper the cold when it switches to defrost, and they can augment the heat pump when temperatures are like they are. As such, using it in emergency mode will like yield little more than lukewarm warm or even cool air. My heat pumps have all had between 7,000-10,000 watts of heat strips and I believe that's pretty standard unless you ask for more. My 10k were always staged. My last one had 20,000 watts so it could run by itself and heat fine but it wasn't cheap to use.

My current heat pump, when defrosting pumps out air at a higher rate and it is cool, not even like warm. It's better using emergency mode because the Cfm is dialed back for that. It's possible your installer didn't set the cfm right for the heat strip output you have. That has to be right and it's better to err or default to too much air flow lest you burn them up.

Our house has been at 68 for two days, LoL.

Yeah I will never use emergency heat since im too cheap to heat the house with just the heat strips. I will say that mine must not be set up right though as I have 3 5kw heat strips and it only ever gone straight to using all 3. I've never seen stage 1 or 2 aux heat being utilized.

We're in a new home with heat pumps for the first time and this makes me feel better that not getting above 66 or so in the house is normal.

El_duderino said:

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Yeah I will never use emergency heat since im too cheap to heat the house with just the heat strips. I will say that mine must not be set up right though as I have 3 5kw heat strips and it only ever gone straight to using all 3. I've never seen stage 1 or 2 aux heat being utilized.

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They may not be staged. Personally, when I want heat; I want it right now, so I want all those bad boys cranking! But yeah, they probably just left your system defaulted. They have to read the specs and see that el duderino has a unit with 15kw and set 15kw on the setup so the unit knows what it's using and how to manage it. My air handler at my old hose was defaulted to 5 tons with a 2 ton system so it just blew crap tons of air out the vents. Lol.

I saw a lot of heat pumps up in PA that used propane for the emergency heat. That was the best of all worlds, it seemed, and those systems would keep homes at whatever temp was requested.

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There are people that set their heat to above 70?!

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Yep.

We got rid of a heat pump system years ago and went to propane heat ........a world of difference

Rattler12 said:

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We got rid of a heat pump system years ago and went to propane heat ........a world of difference

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Lol. I am doing the exact opposite. I am tired of paying for propane. I have a heat pump at my ranch house and it works fine so I decided to put a heat pump in the new house we are building.

I think mine just went out today. It's been doing well the last couple of days and keeping that side of the house 68-70F. This morning I noticed it would not get above 63F and the air blowing out wasn't even warm. Luckily I have the unit on the other side of the house to get me by until I can get someone to come take a look at it.

When we built our house two years ago we were told by the HVAC company to switch to emergency heat when temps were forecast to be below freezing for more than a day. Overnight lows below freezing for a heat pump is no problem, but multiple days below freezing switch to emergency heat. We keep our house at 67 in the winter and the emergency heat has had no problem keeping it there and not running constantly to do it. We'll be up to 46 today and close to 70 tomorrow so I'll switch back to the heat pump when I get back home from work and then reassess for the cold temps this weekend.

Also your thermostat has a setting that normally have a temperature variance. So if you set to 70, it may have a +- 2 variance so it considers 68 to be acceptable