Our heat pump is about 30 years old and works fantastically when the temps are above about 40°. Anything below that for a sustained period of time is when it's a problem. We keep the thermostat at around 63° during the day (60 overnight) and the sun helps keep things warm. About 65-67. 

We had lows from 10-18° starting Thursday and never got above freezing for highs until yesterday. It was also overcast so we had no sunshine to help warm us up. The heat strips, we call them the Blue Light Special, came on often in the morning hours. 

The money we thought we saved during the four day power outage got totally nullified by the five day frigid snap we just had. I'm 99.9% sure the heat pump is not as efficient as newer ones but it does well as long as we don't have crazy cold temps like we just had. My hat's off to Trane. They built a beast that has survived 30 years of rain, hurricanes, freezing rain, ice storms, snow, frigid air, extremely hot and humid days, etc.

---

(12-28-2022, 03:14 PM)jagibelieve Wrote:

(12-28-2022, 01:17 PM)homebiscuit Wrote: The resistive heating coils are called Emergency Heat and will show on the thermostat if energized. At least on my system. I haven't seen it, so far. I'm truly curious how low the temperature has to be outside before it kicks on. However, I don't go crazy with the thermostat. It gets set to 65 at night and bumped up to 68 or 69 in the morning.

I could be wrong, but I believe that the "emergency heat" coils won't turn on unless there is a large swing/demand from the unit.  Say your thermostat says that it's 60 and you ask it for 75.

Ours turns on when the unit is no longer putting out warm air, or when we bump it up a hair. It's not digital so it's easy to bump to too much. I've asked hubby several times to put up a digital thermostat but he doesn't see the point. *sigh*

---