What temperature should I turn off my heat pump?

I don’t have a heat pump, but isn’t your thermostat wired to engage the auxiliary heat strips automatically to maintain the temperature set point?

If your backup heat is electric strip, never turn off the heat pump.

I always thought it was around upper 20s.
No idea, though. I've never done an actual KwH study on it.

Thought aux heat strips only kicked on when the delta became too great.

As far as I can tell mine has no way of knowing the outside temp.

Assuming you are talking about an air sourced heat pump, since that is the most common by far and what people generally mean when they say heat pump.

40 degrees is the temp where the efficiency starts to decline. But with aux heating they do still work and can continue to work well below 20 degrees. You system should be set up to kick in the aux heat, don't turn the heat pump off.

If you have a water sourced heat pump, outside temp is not a major consideration, since you are extracting heat from the ground which is much warmer than the air.

quote:

---

I checked my advanced setting. Mine is set to switch at 35 degrees. How does it determine outside temperature?

---

I am not sure what all systems have, some thermostats can have a temperature sensor outside but heat pumps have been around longer than digital thermostats and most would simple use your thermostat to determine the need to use aux heating, think many, if not most, still do. The heat pump still functions but if the temp drops more than a certain amount below your kick on temp it kicks on the aux heat. Stays on until you hit the stop temp.

I do know that some of the outdoor boards have a temp sensor on them now, I think a thermistor most time, and the newer systems may very well use that. And most newer thermostats have an exter temp sensor input terminal so that could be it.

I am sure your installer or service tech could give you that info.

When it gets into the 20’s or low 30’s my auxiliary heat strips cannot keep up . So even though the set temp may be 70, the stat reads a current temp of 64 or 65.
Can I get larger heat strips.?
Solutions.??

I had an old heat pump at my previous home that had emergency coils as well You could flip the thermostat to emergency and it would use those coils rather than the heat pump.