Have HVAC Questions? Ask an HVAC Expert for Answers
At what outside temp, do you shut off the heat pump and go to emergency electric heat?
You should never have to "turn off" the heat pump. A heat pump will lose some efficiency when the temp gets below the 30's, but it still should put out heat. The auxiliary heat (electric) strips will kick in if the heat pump is not holding the temperature. This is all handled through the thermostat, if wired properly. Let it run, if you see the "AUX" or "Emergency" lights light up on the the thermostat, they are coming on to assist the heat pump hold the set temperature or if the heat pump is in the "defrost" (de-ice) mode. The heat pump is fully equipped to de-ice itself when required and run at maximum efficiency. Don't be surprised to see steam coming from the outside unit, if it's in the defrost cycle.