We have just moved into a house with a Lennox XP17 heat pump. It has two stages of electric heat strips in addition to the heat pump.
In observing the power bill, I have been astonished at the rate we are going through kWh. I did some more research last night to see if everything is working right, and in the process I discovered that the outdoor unit wasn't running, at all. Yet the air coming out of the vents was very warm, which explained the power consumption. It was about 20 degrees outside last night.
The thermostat (a plain Jane Honeywell non-programmable) only shows "Heat on" and gives no indication that the aux stages are running. Emergency Heat is not on.
I suspected a wiring issue but when I switch to emergency heat, same result.
I checked the thermostat setups too, it is set correctly as a heat pump. Surely HVAC manufacturers and installers don't still think that heat pumps are not efficient below 35 F. Is this a setting on the heat pump or on the air handler, or is this a thermostat problem?