Heat pump setback thermostat
I have used setback thermostats for many years, but now I live in a home with a heat pump rather than a gas furnace. I understand that setting back the thermostat, then calling for heat will energize the emergency / auxiliary heat. Is the savings obtained by setback enough to overcome the resistance heat? Is it feasible to control the resistance heat with an aux. thermostat to prevent it from coming on unless the outside temp is too cool for the heat pump alone to heat the house?
I appreciate any advice... thanks.