Furnace, heat pump, or boiler? Identify your system from the thermostat, the equipment label and the outdoor unit, no panels opened.
The 7-10 degree setback rule works on a furnace. On a heat pump it can trigger expensive backup heat. Here is the revised range and why.
Auxiliary heat is automatic. Emergency heat is a manual last resort for a failing heat pump. What each does, and why one is not a setting to leave on.
The outdoor temperature where your heat pump stops keeping up on its own, why it exists, and how it ties directly to your aux lockout setting.
One heat pump setting decides how often expensive backup heat runs. What aux lockout controls, and how to tell if yours is set too high.