Reduce the load before chasing a rating
Thermostat settings directly influence the temperature difference the HVAC system must maintain between indoors and outdoors. Larger differences generally require more heating or cooling energy.
Energy savings from setbacks depend on climate, equipment type, duration and how the system recovers. A schedule should reflect actual occupancy rather than an arbitrary number.
Heat pumps deserve particular attention because aggressive recovery strategies can engage supplemental electric heat depending on system design and controls.