C406.2.1 Dwelling unit HVAC controls. HVAC systems serving dwelling units or sleeping units shall be controlled with a programmable thermostat that is configured to automatically activate a setback condition of at least 5°F (3°C) for both heating and cooling. The programmable thermostat shall be configured to provide setback during occupied sleep periods. The unoccupied setback mode shall be configured to operate in conjunction with one of the following:

1. A manual main control device by each dwelling unit main entrance that initiates setback for all HVAC units in the dwelling unit and is clearly identified as "Heating/Cooling Master Setback."

2. Occupancy sensors in each room of the dwelling unit combined with a door switch to initiate setback for all HVAC units in the dwelling within 20 minutes of all spaces being vacant immediately following a door switch operation. Where separate room HVAC units are used, an individual occupancy sensor on each unit that is configured to provide setback shall meet this requirement.

3. An advanced learning thermostat that senses occupant presence and automatically creates a schedule for occupancy and provides a dynamic setback schedule based on when the spaces are generally unoccupied.

4. An automated control and sensing system that uses geographic sensing connected to the dwelling unit occupants' cell phones and initiates the setback condition when all occupants are away from the building.