BTW, I have already several contributors who use my zoned heating/cooling solutions based on any ST connected thermostat and smart vents for more comfort at your home.
My Smartapps can orchestrate your (ST connected) thermostat(s) and vents in such a way that only occupied rooms will receive more airflow inside a configurable zone(s) based on schedules, So, for example, during the day, you can configure the zone(s) to be only for your downstairs & basement rooms.
For more details, refer to this thread:
Regards.