Flair works with all thermostats! You do not need a smart thermostat to use Flair.
For central systems using an integrated smart thermostat, Flair works in two ways to manage temperature: 1) redirect airflow via Smart Vents, and 2) optionally control a smart thermostat.
For central systems using a non-integrated thermostat, Flair will manage temperature by redirecting airflow via Smart Vents. Additionally, when using Auto Heat/Cool mode, Flair will read the duct temperature to know when the system is heating or cooling.