Some homeowners set a minimum fan run time every hour to circulate the air within their homes. This means that even if the thermostat determines that the home does not require additional heat or cool air, it will run the fan for the minimum fan run time. Some users have a minimum fan run time of 100%, which means that the fan is always running.
Problems arise when Flair is used with a minimum fan run time. When the fan runs, the air in the rooms with closed vents does not get circulated. This means that the air in the room might get stale and worsen the temperature balance within the home.
Enabling Enhanced Circulation
To enable this feature, go to Home Settings > Thermostats and open the thermostat drop down:
Under the Enhanced Circulation Mode, there are three options:
- Disabled: Vents will operate normally, and may be closed even when the fan is running
- Vents in Active Rooms Only: Vents in Active Rooms open when the fan is running
- All Vents: Vents in all rooms open when the fan is running
Enhanced Circulation Details
If Enhanced Circulation is enabled, vents will open as long as the thermostat's operating state is idle or fan. This approach reduces the amount of open/close operations at the vent and hence does not drain the batteries as quickly.
Enhanced circulation uses the operating state from the thermostat's API to determine if the fan is running or if the system is idle. However, depending on the software architecture of the thermostat's API, there may be a delay between the operating state reported by the API and the actual physical state at the thermostat. For polling-based thermostats, this might result in:
- Flair detects the operating state is fan late, so the vents remain closed for a while even when the fan is already running
- Flair detects the operating_state is heat late, so the vents remain open for a while even when the thermostat is already heating
Note that this is a transient issue and the vent should be open/closed as expected after a few minutes.
Recommended Minimum Fan Run Time
You do not need to set a minimum fan run time. Generally speaking, most systems will run the fan between heat/cooling cycles, allowing Flair to open Vents for enhanced circulation.
If you do set a minimum fan run time for your smart thermostat, we recommend you set it no shorter than 15 minutes per hour.