Thermostat fan cycler for stale air

Does anyone have an example for a rule that cycles the HVAC fan after so many minutes while the HVAC is inactive ( not cooling or heating )? I assume a countdown timer variable must be instantiated and ticked down till cycle time.

Thank you

I think this is a prime use case for "sticky triggers", e.g.

Thermostat changes to OFF and stays for 30 minutes...


Are you looking for a rule that will turn off the HVAC when the temperature of the air coming out is the same as the ambiant air? Would you do this with a sensor near the outlet, or do you have a way for the HVAC to provide this information to Hubitat?

I need to cycle the HVAC fan at least every 30 minutes to keep the air fresh in closed rooms. So if HEAT or A/C is not called for at least 30 minutes, the fan will turn on for 5 minutes.

Sounds like a good use-case for an app.

Ecobee thermostats have this built-in.