Hi, I have a smartapp called ecobeeStateTriggerHA which allows you to choose an Ecobee’s thermostatOperatingState (ex. Fan Only, Heating, Cooling, etc.) for triggering a switch.
You may want to check it out.
See the documentation here:
http://thingsthataresmart.wiki/index.php?title=EcobeeStateTriggerHA
It’s available with the github integration along with other “complimentary” smartapps:
N.B.The smartapps only work with My Ecobee device, the most comprehensive & resilient ecobee-ST integration. I ask for a small contribution given the amount of work for design, coding & testing.
http://thingsthataresmart.wiki/index.php?title=My_Ecobee_Device
Regards.