[RELEASE] Enhanced Z-Wave Plus Thermostat Device Handler - Honeywell, GoControl, CT, Linear, Trane, MCO, Remotec

[maddie (Head of Support (rboyapps.com))]

You may want to check our a Venstar system which can add an extra C wire to exiting setup without a running a new wire.

Smart Thermostats Controller for HVAC Wired Air Conditioners

Use a Venstar to convert your 3 wire to a 4 wire system and it should work with these thermostats. You can also consider using a CT-100 Z-Wave Plus thermostat from @TheSmartestHouse

FYR, the IRIS Smart Plug doesn’t act like a reliable z-wave repeater even though it’s capable, rather it is also know to cause issues with the zwave mesh as reported by other folks on the forum.