[lsllc]

The higher end "smart" models tend to use proprietary thermostats so you can't use your Nest/Ecobee. Kind of annoying ... I just replaced an old system with a Trane XR15 heat pump with aux heat incl. new air handler ($6K all in, incl. install and permits) but want to stick with Nest because I'm already invested in that ecosystem.

Too bad there isn't a common standards based protocol (e.g. something like MODBUS) for interfacing across climate control devices ... instead of either the std. 6 conductor 24v thermostat wire or a proprietary interface as I don't think this supports features such as variable speed fans on the air handlers.