I have 5 Honeywell TH6110 at the cabin for a 5 zone boiler, so it was a big price tag to begin with but great to be able to turn up the heat well before I arrive since water heat takes a while to heat things up. Most of the WiFi thermostats require the extra C Wire to power the circuit, I had to run new thermostat wiring because the old thermostats only needed 2 wires and you need at least 3. Also in my situation I had to install an extra transformer to power the WiFi circuit, C Wire, I was getting voltage drops with all that draw on the single transformer trying to power the 5 thermostats and kick on the heat. I will also say I like the older Honeywell app verses the "smarter' T5 thermostat. The older app has a web portal as well as the app and you get emails as opposed to just phone notifications.