Buyer beware, I purchased eight Google Nest thermostats and per Google's direction had On Tech to install them. On Tech is a cable tv installation company that knows very little about HVAC systems. I had to spend over $2400 to have and HVAC company come and properly install the C Wire.
These are the worst products and the support that I have received from Google is awful. Now one unit is registering equipment error and google emailed me to say the "least they can do is replace the unit" but they want to charge me for replacement until the old one is returned and expect me to remove the unit and re-install it myself vs. having a professional.
if you can avoid purchasing the google nest thermostat, you should.