Not necessarily true! If your home already has a thermostat, then nest has a website where you answer some questions and they let you know if it can be replaced with a thermostat. Only 4 wires are needed typically.

ATK just did a short video on this. It’s probably not as detailed as you might want but here you go. I believe Teflon is used because it is so innocuous, but the chemicals used underneath to make it stick are very bad for you. https://youtu.be/2RJkIPT-jLs?si=w0X3lpQK9tnaMmbA

Small wordplay and rhymes that come to mind from time to time