Since I have a Nest (and love it), here's the scoop: It doesn't have to be connected to the internet at all. It would work just fine as a standalone thermostat. Most of the functions would be harder to use (only so much you can do when you have 1 button and a wheel), but as far as I can tell they're all there. The web access provides an easier-to-use interface to the Nest. I don't use it much - it did a good job of learning my schedule, so mostly I use the web interface to turn stuff on at the airport after trips. There's some reporting and statistics, but those are mostly fluff.