If you shut everything off how can you get savings? Yet, you have to shut some off for Shabbat. Could someone make an app that turns these off on Friday afternoon and on Motzai Shabbat?
What makes the difference is the prevention for over compensation with heating temperature...the nest thermostat spends a week or so studying how long it takes your heating system to get to the desired temperature. using that information, and the schedule you have set up, it will begin heating (cooling too) in advance of the desired time and temp (i.e. 6am it should be 72 degrees) to ensure that at the desired time, it is the desired temp. Using other thermostats, people have the tendency to overcompensate and set the thermostat at 75 to get the house to the desired 72 faster....
I hope this made sense...