I'm not sure looking at the pure money saving in terms of lower energy is the way to go, since a lot of the benefits are more intangible than that. The ability

I'm not sure looking at the pure money saving in terms of lower energy is the way to go, since a lot of the benefits are more intangible than that. The ability to detect when you're away, automatic scheduling and easy control from a smartphone are pretty big benefits for me but they'd be hard to quantify in terms of being "worth it". As others have pointed out, you can achieve a lot of that with other (cheaper) products. But to be honest, I think Nest's main strength is making the features easy and fun to use rather than having totally revolutionary new features. But that's the Android and Iphone claim to fame in the smartphone world, and they did OK ;)