when you think smart thermostats, you think Nest. These little guys learn and adapt to your behaviors, adjusting the temperature accordingly. For example, if you want to come Home to a cool house but don't want to run your bill up by leaving the AC on all day, you can have Nest remember to turn on the cold an hour before you get home. (It's convertible with most HVAC systems but you can check yours here.) Nest's app even shows you your energy history to see how much you've saved in the past. Read more...