Nest - negative

            The Nest Learning Thermostat learns from the adjustments made to it and uses this information to create a personal schedule of temperature changes.  Once a schedule is created, the Nest will change the temperature on its own, according to its schedule, without anyone having to touch it at all.  I, however, am not convinced that this would be very useful for everyone.  Do you really change the temperature so many times during the week that you need a thermostat to make a schedule and change the temperature for you?  For this aspect of the device to be useful, you would not only need to change the temperature a lot, but you would need to change the temperature at consistent times.

            The Nest also has an “Auto-Away” feature, which is designed to sense when the house is empty and make appropriate temperature changes in order to avoid wasting money heating or cooling an empty house.  I am skeptical of its ability to accurately determine when a house is empty or not.  First of all, the Auto-Away sensor detects motion.  This could mean that if there is a long period of inactivity in the room in which it is located, it could think that nobody is home, even if there are people in another room.  Also, thermostats are not always placed in central areas of a house, but instead are often located in out of the way places such as hallways and corners.  And so again, it could potentially think that nobody is home just because nobody passed in front of the sensors.  Finally, the sensors can mistake the presence of pets for the presence of people.