Nest has made a few minor updates to its Learning Thermostat, following earlier changes to the Protect and Cam. The third-generation Thermostat is thinner than earlier models, and uses a larger 2.08-inch diameter 480x480-resolution display. New features included in this version are Farsight, where the device lights up and shows the temperature or time when someone walks into the room, and a Furnace Heads-Up warning on the display and smartphone at the start of a heating or cooling session if it notices potential problem with the furnace. On sale today, the third-generation Nest Learning Thermo
