Smart home thermostats are becoming quite common and, for the Nest at least, downright popular. But most of these systems only monitor from one direction—that is, the user remotely checking the home. The new Ecobee 3 system, however, works both ways; the device is watching its watchers with remote sensors. The Ecobee 3 from same-named manufacturer is designed specifically for larger homes with more than one room. The sleek base unit, replete with a 3.5-inch capacitive touch screen, is augmented by an array of Wi-Fi connected remote sensors. Each of these sensors continually monitor the temperature and occupancies of each room, adjusting the temperature whenever it detects someone arriving or leaving the premises. This behavior is not unlike that of the smart Alba bulbs from last week that adjust their luminance based on the number of people in the room.