Nest Learning Thermostat, 2nd Generation, Works with Alexa Works with Alexa for voice control (Alexa device sold separately). Nest saves energy by automatically turning itself down when you're away 2nd generation design - nest is now 20-percent thinner and works in 95-percent of homes with low Voltage systems Auto-Away: Nest saves energy by automatically turning itself down when you're away Auto-Away: Nest saves energy by automatically turning itself down when you're away Auto-schedule: Remembers the temperatures you like and programs itself. Easy install - most homeowners install nest themselves in 30 minutes or less. After that, it's just a matter of changing the temperature 2nd generation design: Now 20-percent thinner and works in 95-percent of homes with low Voltage systems Remote control: Connect Nest to Wi-Fi to control it from your smartphone, laptop or tablet Works with 95% of 24V heating and cooling systems, including gas, electric, forced air, heat pump, radiant, oil, hot water, solar and geothermal. Heating: 1,2, and 3 stages (W1, W2, W3) Cooling: 1 and 2 stages (Y1, Y2) Heat pump: with auxiliary and emergency heat (O/B, AUX, E) Humidifier or dehumidifier (HUM, DEHUM) Fan (G) Power (C, RH, RC) Works with Alexa