The Nest Thermostat does. Since 2011, it’s saved over 4 billion kWh of energy in millions of homes worldwide.* Because it learns from you. It gets to know the temperature you like when you’re at home. And turns itself down when you’re away. It even learns how your home warms up or how draughty it is, so it only uses the energy it needs. That’s how the Nest Thermostat saves energy.