Keep your home at the perfect temperature, day and night. There's no need to program this third-generation Nest thermostat: just use it for a week, and it will learn your preferences and heat or cool your home accordingly. It can also be fine-tuned at any moment, either with a twist of its rosy copper ring or a quick adjustment on the free Nest app. The Nest app will also send alerts to your phone if your home gets too cold or too hot, if your furnace is malfunctioning or if it's just time to change the filter. To save energy, the Home/Away Assist automatically goes into Eco Temperature mode when sensors and your phone's location indicate that nobody's home. Daily Energy History reports show how and when you use energy, and the sweet Nest Leaf icon on the LCD display helps you find new ways to save energy. The modern, minimalist copper Nest thermometer looks sleek on your wall, and the easy-to-read display responds to ambient light so it's never too dim or too bright. Program it to display the time, temperature or weather whenever it senses you enter the room. Keep your home comfortably cool or wonderfully cozy while saving energy, money and time.