Nest Labs, which was recently acquired by Google, is a leader in the smart-home space. Its electronic, programmable Wi-Fi-enabled thermostat, released in 2012, was one of the first smart-home products to strike a chord with users. It keeps track of your temperature habits and can learn your preferences.
In addition, the thermostat remembers if you turn the heat down at night and can turn the heat or air-conditioning down automatically if no one is home. And seeing as a change of just one degree can impact your energy bill, those changes could mean sizable savings.