Al Gore’s attempts to buy  Twitter , the social media darling and soon-to-be public company, in 2009 failed.  But the former Vice President is now an investor with a financial stake in Nest , possibly the hottest Silicon Valley start-up (after Twitter).

The Nest Learning Thermostat is a “smart" product that can digitally adjust the temperature of a room or house on its own; the device learns the patterns of its owners and moves the heat dial up or down depending on whether or not the owner is home (owners can also change the temperature remotely by using a computer or the company’s smartphone app). Gore has a position in the company through  Generation Investment Management , a socially conscious investment and research firm that he co-founded with former Goldman Sachs executive David Blood in 2004.

In an interview with The Daily Ticker, Gore says there “are a lot of great companies out there” but Nest meets the economic, environmental, social and governance criteria that are important to Gore and his team of advisers. Gore’s good friend Tony Fadell, a former Apple ( AAPL ) executive, created the company three years ago. Nest’s thermostats have quickly become a must-have product for environmentalists and individuals who want to lower their heating costs; Nest saves energy and curbs pollution, according to company leaders.

Nest recently launched the Nest Protect, a smoke and carbon monoxide alarm that alerts owners to danger by announcing warnings in a lifelike human voice. Gore says there are many companies like Nest that are shaking up traditional industries by promoting efficiency and utilizing better business models.