Energy Star is a joint program of the U.S. Environmental Protection Agency and the U.S. Department of Energy dedicated to helping individuals protect the environment through superior energy efficiency.
Source: U.S. Environmental Protection Agency and the U.S. Department of Energy

Energy Star is the national symbol of energy efficiency. with the help of ENERGY STAR, Americans saved enough energy in 2010 alone to avoid greenhouse gas emissions equivalent to those from 33 million cars -all while saving nearly $18 billion on their utility bills.