What is Energy Star?
ENERGY STAR is a joint program of the U.S. Environmental Protection Agency and the U.S. Department of Energy helping us all save money and protect the environment through energy efficient products and practices.
ENERGY STAR results are already adding up! Americans, with the help of ENERGY STAR, saved enough energy in 2009 alone to avoid greenhouse gas emissions equivalent to those from 30 million cars — all while saving nearly $17 billion on their utility bills.
Currently, the ENERGY STAR label can be found on products in more than 35 product categories. The qualifying products offer a homeowner considerable savings: a home fully equipped with ENERGY STAR qualifying products will operate on about 30 percent less energy than a house equipped with standard products, saving the typical homeowner about $400 each year!
Just look for this logo:

Information provided by: http://www.energystar.gov/index.cfm?c=about.ab_index