Humans aren't the only ones who benefit from sleep; setting your computer to 'sleep' or 'stand-by' mode when you aren't using it could save energy. In fact, the U.S. Environmental Protection Agency estimates that Americans could save 44 billion kWh - or $4 billion - if computers and monitors were to utlize the sleep function on their machines. To add further perspective, the greenhouse gas emissions saved would be comparable to approximately 5 million cars per year.

The EPA has launched the Energy Star Low Carbon IT campaign to educate individuals and companies about the best ways to minimize the environmental impact of computers. Using the sleep function has the potentnial to save users up to $50 per computer each year. Fox Entertainment Group Inc., Microsoft, HP and Dell Inc., are among the participants in the program.

"Although the work day may come to an end, we never clock out of our environmental responsibility," said EPA Administrator Stephen L. Johnson. "By joining the Low Carbon IT Campaign, our partners are taking steps that are not only good for their bottom line, they're good for the environment."

Companies who wish to join the campaign can make a pledge online to enforce stricter guidelines for energy efficiency when using computers.

» U.S. Environmental Protection Agency