The Energy Star Low Carbon IT Campaign encourages businesses to put their computers to quote "asleep" when not in use.

Activating the power management - or sleep mode - on computers and monitors will help reduce electricity while also saving money, the EPA says.

According to the agency, putting office computers and monitors to sleep when not in use would save the U.S. nearly four billion dollars worth of electricity each year. That's the same as preventing greenhouse-gas emissions equivalent to those of about five million cars.

The campaign is being launched in partnership with the Climate Savers Computing Initiative - made up of technology firms, energy companies and nongovernmental groups working to promote the use of more energy-efficient computers.