Even when turned off, electronic and IT equipment often use a small amount of electricity. U.S. households spend approximately $100 per year to power devices while they are in a low power mode — roughly 8 percent of household electricity costs.
Nationwide, it is estimated that standby power accounts for more than $11 billion in annual U.S. energy costs! Using a power strip for your computer and all peripheral equipment allows you to completely disconnect the power supply from the power source, eliminating standby power consumption and cutting carbon pollution.
More tips: http://www.epa.gov/earthday/actonclimate/