Most people don't think too much about all of those green LEDs around their homes or businesses for computers, cell-phone chargers, fax machines, copiers, printers and other electronic equipment. But these silent green eyes are indicators of what's called “vampire power” — standby power consumed by electronic appliances while they are in a standby mode. Another common power thief is the humble power adapter, because it doesn't have an on/off switch.
According to www.wikipedia.com, desktop computers left on will draw around 150W continuously, laptops consume less than 50W while on standby power. Some studies have shown that up 8 percent to 13 percent of residential power usage is consumed needlessly by standby power.
According to the U.S. Department of Energy, “Many appliances continue to draw a small amount of power when they are switched off. These phantom loads occur in most appliances that use electricity, such as VCRs, televisions, stereos, computers and kitchen appliances. In the average home, 75 percent of the electricity used to power home electronics is consumed while the products are turned off. This can be avoided by unplugging the appliance or using a power strip and using the switch on the power strip to cut all power to the appliance.”