DIY: How To Be Computer Smart
Like anything else, computers use a lot of energy. Save wasted energy by turning all your electronic devices such as computers, laptops, and tablets off before you go to bed. You may find it easier to turn off your computer every night by hooking up everything (the computer, printer, scanner, etc.) to one power strip. During the daytime, you can set your devices to hibernate when they are not being used to save even more energy.
Referenced from: Mother Earth News