Photo: Mikki Beymer/iStockphoto

You already turn off the lights when you leave the room. What about your computer? You may have heard that computers last longer if they're left on—they don't, but they do waste energy. (One study estimated that the computing industry accounts for 2 percent of the world's carbon dioxide emissions.) Set your computer to enter sleep mode after five minutes of inactivity, and turn it off when you're done.

But with many electronics, pushing the "off" button isn't enough. Almost anything with a digital display, a remote control, or an AC adapter draws power even when not in use—and most homes have about 40 such devices. This so-called phantom load accounts for 75 percent of the electricity consumed by home electronics and about 8 percent of total residential electricity use. That's enough to power your house for one month each year.

Many of these electronics are easy to disconnect. Pull your charges out of the outlets when they're not in use, and attach other energy suckers to a surge protector and turn the strip off.