While one charger may not use much energy, think about all of the appliances in your home that are “off” — except that is, for the LCD clock on the front. It's not off, it's running day and night.
The power these items pull is called “phantom load,” or more derisively “wall warts.”
Before you panic and start unplugging all your appliances, Grist magazine has some helpful suggestions for lightening the phantom load:
Many of us solve this environmental and financial problem by plugging the offenders into a power strip with an on/off switch. When we are through using the appliances on a strip, we turn off the strip, which cuts the electricity to the appliances. Power strips control the electricity coming from the wall, and when they are off, the power is off to the attached equipment. Then, though the evil appliances wish to continue sucking power from the grid, they are thwarted. Trolling on the web will bring you persuasive testimonials from people who shrank their power use this way.As the price of gas approaches $4 per gallon, investing in a power strip might not be such a bad idea ....
According to the U.S. Department of Energy, around 75 percent of the energy used by our home appliances is drawn while we think they are "off." Typical offenders include microwaves, stereo equipment, televisions, chargers for cell phones or iPods and co., and all the computer equipment.