If you have a cellphone, you may use your phone charger so much that you leave it plugged into your wall outlet all of the time, even when the cellphone is not hooked up to it. You may assume it's not using energy when it's not connected to the phone. If you’re concerned about “going green,” or just want to save as much money as possible, it's wise to investigate whether unplugging unused chargers can save energy.
“Vampire” Energy Drains
When you leave a charger or any electrical unit plugged into the wall outlet, it uses energy even when it's not in use. This is sometimes called a “vampire” or “phantom” energy drain. It quietly spins your electric meter, without any benefit to you.
How Much Energy?
Though it is definitely using power unnecessarily, a single charger left plugged in does not use very much energy. The Creative Citizen estimates that taking one charger out can save about 1,000 kWh of energy, or about $20 per year. However, every dollar counts when you're trying to conserve, and when you translate it into national terms the waste is significant. The Union of Concerned Scientists estimates that unplugging phone chargers can save $5.8 billion each year of costs to U.S. households. Also, the Future Forests organization estimates that vampire energy drains account for 95 percent of the power used by phone chargers.
Besides being an energy drain, leaving a phone charger plugged into a damaged outlet can be risky. If the outlet has frequent unexplained power surges or is generally problematic, it may not be wise to leave electrical items like cellphone chargers plugged in there all the time.
If you prefer the convenience of keeping your phone charger plugged in so that you always know where it is, connect it to a surge protector unit instead. Click th surge protector off when you finish, and on again when it's time to recharge. This way you stop the vampire drains while keeping the charger securely in place for use when needed.