Did you know that when you unplug your cell phone from its charger, the charger is still drawing power? The same goes for your laptop computer, your iPod, and many more of our digital devices that have rechargable batteries. It may be a small amount of energy for each device, but over time this bad habit can slowly add up to a lot of wasted energy.
Let's just look at cell phones, of which there are an estimated 190 million in the United States. A quick back of the envelope calculation says that the combined stand-by usage of all those cell phone chargers, each drawing a measly watt, could add up to 190 megawatts per day. That's enough to power approximately 100,000 homes.
Via: Matter Magazine