There's nothing wrong with trying to save energy and lower your power bill, but unplugging your smartphone, tablet, and laptop chargers when they aren't charging isn't doing much. They're not the energy vampires some people think they are.
Photo by trenttsd.
If you've ever wondered, "how much is it costing me to leave my charger plugged in?" Chris Hoffman at How-To Geek has your answer: next to nothing. Using a Kill a Watt meter, Hoffman tested chargers for the iPhone, iPad, MacBook, Chromebook, Windows laptops, Android phones. Individually, each charger rang up a big 0.0 watts of power usage. Then, just to be thorough, Hoffman filled an entire power strip with six different chargers and got a total reading of 0.3 watts.
Assuming you had the highest cost of electricity in the country, it would cost you less than a dollar to leave them plugged in for the entire year. And that's assuming you never unplug them at all for travel or moving around your home over the course of the year's 8760 hours. So go ahead, keep your chargers plugged in if you want. That being said, there are still some energy vampires around your home you should keep an eye out for. Also, everything changes when your charger is actually connected to your device, so it's still not a good idea to keep your devices perpetually charging. The whole experiment is worth a read, so check it out at the link below.