Does leaving chargers plugged in actually waste electricity?

A modern charger left plugged in with nothing attached draws a very small amount, typically a fraction of a watt. Over a year that is a negligible cost, measured in pennies rather than pounds. The advice to unplug chargers dates from an era of less efficient designs and has been repeated long past its usefulness.

Where standby consumption genuinely matters is with devices that remain in a ready state rather than truly off. A television that wakes instantly, a set-top box recording or updating, a games console in rest mode, a desktop computer, a network router, and anything with a display or a clock all draw continuously and in some cases substantially. A set-top box can consume nearly as much on standby as in use.

Collectively these can account for a meaningful share of a household's electricity, and that is the part worth acting on. A cheap plug-in energy monitor identifies the real culprits in an afternoon and is more productive than unplugging phone chargers.

There is a genuine caveat to the general advice. Devices that need to remain available, such as a router, or that suffer from repeated power cycling, should be left on. And smart home equipment is generally useless if switched off at the wall.

The higher-impact energy decisions in a typical home are heating, hot water, and anything that produces heat: ovens, kettles, tumble dryers, immersion heaters. A single hour of electric heating exceeds a year of standby draw from a phone charger.

Unplugging a charger is harmless, it simply is not where the savings are.