"Vampire power" — electricity drawn by devices that are plugged in but not actively in use — is real, but it's also frequently overstated. Some always-on devices barely register on your bill; a few genuinely add up. Here's how to tell the difference instead of guessing.

Why this happens

Many devices draw a small amount of power even when switched "off," to keep a clock running, stay ready for a remote control signal, maintain a network connection, or keep an internal charging circuit active. Individually, most of these draws are small — often 1-5 watts — but a house with dozens of always-plugged-in devices can add them up to a real, if modest, amount over a full year.

What actually draws meaningful standby power

How to actually measure it yourself

Rather than guessing, a plug-in power meter (sometimes called a "kill-a-watt" style meter) is inexpensive and tells you exactly what a device draws, both in active use and standby. Plug the meter between the wall outlet and the device, let it sit in standby for a few minutes, and read the wattage — this turns a vague suspicion about "vampire power" into a specific number you can actually judge as worth addressing or not.

Where to focus, based on what typically matters

If you want the most impact for the least effort, a game console's power mode and an older set-top box are the two places most homes will find real, measurable savings — everything else on this list is usually a rounding error by comparison.

Quick standby-power checklist