Phantom loads, also called standby or vampire power, are the watts a device uses while it looks switched off. A single one is usually small. The point of hunting them down is that they run 24 hours a day, every day, and they add up quietly.
What you need
One energy-monitoring smart plug, your electricity rate from your latest bill, and about a week of moving the plug around. A power strip helps for groups of devices, as long as the total stays well under the plug’s rating.
Step 1: measure the off state
Plug a device in, turn it off the way you normally would, and wait a few minutes. Note the watts the app shows. Good suspects include TVs and soundbars, game consoles, set-top boxes, desktop computers with speakers, printers, and older appliances with clocks or displays.
Step 2: log a full day
Some devices wake up to update overnight. Leave the plug in place for 24 hours and check the kWh total in the app instead of just the live reading. That number is the real daily cost.
Step 3: turn watts into dollars
Multiply standby watts by 8,760 (the hours in a year) and divide by 1,000 to get kWh per year, then multiply by your rate. For example, 5 watts all year is 43.8 kWh. At an example rate of 17 cents per kWh, that’s about $7.45 a year for one device.
Step 4: fix the worst offenders
For anything that doesn’t need to be ready instantly, set a schedule or an auto-off timer on the smart plug, or switch it off with a power strip. Leave alone devices that need constant power, like a fridge, a router or a medical device. Some plugs, like the THIRDREALITY Gen3, can also alert you to unusual changes in usage.
One more thing: the plug’s own draw
Smart plugs use a little power too. Emporia, for example, lists 1 watt of standby for its plug, and most makers don’t publish a figure at all. If a plug only saves you a watt or two, it’s better used as a measuring tool you move around than left in place.
Want to see how a few smart plugs fit with the rest of your setup? Our Whole-Home Energy Calculator adds up what plugs, a thermostat, an energy monitor, an EV charger and a backup battery would mean for your monthly bill.