Standby power: how much appliances use when off but plugged in, and which to unplug

What standby power is

It’s the electricity an appliance uses when it’s switched off or not doing its main job: the TV turned off with the remote, the microwave showing the time, the charger plugged in without the phone. Lawrence Berkeley National Laboratory, part of the U.S. Department of Energy, which has been measuring it for years, admits the line isn’t always clear: showing the time is an alarm clock’s main function, but not a microwave’s.

That’s why these appliances are sometimes called “energy vampires”: according to the same lab, the name comes from the little black power adapters, which have “two teeth” (the plug pins) and “suck” electricity all night.

How much it adds up to in a home

Lawrence Berkeley Lab admits nobody knows for sure, but estimates it’s typically 5 to 10% of a home’s electricity in developed countries, and a growing share in developing countries, especially in cities.

The sum is simple: 1 watt on all year is about 9 kWh (1 × 24 × 365 ÷ 1,000 = 8.76). An appliance using 5 W on standby around the clock is about 44 kWh a year. None of them uses much on its own; the problem is that a home has dozens.

The good news is that new appliances use far less on standby. According to the European Commission, in 2020 a new appliance sold in the EU used 1.9 W on standby on average, compared with the 3 W it would have used without the rules. Since 2025, the appliances covered by the EU rules may not use more than 0.5 W on standby, or 0.8 W if they show a clock or other information.

The biggest standby users

Lawrence Berkeley Lab publishes a table of what it measured for each type of appliance. Here’s part of it; the median means half the appliances measured used less and half used more.

Look at the last column: there’s a big spread within each type. A modern TV may use almost nothing on standby, another 24 W. You’ll find them all, and more, in the standby power calculator.

An example with numbers

A home with a TV (0.95 W), set-top box (8 W), games console (1.7 W), microwave (1.5 W), desktop computer (2.7 W), printer (2.61 W) and two plugged-in chargers (0.52 W each), using the lab’s medians:

• They add up to 18.5 W on standby.
• If they sit unused 20 hours a day: 18.5 × 20 × 365 ÷ 1,000 = 135 kWh a year, about 11.3 kWh a month.
• At 0.20 per kWh, that’s about 27 a year in your currency.
• The set-top box alone takes 8 × 20 × 365 ÷ 1,000 = 58.4 kWh: almost half.

That’s what the calculator shows when you open it; swap in your own appliances and hours.

What’s worth unplugging, and what isn’t

Lawrence Berkeley Lab’s advice:

• Unplug what you don’t use often: the VCR, the stereo in the spare room, the printer you use once a month. The older the appliance, the more you’re likely to save.
• Use a switched power strip for groups of appliances that go together, like the TV with the set-top box and console, or the computer with the monitor, printer and speakers: you turn them all off at once.
• When shopping, look for low standby products; according to the lab, ENERGY STAR certified products use less.
• Measure yours with a plug-in power meter to see which ones are worth tackling. The lab warns that below about 1 W readings get less accurate.

And what you shouldn’t unplug: anything that needs to keep working, like the fridge and freezer, smoke, carbon monoxide or security alarms, and the router if you need it for your phone line or cameras.

A power strip is for small appliances: big ones (fridge, washing machine, air conditioner, space heaters) go straight into the wall. If you’ll plug several in at once, check it can take them with the power strip calculator.

What to expect, without exaggerating

The lab itself is candid: a determined effort to cut a home’s standby use brings it down by about 20%, and it admits there are more productive ways to save energy with an hour of work. It’s worth it for the biggest standby users (the set-top box, a UPS, an old stereo); with a 0.5 W charger, the saving is a few cents a year. For what weighs most on your bill, check the electricity usage calculator: the air conditioner, fridge or water heater count for much more.