Standby Power Explained: What Phantom Load Really Costs and How to Cut It

Standby power is the electricity a device keeps drawing when it looks switched off or is waiting to be used: the TV that wakes from the remote, the console that downloads updates overnight, the microwave clock. Modern devices often draw around 1 W or less in standby, but older or networked kit can draw much more, and it runs 24 hours a day. Every watt of constant standby costs about £2.31 a year at the current UK price cap rate, so it is worth finding the few devices that waste a lot, rather than unplugging everything.

What counts as standby

"Standby" covers several different states, and the difference matters when you measure:

• Off mode: the device is plugged in and switched off, but still draws a trickle (often for a power supply or a soft-touch button).
• Standby: the device can be woken by a remote, a timer or a button, and may show a clock or a light.
• Networked standby: the device stays connected to your network so it can be woken by an app, a voice assistant or a message. Smart TVs, consoles, printers, smart speakers and routers often sit here.
• Idle or low-power mode: the device is technically on but not doing much, such as a desktop computer with the screen asleep or a set-top box between recordings. This can draw far more than true standby.

The term "phantom load" usually lumps all of these together: power used while you are not getting anything from the device.

How much standby really costs

The best-known measurement study comes from Lawrence Berkeley National Laboratory. In 2000, researchers measured whole-house standby in ten California homes and found between 14 and 169 W per home, averaging 67 W, which made up 5–26% of each home's annual electricity (LBNL). TVs, set-top boxes and printers had the largest standby losses. The same work estimated that replacing those devices with units drawing 1 W or less would cut standby losses by 68%. LBNL's Alan Meier later gave a "best guess" that standby accounts for 5–10% of an average US home's electricity.

Those homes are now 25 years old and American, and devices have improved a lot, largely because of regulation. Many modern products draw around 1 W or less in standby. But homes also have far more connected devices than in 2000.

For the UK, the Energy Saving Trust estimates that an average household in Great Britain could save around £45 a year by remembering to turn appliances off standby (Energy Saving Trust). Treat that as a rough average; your figure could be much lower or higher.

The arithmetic

A device drawing power all the time runs for 8,760 hours a year (24 × 365). So:

The UK rate is the Ofgem price cap average for October to December 2026 (Direct Debit, England, Scotland and Wales). The EU figure is the first-half 2026 household average reported by the Brussels Times from Eurostat data. Use your own unit rate for your own sums.

What EU rules now allow

The EU has regulated standby for years. The current rules are in Ecodesign Regulation (EU) 2023/826, which replaced the older 1275/2008 regulation and has applied to new products placed on the market since 9 May 2025. In broad terms:

• Off mode and simple standby are capped at 0.50 W, with the off-mode limit tightening to 0.30 W from May 2027.
• Standby with a display (such as a clock) is capped at 0.80 W.
• Networked standby is allowed more: around 2 W for most networked products, and up to 8 W for devices that need to stay highly available on a network, such as routers (with a further reduction planned for 2027).

The safest summary: the EU now caps standby for most new products at around half a watt. The European Commission expects the revised rules to save about 4 TWh of electricity a year by 2030, worth around €530 million a year (European Commission).

This is good news, but it only covers new products. That ten-year-old amplifier, the old set-top box or a cheap charger from outside the EU may be far above these limits.

Which devices tend to waste the most

How to measure your own standby

1. Read your background load. Late at night, with everything that normally stays on still on, check the live power on your smart meter display. That is your home's minimum, including fridges and routers.
2. Measure device groups. Put a plug-in energy meter or a smart plug that monitors energy on your TV and entertainment extension lead, then switch everything to standby. Note the watts.
3. Repeat for the office desk, the kitchen counter and the bedroom.
4. Multiply by 8.76 to get kWh a year per watt, then by your unit rate.
5. Rank the groups and deal with the biggest first.

Our guide to measuring appliance energy use explains each method in more detail.

How to cut standby safely

1. Change settings first. Many consoles, TVs and computers have an energy-saving standby option instead of "instant on". This costs nothing and keeps the device working normally.
2. Switch off at the wall for groups. A switched extension lead or a smart plug on a TV or desk setup cuts several devices at once.
3. Schedule the off hours. If nobody uses the home office after 7 pm or overnight, a schedule removes the need to remember. See our smart plug ideas for practical examples.
4. Keep essentials powered. Never cut power to fridges, freezers, heating and hot-water controls, smoke or security alarms, medical equipment, or anything the manufacturer says must stay on.
5. Replace the real offenders. If an old amplifier or set-top box draws 10–20 W doing nothing, a newer model that meets the current EU limits may be the better long-term fix.

Common mistakes

• Unplugging everything in sight. Chargers and modern devices on half a watt are not worth the hassle. Measure first.
• Using a device that wastes more than it saves. Any smart plug or "standby saver" uses a little power itself. Putting one on a device that draws 0.5 W in standby can cost more than it saves.
• Cutting power to things that need it. Some boilers, recorders and network devices misbehave or lose settings if switched off at the wrong time.
• Forgetting idle isn't standby. A desktop PC left "on but idle" all night can draw many times more than any standby figure.

Where Wattly fits (and where it doesn't)

A Wattly smart plug is useful for finding and cutting standby on a group of devices. It shows live watts in the Tuya Smart app, so you can see exactly what your TV corner or desk draws when nothing is in use, and then set a schedule or switch it off remotely. Schedules are stored on the plug, so they keep running even if your internet drops.

The Wattly plug itself uses under 1 W in standby. That means it is worth it on a cluster of devices drawing several watts, but not on a single modern device already drawing half a watt. And it cannot help with hard-wired loads or tell you your whole-home background draw; for that, use your meter or smart meter display.

Related reading

• What uses the most electricity at home
• Do smart plugs save money?
• Smart plug energy monitoring explained
• Wi-Fi vs Zigbee smart plugs