Standby Power Calculator
Some of your electricity bill pays for devices doing nothing. A router, a TV box, a console in rest mode — each draws a small amount continuously, and continuously adds up.
Set the number of each device you have and add your unit rate to see what that costs over a year.
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145 kWh per year
16.5 W drawn continuously. Add your unit rate above to see the cost.
What standby power is
Standby power — sometimes called phantom load or vampire draw — is electricity used by a device that is switched off or idle but still connected. It keeps a remote sensor listening, a clock running, a network connection alive or a device ready to wake quickly.
It is different from the running cost of an appliance you are actually using. If you want to know what one wash cycle or one hour of television costs, the appliance electricity cost calculator is the tool for that. This page answers a different question: what are you paying for things you are not using?
What actually costs you money
The reputation of standby power does not match where the cost actually sits. Phone chargers left plugged in are the classic example given, and they are close to irrelevant — a fraction of a watt each.
The real load is in devices designed to stay connected: broadband routers, TV and set-top boxes, and games consoles in rest mode, each around 8 to 10 watts. Those run every hour of every day, which is what turns a small number into a noticeable one.
Modern televisions are a genuine success story here. Regulations have pushed television standby to well under a watt, so a TV on standby now costs a fraction of what the set-top box beside it does.
What is worth switching off
Not all standby is waste. A router that is switched off has no internet. A set-top box that is off cannot record. A freezer is not on standby at all. The saving only counts if the device was not doing anything you wanted.
Worth targeting:
- Games consoles, if you do not need remote downloads overnight.
- Set-top boxes for services you no longer watch.
- Printers, desktop computers and monitors overnight.
- Second televisions and sound systems in rooms rarely used.
Usually not worth it:
- Broadband routers, unless you are away for days.
- Anything with a clock you rely on.
- Phone chargers, where the saving is a few pence a year.
Measuring it yourself
The wattages in the calculator are typical published figures. Your own devices will differ by make, age and settings — an older console can draw several times what a current one does in the same mode.
A plug-in energy monitor costs very little and gives the real number for a specific device. If you have a smart meter, watching your overnight baseline when the house is asleep is a decent proxy for your whole-home standing load.
For what that consumption looks like across the country, the typical energy use page carries the published UK figures.
Frequently asked questions
How much does standby power cost a UK household?
It depends entirely on which devices you have. A household with a router, a TV box and a television on standby draws around 16 watts continuously, which is roughly 145 kWh a year. At a unit rate of 26p that is about £38. Households with several consoles, set-top boxes and desktop computers can pay considerably more.
Which devices use the most on standby?
Broadband routers, TV and set-top boxes and games consoles in rest mode are usually the largest, at roughly 8 to 10 watts each. Modern televisions are far lower at well under a watt. Phone chargers left plugged in without a phone attached draw very little indeed, despite their reputation.
Is it worth switching things off at the wall?
For a games console in rest mode or a rarely used set-top box, yes. For a router, no: switching it off means no internet, and a device that is off cannot do the job you bought it for. The saving is real but modest, so it is worth targeting the few large always-on loads rather than unplugging everything.
Do smart plugs use power themselves?
Yes, typically around half a watt to a watt each. A smart plug used to switch off a 10 watt standby load still saves most of it, but fitting smart plugs to very low draw devices can cost more power than it saves.
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Written by
Rob Gibbs
Hi, I'm Rob, and I run Energy-Review.co.uk. I initially started this project in 2018 when I was looking to switch energy suppliers and found there wasn't a website that provided simple, data-backed reviews on all the suppliers available. Since then, I have spent a lot of time (too much, some may say!) looking at all publicly available data about each supplier and writing reviews using this information. These reviews are updated as regularly as possible, and any data is backed up by a source where necessary. I have also started writing guides on various energy-related topics, which hopefully you will find useful. If you find any issues, please use our contact form to let us know.