Instant expert

Standby power

Appliances can act as energy vampires, secretly sucking up power ... and money.

power button

Credit: iStockphoto

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What is standby power?

Also known as 'phantom power' or 'idle current', standby power refers to the "invisible" energy used by an electronic appliance while plugged in but not in operation.

A large number of household appliances have a standby mode - televisions, stereos and DVD players are just some of the usual suspects.

In the standby mode, these devices continue to pull a current even when they are supposedly 'turned off'.

Just look at the little red light on your television telling you that it is ready when you are and you'll quickly realise that your TV is still using electricity.

Ok, but what's the problem?

On a day-to-day basis the standby power of an electronic device might not amount to much. However, the large number of appliances that operate on standby mode and the fact that many of the devices are on all day every day, means that the net result is a large amount of power use.

In fact, it's been estimated that standby power accounts for around 10 per cent of household energy consumption and costs Australians more than $950 million a year. This equates to more than 6.5 million tonnes of carbon dioxide emissions.

That's a lot of CO2 - can devices really emit that much power when on standby?

Yes! There are three types of standby power, each consuming different amounts of energy depending on the appliance.

Active standby mode is when an appliance is turned on and ready for use but is not actually being used, for example a stereo that has finished playing a CD. According to a 2006 report on Standby Power, stereo systems consume around 20 watts like this.

Passive standby mode is when an appliance such as your television is turned off but is ready to be switched on (often with a remote control) or it is performing some secondary function, for example a microwave with a digital clock.

Studies suggest that microwave ovens consume between 1W and 4W in passive standby mode.

Off mode standby power is when a device is connected to the mains electricity but is switched off by a switch or button (and can't be 'woken' by a remote control); computer speakers for example consume around 2W in this mode.

What can I do about it?

Put simply, if you're not using an electronic device then you should unplug it or turn it off at the wall. When shopping for new appliances, consider buying energy saving ones - Fujitsu Siemens Computers has developed a "zero-watt monitor", the world's first computer monitor that requires no electricity at all when in standby mode for example - or devices that offer a real 'off' switch.

Another option is to plug everything into a power strip and simply use the switch to turn it off rather than unplugging and plugging things in.

'Smart' power strips such as the aptly named "Smart Strip" can detect when computers or other devices are on or off and shuts off the power accordingly, thereby eliminating the idle current being drawn from the appliance.