TV sets, stereos, VCRs and the like have long relied on standby power. More recently, "convenience" electronics have been grafted into up-market household items such as dishwashers, coffee makers, cordless telephones and washing machines, all of which are designed to be permanently powered.

Don’t think that these devices use much power when "off"? Well, you might be surprised to discover that 10-15% of all household power is consumed by devices in "standby" mode. According to a 2001 study by "Choice" magazine, appliances not performing their main task drew a constant total of 87W, on average.

That works out to 760kWh in a year, for a cost of almost $100. And standby power consumption certainly hasn’t decreased since then.

Consider the 100 million homes in the United States, for example. In total, they consume roughly 5GW of standby power. According to one source, this equates to about 8GW after distribution losses and generation reserves, or about the output of eight power plants. And that’s just for the domestic sector!

With this in mind, you may wish to save some money and the environment by switching off appliances at the power point when not in use. Of course, it’s simply not practical to power off all devices. For example, microwave ovens and VCRs include a real-time clock that would need to be programmed at every power up, while cordless phones need to be on all the time. However, other devices such as PCs and their peripherals can be switched off.