Save £100 by greening your PC's power bill

3. Use a shortcut for standby
Money saved: £20 a year

Let's say there are two hours everyday -- meetings, calls of nature, coffee top-ups -- when your computer could be running in standby. Take that same Dell 9200 desktop we looked at earlier. Since it only uses 1.8 watts in standby mode, putting it into standby for two hours a day could save you £20.

If you're running Mac OS X or Windows, the quickest way to power down into standby is to press your machine's power button. One light touch of a Mac's power button will put it to standby ('sleep' in Mac speak). In Windows, you can configure your power button to work as a standby button in 'power options' in the Control Panel.

Of course, the power button may not always be easy to reach, and you might hate navigating through menus to activate standby. Which is where keyboard and mouse button shortcuts come in. On Windows, installing free software such as Slawdog Smart Shutdown offers a one click button to put your machine into standby. On a Mac, the keyboard shortcut of option-command-eject will put your machine to sleep.

Or you could even buy an EcoButton, a USB gadget that activates standby with one button press.