Save £100 by greening your PC's power bill

2. Schedule your router to power down
Money saved: £3.11 a year

Some internet routers allow you to schedule automatic power downs when you don't really need a web connection -- 11pm to 7am, say. Look in the web page settings of your router to set it up. If you can't see an option, make sure you've downloaded the latest firmware from the router maker's website.

Still can't see the option? A lo-tech way to do this is buy a single plug timer -- the sort you'd use to set lamps on timers when you're away on holiday. Just connect one to your router's plug and set the router to power down during the hours you're usually snoring.

Both methods have one big advantage over just unplugging at the wall: once you've set it up, it requires zero conscious effort on your behalf.

You're also likely to save more than £3 a year. My saving is based on turning off a mega efficient router such as the new D-Link DIR-855 for eight hours each day. If you're using something more complex -- such as an Apple Time Capsule -- you'll be looking at double digit savings on electricity by turning off.

There's another bonus too: no internet means no hackers while you're snoozing.