Tinker with your computer’s energy settings.

Almost all modern computers (Windows XP and Vista and Mac OS X) have a control panel that allows you to set various energy saving options, such as how long before the computer and the display go to sleep during inactivity. Play with these settings and try to find the lowest numbers that are still convenient for your use.

For example, I set all of my settings to an hour (lower than what the defaults were) and found they didn’t bother me at all. So I kept lowering them. Now, my screen saver pops on after three minutes and everything else goes to sleep after five – I’ve found that if I’m away longer than that, I’m usually away for quite a while. A wiggle of the mouse wakes it up, so it’s no big deal.

This can save a ton of energy over the long haul. Let’s say the energy use of my system drops 60 watts when it goes into sleep mode. If these settings cause it to spend two more hours a day in sleep mode, that’s 43.8 kilowatt hours, an automatic savings of $4.38 in a year.