As Verdiem CEO Kevin Klustner told me in my latest CBS News Tech Report podcast, two-thirds of the energy they consume costing nearly $6 billion a year and putting about 300 tons of carbon dioxide into the atmosphere.
Much of that energy could be saved if PCs would enter into a "sleep" or suspend mode when not in use. Configuring a machine to do that is pretty easy but many people don't bother. Windows Vista and Macintosh come pre-configured to go into sleep mode after a certain period of time but XP machines are often set to remain at full throttle unless the user turns them off or manually enters sleep mode. You can check the settings on your machine by clicking Power Options from the Control Panel.
One problem with both XP and Vista (and sometimes Macs) is that they occasionally fail to go into suspend mode or do go to sleep but don't wake up, requiring you to re-start the machine. Fixing this problem can be vexing because it can be a result of numerous issues including drivers for devices on your machine or programs that keep the machine awake so that they can perform a background task. Even experts such as myself can have a tough time getting their PCs to go to sleep and wake up as needed.
For XP and Vista there is a convenient free program that can help you set sleep and suspend modes and, in some cases, work where built-in Windows suspend controls fail to function properly. It's called CO2Saver and you can get it from http://co2saver.snap.com/. It takes seconds, works automatically and is easier to configure than Windows own energy management software.
Of course PCs aren't the only devices to rob power from your home. Personal video recorders such as Tivos and devices you get from cable and satellite companies are even worse because they are designed to keep their hard disks spinning 24 hours a day consuming as much as 47 watts of power 24/7.
Frankly, I think there is a lot more that electronics companies can do to make their products green. In the mean time, there are things we can do as well. If you haven't done it yet, make sure your PC is getting a good night's sleep and taking naps when you're not using it.
For a more exensive discussion of this topic, check out my New York Times column from last year, Putting Energy Hogs in the Home on a Strict Low-Power Diet