Infoworld has an article debunking some PC power myths.
The article claims that the average PC uses 89 watts per hour. Divide 89 by 1000 to get the number of kilowatts. If the PC were left on for 24 hours it would consume about 2.1 kilowatts. For my power plan it costs about 5 cents per kw off peak and 17 cents per kw on peak. On peak is 8 hours in the day. So the total cost per day is about 21 cents. At that rate the cost per month is about $6.30.
In my case electricity is so cheap that there’s little financial incentive to turn my computer off when not in use. And since it’s a server, that’s not really an option anyway. You should do your own calculations to see what it costs to have your PC on 24 hours a day. If your computer isn’t being used 24 hours a day then it shouldn’t be on 24 hours a day anyway. Turn it on when you get home from work or school and turn it off when you go to bed.
Monitors, printers, scanners, etc are what start to add to that bill. Screen savers prevent burn in. They don’t save electricity. As such you should have your monitor go into power saving mode automatically when not in use. I have my screen saver set so that it goes on after 10 minutes of inactivity and after about 20 minutes the monitors go into power saving mode.
The reason screen savers can actually cost you more money is because some of them require your graphics card to do some work which requires more power. The best screen saver is just a blank black screen or a simple static image moving around.
The biggest obstacle to powering off a computer is the boot up time. I have a dual core 2.4ghz system that runs Windows XP Pro and boots in under 30 seconds. If your computer takes a very long time to boot you may want to review the software that is installed on your system and remove some of it.
