The Cost of Leaving Your PC on 24/7
Between my server and my Windows Media Center home theater PC, I have at least two PCs on all the time at home. Have you ever wondered how much it's costing you to leave a computer on 24 hours a day, 7 days a week?
The first thing you need to know is how much power your computer draws. The best way is to measure the actual power consumption. You'll need a $30 device like the Kill-a-Watt or Seasonic PowerAngel to do this accurately.
Once you get one, you'll inevitably go through a phase where you run around your home, measuring the power draw of everything you can plug into a wall socket. For example, I learned this weekend that our 42" plasma television draws between 90 watts (totally black screen) and 270 watts (totally white screen).
Based on a little ad-hoc channel surfing with an eye on the Kill-a-Watt's LCD display, the average appears to be around 150 watts for a typical television show or movie.