Buy a power meter from maplins for £10 and use it to find out. You can use it for other things around the house too. You'll be horrified how much some things use in standby
You'll also be quite surprised over how little your PC uses compared to what you think it uses.
(Also, computer power supplies are often up to 95% efficient, but only at close to the rated load, in case anyone thinks otherwise when looking at the label on their PSU.)
Once you have the figure, go to
http://www.abyssunderground.co.uk/ca...nningcosts.php
Enter the watts, pence per kWh, hours, and hit submit.
EG for me, its 120 watts @ 14p/kWh for 24h/day:
£0.46 per 24 hours
£3.23 per week for 24 hours a day
£12.9 per month (28 days) for 24 hours a day
£38.71 per quarter (3 months) for 24 hours a day
£167.73 per year for 24 hours a day
Also if you're running it headless, you won't need a powerful graphics card. Use the on-board if you have any. Sound isn't needed so remove sound cards if it has one. Also tell the HD's to turn off after 10-15 mins of inactivity to further reduce usage when its not in use.
I specifically designed my server to be very power efficient, unfortunately the hard drives made it somewhat infficient... 64watts inc 1 HD, shoots up to 120watts with 4 + 2 external. The externals turned off reduces it to 104watts, so the 1tb drives I have are quite hungry. Still, mine turn off overnight (I think) so it should reduce it. I need some logging equipment!
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