But how much are you paying in electricity costs to run your PC at home? I keep my linux server, router, modem, and obi100 powered up 24/7, and calculate that it costs nearly $8/mo. in electricity, and the combined average load of all of that is ~90W. I imagine a sizable amount of that is from the server and HDD's, but being able to lower the power consumption could potentially save a couple bucks a month in power usage.
