I’ll just come out and say it: 50W. I know, I know an order of magnitude above what’s actually needed to host websites, media center and image gallery.
But it is a computer I had on-hand and which would be turned on a quarter of the day anyway. And these 50W also warm my home, although this is less efficient than the heat pump, of course.
What’s your usage? What do you host?
What are your electricity prices that 30w costs €5/m
Spain would probably be around that much if my calculations are correct.
30w x 24 hr./day *30 days/mo. = 21.6 kWh. I pay about $.25/kWh, so $5.40.