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?
I recommend buying one of these things for finding this out: https://ae01.alicdn.com/kf/HTB1sJx0lrZnBKNjSZFGq6zt3FXao/EU-Plug-Digital-Voltage-Wattmeter-Power-Meter-Consumption-Watt-Energy-KWh-Socket-220V-230V-AC-Electricity.jpg