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?
5W vs 50W is an annual difference of 400 kWh. Or 150 kG CO2e, if that’s your metric. Either way, it’s not a huge cost for most people capable of running a 24/7 home lab.
If you start thinking about the costs - either cash or ghg - of creating an RPi or other dedicated low power server; the energy to run HDDs, at 5-10W each, or other accessories, well, the picture gets pretty complicated. Power is one aspect, and it’s really easy to measure objectively, but that also makes it easy to fetishize.
At $0.13/kwh 100 watts 24/7/365 will cost you $113.88 a year, or roughly $10 a month. Little things add up.
$10/month is one drink in the pub on one Friday night out of four. It’s not even a movie ticket.
European electricity rates are closer to $0.30, and I agree that 100W 24/7 is a cost worth being aware of. I think we’re seeing in this thread that it’s pretty easy to find a system with standard PC parts from the past decade that idles in the 50W range, like OP, even with a couple of HDDs, and $50/year (US), even $150/year (EU), electricity cost to keep an old desktop out of a landfill maybe doesn’t seem so bad.
I mean, one should think hard whether their home lab really needs a second full system running for failover, or whether they really need a separate desktop-based system just for NAS. And maybe don’t convert your old gaming rig and its GPU to a home server. Or the quad-Xeon server that work is ‘just giving away,’ even if it would be cool to have a $50,000 computer running in the basement.