Its fascinating that electricity is really the biggest cost of computing. I put a server in my house which was supposed to save money, but actually the electricity cost was something I hadn't thought of and really adds up. esp when the AC has to run to remove the extra heat. So much old hardware out there but its going to get junked as new hw is more efficient.
This is why for my home server I didn't get second hand servers but built the following in a 2U case that fits in my network closet: Asrock Rack c246 WSI (Mini ITX workstation board) 32GB DDR4 ECC Udimms (16GB x2) Core i3 9100T (25w, low power 4 core part, supports ECC, and quicksync) 6 IronWolf 4TB NAS drives The 6 drives are in RaidZ2 so give 16TB usable space, and at full pelt the max power consumption is 60W for…
Servers are more efficient than people give them credit for. It's close to a gaming PC in electricity usage. Certainly not 60W (or what people can get with NUCs and RPi clusters) but for the power I get, it's very much worth it.