Hi friends. I'm a newbie in self-hosting, though I've been managing (virtual) linux servers at work for a couple of years. I'm completely ignorant on the hardware choices out there, hopefully you can point me to the right direction.
Here are my requisites:
Low power consumption, I plan to have it connected 24/7 and I'm kinda concerned on how much it will impact the electricity bill
Ethernet port, preferably gigabit but whatever
Graphical performance is not important as I don't plan to connect it to any display. As long as I can ssh into it, I'm good.
Services I plan on installing, for starters:
casaOS
pi-hole, or equivalent
Home Assistant
Kitchen Owl (nice to have)
Paperless-ngx (nice to have)
I live in europe and my budget is around 80 euros or so. Thanks in advance!
Risking sounding like a broken record, I always suggest Tiny/Mini/Micro 1L form factor office PCs. Lenovo, Dell, and HP all create ultra small office PCs that make great low power servers. A Pi will use 5-9w at idle, while these PCs will use 11-13w idle. They also use more standard components such as NVME drives, 2.5" drives, and replaceable RAM. Easy to find under $100 USD used, I'm sure you can find them under 100 euro.
SFF = Small Form Factor. It's smaller than traditional ATX computers but can still take the same RAM, processors and disks. Motherboards and power supplies tend to be nonstandard however. Idle power consumptions are usually very good.
USFF = Ultra Small Form Factor. Typically a laptop chipset + CPU in a small box with an external power supply. Somewhat comparable with SBCs like Raspberry Pis. Very good idle power consumption, but less powerful than SFF (and/or louder due to smaller cooler) and often don't have space for standard disks.
The Pi Zero is 2w max... It's downside is it draws 2w MAX. Power is power, only so much you can do in 2w. As you pointed out, the 4 and 5 can do more, because they can draw more, (or they draw more so can do more, it's all related).
The key seems to be ability to minimize the idle power while still capable of ramping up to something useful when you need it - like the micros you've listed.