What about the storage devices (the S in NAS)? My external HDD (just for reference) has an AC adaptor that outputs 12V at 1.5A, so that's another 18W. And most people who care enough about storage to have a NAS have multiple disks...
I'm not saying it isn't under 40W - as you note, if it's idling properly, it's pretty easy to have a NAS including disks under 10W idle. But the electricity cost is not negligible when you are running something 24/7. Even 10W24hr30day is 7.2kWh per month, and most places cant count on 8c/kWh electricity anymore.
> My RPi 4b runs on a 18W power supply, which would put it at 432Wh per day
Which would be 13 kWh per month. If we're comparing to monthly fees for cloud storage, it's important to look at the same time frame.
I have two SSDs on it that are powered by the RPi itself, so the whole package is < 18W. Also, SSDs use way less power than HDDs.
> Which would be 13 kWh per month. If we're comparing to monthly fees for cloud storage, it's important to look at the same time frame.
Yes, running at max load. A more realistic load will be 3W/hr -> 72W/day -> 2kWh/month. That would put it at ~0.3€/month at a realistic load and ~1€/month at max load (0.15€/kWh where I live).
You also have to take into account there's other stuff running on such "NASes", like the PiHole, a git server, a plex server, which are going to cost you separately if you need them. On the other hand, my setup cost me ~300€ (RPi, charger, drives, USB-SATA adapters), which buys a whole lot of VPS and a whole lot of online storage.
Yes, SSDs would certainly help cut your power load down significantly! My system has 3 HDDs and it's a fairly small NAS compared to many - SSDs are prohibitively expensive once your storage needs get above a couple TBs.
I'm not saying it isn't under 40W - as you note, if it's idling properly, it's pretty easy to have a NAS including disks under 10W idle. But the electricity cost is not negligible when you are running something 24/7. Even 10W24hr30day is 7.2kWh per month, and most places cant count on 8c/kWh electricity anymore.
> My RPi 4b runs on a 18W power supply, which would put it at 432Wh per day
Which would be 13 kWh per month. If we're comparing to monthly fees for cloud storage, it's important to look at the same time frame.