Did an idle power test with a kill-a-watt.
I swapped out the hdd for a 2.5" SSD
Idle with Ubuntu is 8-10 watts dipping as low as 7 watts on occasion.
Might be able to get even lower if you were to remove wifi and the disk drive, probably not much if any though. Also a m.2 drive might be less, but probably not even detectable.
Still very impressive.
I will be ordering 1-2 more for PFsense, and might even go the DAS route and replace my Unraid server. It gets very little use as is and the power savings would be worth it. Or at least build a backup box.