Depends on the CPU, but should be fairly low. I found this article discussing similar mini PC models and comparing power usage:
https://www.techaddressed.com/reviews/i3-desktop-homelab-solutions/#power-use
ServeTheHome has an article about the newer G4 model with some power numbers:
https://www.servethehome.com/hp-prodesk-400-g4-mini-project-tinyminimicro-guide/3/
Depends on the CPU, but should be fairly low. I found this article discussing similar mini PC models and comparing power usage:
https://www.techaddressed.com/reviews/i3-desktop-homelab-solutions/#power-use
ServeTheHome has an article about the newer G4 model with some power numbers:
https://www.servethehome.com/hp-prodesk-400-g4-mini-project-tinyminimicro-guide/3/