I see there are some discussions for how to orientate the older external Zwave stick hubs, but I'm not seeing anything about the C5 (or C7) with internal Zwave radios.
Does it matter? I'm about to move my hub to the center of my house (from a corner), and want to do it right. I'm talking ceiling or wall. =)
I had no issue mounting my hubs vertically (both used to be on walls with a 3D printed mount), on their side (in a 3D printed mount, my primary hub is this way) or just sitting as they might normally (my backup hub is that way right now).
The only reason they are not still on walls is because the room I used to use as my hobby room/office got changed so I came up with different locations for now.