This. :thumbsup:Many factors to be considered, and more info needed. What is finished floor material would be the main one, is finished floor height to be a factor, size of area to be heated? I normally use 120 electric, set in self leveling compound in bath floors, never an issue.
I think you mean 210.11(3)Exc. I suppose so, if the heat and other connected loads are under 10A (210.23(A)(2)). In practice, I've always mentally excluded heating loads from those circuits, but I can see it's not an absolute rule.Yes. NEC 201.11(3)Exc.