I am installing ceiling fans in the bedrooms, which have no ceiling fixtures at all. I thought I would simply tap the entry switch for the switched outlets in the bedrooms, but the switches get a spur line only. I think all the outlets are already too packed to tap one of them. They all have a switched and an unswitched receptacle, so get a lot of connections. All other circuits up there look well loaded already. I plan to pull new wire. I usually pull 12 guage to minimize resistive losses. I see no easy place to pull it from basement to attic. This is a 2 floor house with basement and attic. For some reason, the previous owner pulled new heat pump tubing to the attic from the basement, and left the old, which happens to be on an outside wall, whereas the new tubing is on an interior wall. (I have not asked them, but why would one do this? It is cut off at the entry into the attic, and into the basement.) The holes in the basement subflooring at the new tubing are huge (2"), and would accommodate wire, and I could probably dangle a chain all the way down. The old heat pump tubing is still there, in that exterior wall, too. The insulated tubing is too small (1/4"), but the uninsulated tubing appears to be 1/2". It looks like it could serve as a conduit to the attic. If outside buried conduit can be metal, can this copper tubing be code-approved conduit inside the house? I imagine I should not pull wire up beside the new heat pump tubing, but let me know if that defies national code.