We have a bathroom in a finished basement. While removing the old bathroom fan I discovered that the duct pipe leading outside is not insulated.
Should the bathroom fan duct be insulated traveling inside the joist space? What are the risks if it is not?
From what I have researched, bathroom fan ducts should be insulated when "traveling through an un-conditioned space", like an attic. Does the space between the joists in the basement count as un-conditioned?
- The duct runs about 20 feet to the side of the house
- There is a strange vertical "S"-shaped bend in the middle.
- The run appears to be roughly 10 feet on each side, with the S in the middle.
The duct also sits right next to a hot air vent. Is this all the more reason to insulate it? Is there a risk that the hot air duct gets hot enough to melt e.g. a vinyl wrapping around the insulation sleeve?
If I insulate both ends, am I just creating more problems for myself by making the condensation form in the middle of the "S", where I can't reach it? Would it be better to leave the entire thing, and have the condensation happening at the fan?