On Feb 27, 1:39*pm, wrote:

return "ducts" are sometimes formed by the space between the 2x4's and
sheetrock, no actual ducting is used...


I wish that were the case here. It's just an empty cavity bordered by
the top plate, the bottom plate, and two studs. Stuck my head in and
looked. And, yes, the HVAC performance on that floor is not very
good.