Insulate supply duct
I put the "bubble wrap" insulation on a section of round duct. See attached picture. The instructions said to spiral it onto the duct, but I put it in 16" sections with no overlap, just because I think it looks better this way. Secured with aluminum duct tape. There is an axial seam on the "bubble wrap", but I rotated the wrap so that it is not visible. It was fast to put up, and looks decent. If you are looking for higher R value, google "Mcmaster Carr Supply" and then do a search for "duct insulation". Advance through the pages, because they will have several pages of insulation literature.