The best insulation I have ever found is a product that's been discontinued,
called Enguard. It is made of microfibers spun from pre- and post-consumer
waste plastic bottles. Hydrophobic, vermin proof, light weight, no flyaway, no
sag ever, totally safe. I bought out the remaining stock of it a few years ago
and still have about 6-8 bags remaining. Each bag contains five 2' x 8' R19
(5" thick) batts, more than enough to do one van. Easy to split off for
thinner cavities. I'd love to sell off some of it but the problem is it's in
central Oregon...maybe I should send a pallet to the east coast.
https://westyventures.com/enguard%20(1).JPG
Karl