I've got about 50% of the Sprinter insulated with this stuff and have realized I have way more than enough to do the Eurovan too. So I cracked it open to do some panels.
My hope is that it will knock down some road noise and retain heat/cold better, which means the heat & AC don't have to be run as hard, which will all make conversation and the radio better. Plus more comfortable camping.
This stuff is very similar to the factory stuff that is behind every panel on the van already. Just thicker and a touch more dense. It should still breath well so that it dries vs trapping moisture. (Shouldn't be an issue here in the high desert anyway). One of the boxes was wet when I got it from sitting in the rain and the insulation was dry to the touch. It wasn't absorbing the moisture anyway.
Here is a picture of the inside of the rear hatch panel as an example.
Note the giant open empty spaces!
Rear hatch stuffed with sound insulation. Amazing the thud the panels make when filled with this stuff. Seems to work very well.
So far all I've done is the slider and rear hatch and there is a notable difference in noise and temperature.