i am looking for put new heat insulation for cargo van but i dont know which one will work better?

I have used Owens-Corning Pink Panther for 37 years and 1/4 inch plywood. I leave an inch by the floor and an inch at te top of the sides to breathe. The top I split the 3 1/2 insulation so not to cram it full but still use a good sense about it. I always have good luck and good insulating results. I did have my favorite van ...75 dodge with spray foam insulation installed. the acid in the foam ate the van out from the inside out. By the time I saw rust on the outside ...It was too late. IOt however let me sleep till noon in 100 degree heat... like sleeping in a Styrofoam cooler, but not worth sacrificing your van for a couple years , then trashing it out at a salvage yard. I went back to the basics with the phoenix and am very happy with what I have. For the money opposed to the other stuff Aluminum coated blankets and all the other High tech stuff out there, this to me is the best way to go to me. Cheap and effective. just let it breathe, give it air so not to create condensation, as with anything. Think before you build.

i just installed "Reflexit" with aluminum tape which i got at Home Depot.

When I did my 82 I used sheets of styrofoam just placed between all the ribs in the van and 1/4 inch plywood. It leaves a breathing space and does not absorb if any condensaion. Worked very well

Umm what about Ez Cool? does it work good?