The best way to insulate your van is to use Havelock Wool 48"x16"x2" batts. I bought two boxes which cover 100 ft.² each to insulate my Chevy express van which had previously been my work van. I've been a builder since the early 70s and I think this is the first time I can truly say that I enjoyed installing insulation. The stuff looks like a fiberglass, but it smells like lanolin and it's so soft. You could cuddle up to it. The Havelock Wool people explain on their site that you don't need a vapor barrier if you use this type of insulation. I just talked to a sales rep to get an idea of what I should sell this for. The same box sells for $175 and with tax and shipping to our area. The price would come to at least $225.