Who needs insulation? its a load of rubbish created by most campervan converters to get more money out of you......this is just my opiniun. One other thing regarding insulation. Not that many years ago converters didnt insulate vans and they are still running around today with happy owners. I have spoken to many of them and they dont have a problem without insulation in the vans.
Everyone I have spoken to wouldn't dream of not insulating their vans.I didn't trust any conversion company to do mine,I did it all myself.
The difference is a bit like chalk and cheese.
Definitely not an area to scrimp and save on,especially as most will have spent a good 30 grand on their van to start with.