Option 2: Polyiso Foam Board Insulation
If you plan on traveling to primarily warm places, thick insulation like wool will not be as necessary for your van conversion. However, keep in mind that less insulation will also make the outdoors a bit noisier.
Polyiso foam insulation is made from foam plastics and is a very popular choice among van dwellers. It has a high R-value for its size, making it a great option for camper vans. However, rigid foam does have a couple downsides: it’s less environmentally friendly, and it has the potential for moisture build-up if left exposed to inclement weather during the conversion process.
Because rigid foam is difficult to bend and curve to fit certain areas, don’t be afraid to use a bit of wool insulation in those areas.