Option 2: Foam Board Insulation
If you plan on traveling to primarily warm places, thick insulation like wool will not be as necessary. However, keep in mind that less insulation will also make the outdoors a bit noisier.
Rigid foam insulation is made from foam plastics and very popular choice among van dwellers. It has a high R-value for its size, making it a great option for vans. However, rigid foam does have a couple downsides: it’s less environmentally friendly, and it has the potential for moisture build-up. So be sure not to leave it exposed to the inclement weather during the conversion process.
Becuase 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.