It is of course possible to convert a van into a motorhome without installing any insulation, though it would not be particularly advisable. Good insulation will help to maintain an ambient temperature inside the van when the temperature outside the van is either too hot or too cold for comfort. It should also help to reduce condensation inside the van and to a lesser extent, offer some sound insulation if needed. It’s a topic that is often discussed on the SBMCC forum with regular postings of questions, answers, problems and solutions regarding the insulation of a conversion.
There are of course several types of insulation that can and have been used in van conversions. The choice you make can be governed by many factors, including cost, ease of fitting, type of van and use to which the van will be put once converted.
There are blanket type rolls of insulation such as Rockwool, Glass fibre roll, or sealed space blankets, others may come in the form of firm sheets that can be cut to size and fixed in place and these can include sheep wool, Rockwool ‘batts’ or polystyrene type products such as Celotex, Kingspan and Xtratherm.
Other types of insulation require being ‘sprayed’ onto the van walls whilst there are even flexible closed cell mats which can be glued to the walls.
Many self builders fit a vapour barrier either side of their insulation in order to avoid problems with condensation being absorbed by some types of insulation.
DVLA requirements for a van to be classified as a ‘Motor caravan’