This is something that we spent a lot of time researching on our first build. After a lot of reading, question asking and Youtube watching, we ended up settling on wool insulation. We chose wool because of its excellent insulating and sound-dampening properties, and its ability to handle moisture well. One of the other eco-friendly options that we’ve seen people use in vans is denim/ recycled cotton, and although it’s a reclaimed material, we were concerned about moisture and issues with settling.
The wool was pretty darn easy to install and remarkably adaptable to a Sprinter’s many contours, nooks, and crannies. This time around, we were excited to discover a US manufacturer of wool batts. We’ll be using Havelock wool (based in Reno, NV) for our second conversion. Havelock’s website has the best summary we’ve seen of all the advantages of wool insulation. They also have a great vanlife-specific page, where they address the differences in insulation options, and quantities of wool needed to insulate various types of vans. The guys at Havelock have been incredibly helpful so far (they have their own Sprinter, so they ‘get it’– and have experience insulating a van), and we’re really excited to see how their insulation compares to the wool batts we used last time.