Insulation is by far the most commonly misunderstood aspect of a camper van, skoolie, and recreational vehicle DIY conversion. And for good reason– there is so much misinformation out there! We spent weeks researching radiant barriers, vapor barriers, and dozens of insulation options to find the best non-toxic camper van insulation. We’re sharing the lessons we’ve learned to help you have the best conversion van with natural non-fiberglass insulation. Don’t make the same mistakes we’ve seen hundreds of vanlifers make! Put down that Reflectix and read this post! And be sure to check out the van life YouTube adventures!
Disclaimer: Between the two of us, we have 15 years experience in construction and green building, but we are not engineers or physicists. Although we have strong opinions that are backed by research, we are not saying that our word is the end all be all. We are 100% open to ideas and would love to hear your comments and suggestions, especially if you are an engineer or physicist or work in the insulation industry!
Lesson One: Don’t waste your time on a radiant barrier- They do (almost) nothing!
Radiant barriers are VERY popular in the van build world, so we’ll likely get some backlash on this. Regardless, we’ve done the research and we’re ready to make a bold claim: Everyone you see installing Reflectix on their van walls is doing it wrong!
When we first started googling how to insulate a campervan we saw Reflectix everywhere. Instagram, same thing. Even Sportsmobile (a popular camper van company in the US that mainly converts high-end Mercedes Benz 4×4 Sprinters) has an arctic package that includes Reflectix on the whole interior. In theory, this concept works– just like the reflective visors you put under you windshield, reflective material inside a van can reflect away some of the sun’s heat (or keep heat in the van during the winter). The problem is that everyone we’ve seen is installing Reflectix incorrectly, which renders the product useless.
For a quick science lesson about radiant versus conductive heat, this video (produced by a radiant barrier company) sums it up pretty well:
If you skipped the video, here’s the takeaway: Reflectix does a great job of blocking radiant heat if it’s installed properly. For installation to be correct, there MUST be an air gap of at least 3/4″ between the foil and any other material. If there is no air gap, the foil acts as a heat transfer conductor and will actually work against you!
An “air gap” must literally be a void space for air only – no paneling, no batt insulation, nothing can touch the Reflectix or it will not block radiant heat. So when you see people sticking insulation directly on top of Reflectix, they are wasting time, money, materials, and actually making it easier for conductive heat to pass through into their van.
To properly install a radiant barrier in your van just isn’t feasible– you would need to run furr strips around the entire interior of your van and then ensure no insulation or paneling touches the foil. This would take up a LOT of valuable space in your van.
Are radiant barriers worth it?
Is it worth it? We don’t think so. Radiant barriers aren’t used much anymore in the residential construction industry because they don’t do very much. Independent studies suggest radiant barriers only reduce cooling energy bills by approximately 2 to 10 percent. It’s estimated that the R-value of a radiant barrier is at best R-value 4.2. This small savings isn’t worth it for the amount of space you’d lose in a proper installation.
We’re grateful for other vanlifers out there who are helping to spread the truth about radiant barriers. Don’t waste your time or money!
Lesson Two: Don’t install a vapor barrier in your van
Many vanlifers install vapor barriers in hopes of preventing condensation moisture from getting to the sheet metal of the van. Unfortunately, installing a vapor barrier in your van will actually increase the likelihood of mold and rust. Air exchange between the interior and exterior metal walls is essential to keep moisture and condensation in check. When you add a vapor barrier, you are trapping the moisture you create from breathing inside the van. This moisture has to go somewhere and so it eventually runs down to the floor of your van, where it can eventually cause rust and even mold. Mold is no joke and can have serious negative health consequences, so we recommend foregoing a vapor barrier and using insulation that will allow your van to “breathe.”
Though spray foam insulation kits do a good job of sealing your DIY camper van, you really want your van to breathe, and so this can be overkill and trap moisture in a tiny space.
Lesson Three: Choose moisture-resistant non-toxic camper van insulation
There’s not a lot of indoor air in your van, so it’s important for your air quality to be as healthy as possible. Sorry to be a buzzkill, but most conventional building insulation materials have toxic or potentially-toxic chemicals. Choosing non-toxic camper van insulation was important to us, so we were able to rule out the following types of insulation right away: fiberglass (toxic when inhaled/installed), cellulose (formaldehyde binders & flame retardants), rock wool (formaldehyde binders), foam board (toxic styrene), 3M Thinsulate (contains potentially toxic polypropylene), and spray foam (contains potentially toxic polyurethane and is also both difficult to install & non-removable). For a complete guide to non-toxic sustainable van products, check out this post!
A Note on Toxic Chemicals
We started going down the rabbit hole researching all the potentially toxic chemicals in insulation and other commonly used construction materials. Ultimately, we decided to exclude this information from this post, but if y’all are interested in the dirty details about various construction products (and the reason we’re building sustainably), please comment below and we’ll write a post about it.
We narrowed our search down to three non-toxic insulation options: recycled denim, hemp, and wool. Denim is not moisture resistant (when it gets wet, it stays wet), which can cause mold. Hemp seemed like a good option, but it typically comes in concrete blocks which would be difficult to install in all the tiny cracks and crevices in the van, so we decided on….SHEEP WOOL!
Sheep wool is the BEST non-toxic insulation for your camper van conversion– it’s sustainable, naturally fire-resistant, breathable, doesn’t retain moisture, easy to install, and it’s literally sheep wool, so there are no toxic chemicals. Check out Black Mountain manufacturer information for information about the wool we used.
How to install non-toxic camper van insulation in your camper van: Step-by-step
- Black Mountain R-13 sheep wool 16″ rolls (we used just under 9 rolls for our 146″ wheelbase Nissan NV2500 high roof van)
- Low-VOC spray adhesive (we used 3M Super 77, which isn’t the “greenest” choice, but at least it’s low-VOC)
- 2-4 gallons Noxudol Sound Damping compound (the amount will vary depending on your van size and how much surface you choose to cover)
- Paint brush (preferably an older brush)
Before You Start
The first step is to deep clean your van. Deep, deep clean the van. Take out the floor mats and clean them, get deep into the crevices and clean everything. This is your new home and this is your only opportunity to do a truly deep cleaning of the entire van before you start your conversion. Be sure to identify any potential mold areas and spray with a mixture of bleach and water. Allow the van to air out completely for a couple days after spraying bleach before you start your conversion.
Identify and tape off the areas you plan to use sound damping. We recommend using this on top of any exposed metal that’s not going to have wood, paneling, or flooring surface on it, including entryways, wheel wells, and step areas by the doors. Depending on your flooring selection, you may want to cover your entire van floor with a layer of the Noxudol, but we didn’t because we added cork as part of our flooring installation. Using an old paint brush, spread a thick layer of the Noxudol on the applicable areas. Repeat for 2-3 coats and be sure to let the product dry between costs.
Start pulling apart one of the rolls of wool and use the small pieces to fill all the cracks and crevices in your van. Be thorough to ensure you’re insulating deep in every gap in the walls, floors, and even in the small holes in the ceiling and wall beams. These areas can be tricky to access (we took advantage of having our 11-year-old nephew with little hands helping us out!), but do your best to be thorough. There were some places in the panels surrounding the doors/windows where the holes were too small to access, so we actually drilled holes in the sheet metal to reach them. You want to fill as many of the small cavities as possible with wool. Don’t force too much wool in these areas, just moderately fill the spaces completely.
Screw in 1/2″ furr strips on top of all the wall and ceiling beams. This will give you something to attach the wall paneling to and provide more space to fill with insulation.
Spray the wall and ceiling crevices with adhesive. Stick the roll of wool to the walls and ceiling. Spray each small area as you go. Use as little spray adhesive as possible and wear a mask. It’s very sticky so it doesn’t take much. It’s just meant to hold the material in place until you get the wall panels up.
For a completely non-toxic option, you could also take painters tape and criss-cross it over the wool to keep it in place. The wool comes in 3″ thick rolls. That will be the thickness of the insulation around the interior of the van. You don’t want to squish the wool too much because it’s supposed to be installed at the thickness it comes.
Tip– Be sure to previously identify and mark where you will have your vent fan, AC, windows, or anything else that will be cut into the metal of your van. You’ll want to block off these areas so you don’t insulate over an area that’s going to be cut.
In order to save as much head room as possible, we decided to only insulate the floor a small amount. Rather than raise the floor up, we just utilized existing space. There was the very small 1/4″ gap in the existing floor ridges that otherwise would have been dead air space. We rolled small pieces of the wool between that floor ridge. Next, we installed our 3/4″ plywood subfloor directly on top of the beams and small rows of wool. We added extra insulation when we installed our camper van flooring, by adding a layer of cork underlayment below our linoleum flooring.
Once the van is covered in insulation, you’re ready to put up the wall paneling. We recommend doing this step soon after completing insulation, so the insulation doesn’t become loose and fall down.
I’m not going to lie, it smelled a little like a petting zoo at first! After a week or so, all the essence of barn animals was gone though luckily. Now, we’re loving the wool insulation. The van stays cool when it’s hot and warm when it’s cold.
What type of insulation are you using for your camper van conversion? We’d love to hear your comments and suggestions!
Loved reading your blog post about why you selected sheeps wool over all others.
I was 100% sure that I was going to use Earth Wool insulation but after reading thoroughly through your post I’ve changed my mind.
I’d love to know more about how your van is dealing with condensation (in winter of course) between the Wool and metal skin if you can see that?
I’m assuming that if the Wool can cover every surface area of the outer metal skin then it would be very hard for moisture to find its way there and in-turn stop condensation building?
Thanks again for your SUPER helpful blog and can’t wait to hear back from you.
Hey Anthony! Thanks so much– I’m stoked that this post was helpful to you! So far, the wool has kept the van nicely insulated and I haven’t noticed much condensation inside. I recently removed some of the wall paneling to fix something behind it, and the wool insulation inside the wall cavity was dry– no moisture or condensation. Since I didn’t use a vapor barrier, the metal is able to breathe and moisture can flow in/out without getting trapped inside the walls. So far, it’s been working great! Let me know if you use wool– I’d love to hear about your experience with it!
Do you have vents on the interior or exterior of the van for the moisture to escape or?
Yup I have a fantastic vent fan https://amzn.to/2Wgp8GD
I really like what you are doing and that you build the van with sustainable materials. But in my opinion wool is not a good solution regarding how it is “made” and how sheep is treated during shearing. I have seen lots of videos where they had big cut outs in their skin, so I decided that I don’t want to use wool anymore.
You have mentioned hemp – this seems a good solution for me so I’ll try to get this for our van somewhere.
Thank you for all the hints in your blog.
You might want to look into Roxul if you haven’t done your project yet. It’s supposed to be mold and fire resistant and is mineral wool, which is NOT an animal derived product, rather is derived from molten glass, stone or slag (industrial waste) that is spun into a fibre-like structure.
Hey, thanks for your comment! I think Roxul would need to be easily manipulated so it could fit into all the tiny crevices of the van. Also, the batts would need to be cut down since the van cabinetry/walls aren’t made with 2x4s but thinner plywood. Thanks!
I used Roxul in my basement, and it is easily cut and manipulated. Batts can be cut with a serrated knife through the center to make two full size batts at half the thickness for an application like this. You’ll lose some of the RF value and sound deadening, of course, but it still should be sufficient for a van project.
Thanks for your input! I can’t speak to Roxul because I am not familiar with the chemical composition of the product. I will say that I am very happy with the sheep wool batts I used in my van!
Lucy & Charlie
Hi, Thanks so much for posting about how you did this. My partner and I are ready to order wool insulation and wanted to check the appropriate thickness. Are you happy with the insulation provided by the 3inch wool panels that you have? Have you been sleeping in the van in hot and cold temperatures? Would you advise any adjustments from what you did? Thank you for any advice you can share.
Hey there, wool works well in cold & warm climates, but when it’s really cold you’ll definitely need a heater. Your biggest heat loss will be your windows, so have really good window covers or fewer windows. It gets hot in the van, so ideally you won’t be inside the van in these extreme temperatures. Hope this helps!
While Roxul/Rockwool’s batting advertises its “greenguard” status, it is not green. The reason it is formaldehyde free is because they’re vacuuming it off the batting and shooting it up their stacks at their factories. They’re trying to build a Rockwool batting behemoth in Ranson West Virginia. The permitted air pollution for the proposed factory is unacceptable. The enormous reliance on coal, gas, and toxic chemicals at the molten basalt rock and slag factories is unsustainable.
Hi! I hope my post isn’t confusing– I did not use Roxul in my van and am not a proponent of doing so. This is an installation guide and review for sheep wool insulation. Thanks!
Green Building Techniques
Thank you for writing this awesome article. I’m a long time reader but I’ve never been compelled to leave a comment.
Hi Janice! Thank you so much for commenting– it really means a lot! It’s great to hear that this article has been helpful!
thank you for this post, I’m planning on getting a Sprinter soon and this non toxic insulation seems perfect. I haven’t seen anybody else use it but im guessing they aren’t concerned with the toxicity of their insulation, which they should be! thank you again!
Thanks Danny! I’ve been really happy with how the wool insulation has worked out so far. Congrats on your future project!
That seems to be the standard between efficiency, non-toxicity, hydrophobic material.
Hey! A lot of people have great luck with Thinsulate and I think it’s a great choice! I personally like that wool is not synthetic so you know exactly what you’re getting. Thanks for your comment!
Great article, thanks. I have been wondering about how to do that. What i would like to know is what you chose for wall and ceiling paneling (and maybe why you chose it). Thanks
Hi Ken, the wood paneling is very thin birch tongue and groove that you can purchase at Home Depot. I chose it for the texture and because it’s extremely thin, so won’t take up much wall-to-wall real estate. Thanks!
My partner and I are strongly considering using sheep wool for insulating our Mercedes Metris. I was nervous about the long-term moisture control properties of wool, especially considering it will be placed next to the cool metal of the van (or in some cases, a sound deadening material). Comforting to hear you say that the wool area was still dry and problem-free last December when you had to remove part of the paneling. Now that it’s been a year, are you still happy with your insulation choice? Also, for all those little holes would you recommend using fine pieces of wool or perhaps going with a gaps and cracks spray foam? And are you familiar at all with Havelock Wool insulation products? I am curious if there is a difference amongst the different companies.
Thanks so much! Appreciate the information in your blog!
Hey there! I’m happy with it but unfortunately I don’t really have much that I can compare it to– I’m not sure if other insulation would have been more warming or not. It would be really cool to do a van experiment and see which insulation really keeps it warmer. I haven’t had any moisture issues though! Best wishes and thanks for following the blog!
Have you compared wool to hemp insulation (with lime)? I like the idea of non-toxic insulation and was curious if it would he a good option.
On a side note, either wool or hemp is an organic material and when coupled with the metal from the van, may create an orgone accumulation effect. This is a huge benefit of your choice to choose a natural material.
Hey, thanks! I’ve heard hemp wasn’t as moisture-resistant as wool, but I didn’t do a ton of research about it so I can’t say for sure. I’ve heard it’s a really common selection for eco builders!
Hi I’m new to the campervan conversion world and have lined my VW T5 with neroprene and then sheeps wool.
Loved the article and I’m so glad I found a website that showed a conversion using sheeps wool!
I’m about to start the tailgate and line that with the wool too.
I’m just concerned about the van being too insulated. Is that even a thing?
Also, I’ve seen so many people then add some reflective material on top of the soft insulation that they have used, whether it be fibreglass, or other materials.
Is that side really necessary or can I just install panels on top of the sheeps wool and it be pretty insulated?
Any help would be very much appreciated as sometimes I feel a bit overwhelmed with what I’m doing.
Thanks so much.
Hey Louise! Unfortunately I don’t know anything about Neoprene and how it affects moisture. I recommend watching the video in this post because it addresses your reflectix question– using reflectix that way is not effective without an air gap. I recommend insulating your van as much as possible but look into the moisture issues as well. Thanks!
Hey! I don’t know if my comment went through yesterday, but I recently bought a transit van with my partner and I am trying to make a case for sheep wool insulation. I strongly believe the most environmentally conscious avenue possible is the way to go. Do you have a pricing esitmate for the sheep wool you used similar to the sound proofing cost you provided here? It would be greatly appreciated (sheep wool insulation prices seem hard to find)!
Hey! I don’t remember off-hand but if you google the product, you can see prices. I used just under 9 rolls: Black Mountain R-13 sheep wool 16? rolls. Thanks!
Hello! I’m planning to use Black Mountain wool in my van conversion, but I have a fiberglass top. It is a totally smooth surface with no spaces to stuff the wool like the roof of your van has. Any ideas for how to ( or if I even need to) insulate my fiberglass roof?
Hey, I don’t know the R-value for fiberglass but heat rises and I would definitely recommend insulating the ceiling. We installed wood furr strips, insulated between them and then put tongue and groove boards on top of that. Best of luck on your build!
Hi! Good post! The sheep wool is really interesting and I’m probably going to use it in my new van. Just like to ask have you checked under the panels or noticed if there is any mold, rust or condensation?
Thanks a lot! 🙂
When you decided on sound proofing is there a particular reason you chose Noxudal sound dampening compound versus noico sound deadening mats? Thanks.
Hi Charlene, the compound is literally thickly painted on the van so I think it does a good job with it’s thorough coverage. I bed both would be great too! I don’t really have much issue with noise in the van while driving or otherwise. Thanks!
I’m working up a design for a non-toxic van with a few extra criteria, since I’m chemically sensitive. Very happy to find your site, as I’ve been considering both sheep’s wool and marmoleum. I’m still stumped about material for siding and ceiling, since I can’t do plywood in any form (plywood, even “formaldehyde free” plywood, off-gasses formaldehyde, my achilles heel). I’m considering using some kind of metal screen mesh. Curious what you might think of this idea, and/or if you have any other suggestions? (I’m not handy at all, so I may be missing something obvious!) Thanks, and please keep up the good work!
Hey, thanks so much for reading! I’ve seen metal used as an interior wall on one van in Montana and it appeared to be rusting a bit– metal can’t breathe at all so you could have some trapped moisture issues. That said, I don’t know anything that specific metal screen material you mention– do you know if it allows moisture to move through? There are some fantastic green building blogs out there that might have good suggestions– maybe if you search outside the van conversion world, you can find your answer. This website is great: https://www.greenbuildingadvisor.com/article/helping-people-with-multiple-chemical-sensitivity
I’ve been planning to insulate my van with wool, then had some second thoughts today when I found a moth had eaten some holes in one of my wool scarves! Have you had any trouble with clothes moths in your insulation?
On a related note, did you consider kapok as an insulation? I’m wondering about how it handles moisture, and how it compares to wool as an insulator. (And, whether moths like it too!)
Hey! I don’t see how moths could ever access the insulation since it’s completely sealed in by your wall material. I’ve never heard of anything like that before– denim is a common insulation material as well, maybe research denim and moths? Off the top of my head, I don’t think it’s a true issue unless there are gaps where creatures could get into your insulation? I haven’t had any issues though! I’m not familiar with kapok cotton — my main questions would be R-value (how well it insulates) and if it retains moisture. Hope this helps!
I cringe when i see folks using reflectix incorrectly. If you ever buy a used van, it’s good to ask what’s inside the walls before you purchase, you could have a hidden nightmare. Wool is the only one i trust completely. Even though spray foam works great, it’s a pain to install, and not very natural…lol. Being from New England I grew up with wool, and summited Mt Rainer in wool, it’s never failed me. I’ve had vans before, but never insulated them, the new one (just purchased) will be insulated with Havelock Wool
Hey Paul, thanks for your comment! I’m stoked to share that I’m actually partnering with Havelock Wool! Great product, great people. Happy vanning!
Kathleen Dose Koehl
Another natural insulating fiber is alpaca. It’s actually about 4 times warmer than wool, as it’s hollow. There is a company in Ohio that produces insulation batts.
I’m curious why you used the linoleum instead of just cork?
Thanks for your thorough information! I’m hoping to make a low-toxin build soon.
Good to know! I haven’t heard much about Alpaca but that’s definitely something to look into.
The cork underlayment I have below my linoleum is very thin and not used for flooring on its own. Cork flooring often comes in snap planks, which are as thick as wood flooring and wouldn’t work for my needs of maximizing head space as much as possible. I don’t have experience with thinner cork roll-out flooring and it’s not truly water-resistant like linoleum. Hope this helps!
I am very interested in a natural wool product as well,
BUT, the question I have is, in warm weather climates, do you find the wool to be able to keep the interior of the van cooler, or does it just slow down the heating up process?
Hey there, wool works well in warm climates. Your biggest heat loss will be your windows, so have really good window covers or fewer windows.
You left out one KEY component: VENTILATION!
This will eliminate stale, moist air, which is the first defense against mold and mildew which is an issue that attacks most environmentally friendly materials.
A couple of vents (one can be passive the other active with a reversible fan) strategically placed front and back should do the trick.
I was wondering if anyone has tried using mesh tape and a type of concrete like thinset, rapidset cement all or Portland cement on the floor of the vehicle ? How much weight will it add for instance a 1/4” layer, and would it help keeping the heat from catalytic converters, exhaust, transmission and engine heat from making the cabin hot..? haven’t been able to find anything on the web about this. Anyone ?
Hey Rodrick, Interesting idea. From my experience with concrete in various types of structures and from first-hand experience seeing what a camper van goes through when driving on dirt and gravel roads, I strongly believe concrete would crack and you’d have a mess on your hands. I’ve never noticed heat any from the engine, ever. It sounds like a lot of work to try to solve a problem that doesn’t exist and only causes several problems in itself. Sorry for the bluntness, lol, but I’m being honest. Happy building!