Vanlife Insulation Guide: Make an Educated Decision

Vanlife Insulation Guide: Make an Educated Decision

Van insulation... welcome to the most controversial topic since the creation of #Vanlife! After years of passionate debate, Internet experts still can't agree on the best insulation for DIY van conversions. Let's hit pause on the emotional debate and do it our way: with theoretical analysis and real-life follow up.

Disclosure: This post contains affiliate links, which means that if you click a product link and buy anything from the merchant (Amazon, eBay, etc.) we will receive a commission fee. The price you pay remains the same, affiliate link or not.

Portrait-FarOutRide-Isabelle-Antoine-Van

1- Jumping to Conclusion

We’re not fans of shortcuts and hasty decisions, but there you have it. After 2 winters of full-time vanlife at temperatures as low as -22F (-30°C) and up to 95F (35°C), we recommend insulating your van with:

Thinsulate

ford-transit-camper-van-thinsulate-installation-1

We personally used Thinsulate in our van. It has kept us warm, no mold, no bugs, since 2017. It’s SO easy to work with, and there are no chemicals added (as fire retardant or bug prevention). We and our van love it.

(Free shipping to USA and Canada. USA orders are tax free and ship from USA warehouse. Canadian orders are subject to taxes and ship from Canadian warehouse.)

That being said: knowledge is power! Make your own conclusion about van conversion insulation by reading the whole thing below…  🙂

2- Theory

2.1- Heat Transfer 101

The goal of adding insulation is to combat heat loss. Heat loss happens because of heat transfer (a.k.a. heat flow). Heat is always transferred from warm to cool and continues as long as there is a temperature difference; a larger temperature difference means more heat transfer potential.  There are 3 heat transfer mechanisms: Conduction, Radiation & Convection.

Credit: machinedesign.com

Conduction

Examples:

HOW:

Energy is stored in the vibration of atoms. More heat = more energy = more vibrations. The collision of atoms between each other transfers heat.

Insulating for conduction:

The more dense a material, the closer the atoms are from each other and the more they transfer energy to their adjacent atoms (by physically colliding with each other). Therefore:

Less dense materials are a better insulator for conduction.

Radiation

Examples:

HOW:

Any hot (or warm) object radiates electromagnetic waves and can heat up other objects at distance (and therefore lose heat themselves). Energy is transferred through the electromagnetic waves, therefore, thermal radiation can happen through vacuum (without the presence of matter).

Insulating for radiation:

A white shiny surface is poor at absorbing and radiating heat. It is, therefore, a good radiant barrier.

Convection

Examples:

HOW:

Heat is “transported” from one part of a fluid (or gas) to another by the bulk movement of the fluid itself. Hot regions are less dense, so they tend to rise and are replaced by cooler fluid from above. 

Insulating for Convection:

Insulating hollow structure (i.e. frames) and eliminating air gaps minimizes air movement and reduces heat loss through convection.

While heat transfer can be separated in to 3 separate mechanisms, heat loss normally implies all 3 of them together. For example, a hot cup of coffee:

  • Heat is transferred from the liquid to the cup surfaces (conduction + convection from the circulation),
  • From the cup to the air and objects nearby (convection+radiation), 
  • From the cup to the cold table underneath (conduction),
  • Blowing on coffee to cool it down (convection).
  • (Heat is also lost through evaporation -change of phase-, but that’s out of our scope).

2.2- R-Value

Insulation materials are good at resisting heat flow. To quantify how good an insulating material is and to allow easy comparisons between them, a neat dude came up with R-value.

R-VALUE

R-value denotes the capacity of an insulating material to resist heat flow. The higher the R-value, the greater the insulating power. It is normally noted (for example) “6.5 per inch“, which means applying one inch thickness of the material will provide 6.5 R-value; applying two inches will provide 13.0 R-value; and so on. R-value takes into account all three heat transfer mechanisms (conduction, radiation, convection). R-value is determined with the ASTM C518 test (“Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus”).

2.3- Condensation and Moisture Control

Vapor Barrier or not?

The purpose of a vapor barrier is to prevent moist air (from inside the van) from migrating towards cold surfaces. The idea is that moist air from respiration, cooking, drying gear, etc. won’t reach cold surfaces, thereby eliminating condensation issues. However, if, for any reason, moist air makes its way past the vapor barrier, it would be very hard to dry that moist air because it would be sandwiched between two vapor barrier layers (remember that metal is a vapor barrier too).

Even if one could achieve the perfect vapor barrier (which is unlikely, sorry), there are paths for outside air (charged with moisture) to infiltrate, and there are potential leak points as well:

Therefore, we believe that moist air will inevitably come in contact with cold structure, so our approach is to let the insulation layers “breathe” (no vapor barrier).

Condensation and moisture is quite complex, there is much more to talk about… we think this article should help you understand the phenomenon and help you make a better informed decision about your insulation:

CONDENSATION AND MOISTURE IN A VAN | WHY IT HAPPENS AND HOW TO CONTROL IT

2.4- Thermal Bridges

A thermal bridge is a path of least resistance for heat transfer. In other words, it’s a path for heat to “cheat” your insulation and find a way around it. It normally occurs via conduction through a dense material (such as metal).

Take for example the following picture. We added Thinsulate pretty much everywhere, except on the frames and pillars where we will attach our structure (cabinets, etc.). All the exposed metal is considered a thermal bridge, and heat will flow through it around the Thinsulate.

To mitigate the thermal bridges, a thermal break is added. We added LOW-E (EZ-COOL) since it’s pretty resistant to compression (applied by the structure attached to the van’s frames).

That’s important, especially if you’re using 80/20 aluminum extrusions for your build (structure, cabinets, etc.). Indeed, attaching the 80/20 aluminum directly to the van metal creates excellent thermal bridges; as a result, the 80/20 inside your van will be almost as cold as the van metal!

2.5- Air Loops

Hot air is less dense, so it tends to rise and be replaced by cooler air from above. That’s called an air loop and it’s a phenomenon that happens in non-insulated, hollow structures, like in the frames and pillars. So, to the question: “Is it worth shoving insulation inside frames knowing heat will find a way around (thermal bridges)?” We think it’s worth it. The total heat loss of your van is the sum of all the small pieces and bits… It all adds up! 

Air-Loop-Convection-Heat-Transfer
Van-Insulation-Convection-Hollow-Structure

3- Van Insulation Materials

At this point, we’re still on our quest to find THE BEST van insulation material… But in order to find out, let’s review our different options:

ford-transit-camper-van-thinsulate-installation-1

Thinsulate

PROS

CONS

Bottom line: it’s a popular tried-and-true product that gives an added value to higher-end builds.

Polyiso Rigid Board

PROS

CONS

XPS Rigid Board

PROS

CONS

Spray Foam

PROS

CONS

Rockwool

PROS

CONS

Reflectix

Once upon a time, someone decided to insulate his van with Reflectix and blogged about it. Then everyone started using it. 

By now, we know Reflectix is a very poor insulator. And on top of that, it requires an air gap in order to be effective.

It’s a good option to make your own window covers (to reflect the sun), but we prefer LOW-E as it is more resistant to tear and doesn’t have that annoying foil noise.

Low-E (EZ-Cool)

PROS

Low-E insulation (formerly EZ-COOL) is sold as a “radiant-barrier”. It doesn’t have much R-Value, but it’s convenient to use as a thermal break and for insulated window covers.

From Heros to Zeros:

Van Insulation Recycled Denim

Recycled Denim

Why we don't recommend it

It’s hydrophilic: it absorbs and retains moisture. People sometimes attempt to enclose it in garbage bags only to find out later that the bags are torn and the insulation is soaked or moldy.

Fiberglass

Why we don't recommend it

It’s hydrophilic: it absorbs and retains moisture. People sometimes attempt to enclose it in garbage bags only to find out later that the bags are torn and the insulation is soaked or moldy.

Lizard Skin and other insulating Paint

Why we don't recommend it

By now we know that efficient insulation materials are low-density. A coat of paint is everything except low density…

The manufacturers don’t provide any data (i.e. R-value, etc.) to backup their claims; there’s probably a good reason why (it would be fairly easy to test and publish data).

According to this Scientific American article, the EPA does not recommend insulating paint: “We haven’t seen any independent studies that can verify their insulating qualities”. They noted some heat gain reduction on surfaces directly exposed to sun only, and that “the reflectivity of the painted surfaces decline considerably with time”. It’s all about reflectivity, not insulation capacity. Are you really gonna paint the exterior or your van with insulating paint..?

Until independent studies show a benefit of insulating paint through standardized test, save your money and your time.

4- Our Insulation Strategy

Going from theory to real-life implies making compromises; there is no perfect solution! The best vanlife insulation is not just about R-Value, it’s also about:

  • Ease of installation for the average DIYer
  • Risk of messing things up (i.e. warped van panels)
  • Condensation and moisture control
  • Conformity to curved and uneven surfaces
  • Material properties (i.e. maximum temperature, resistance to pressure)

With that in mind, here is how we insulated our campervan:

4.1- Floor

To be efficient, any compressible insulation material (thinsulate, wool, etc.) must be fully expanded. As a result, they’re not ideal for floor insulation. On the other hand, XPS is an excellent insulator, provides a solid and flat foundation for our floor, is quite cheap, and is readily available at your local hardware store.

So, does it work in real-life? Definitely! We installed our Webasto so it blows hot air in our living space near and parallel to our floor; as a result, the floor is nice and warm, even in sub-freezing temperatures. But don’t get us wrong: the farther you go from the Webasto, the colder the floor gets. Cold air falls, remember? So even a perfectly insulated floor won’t be nice and warm all over unless it’s heated somehow. No, we don’t think a radiant heated floor is necessary (but could be a nice luxury); a pair of slippers is just fine and much more energy efficient!

We chose XPS Rigid Board C-200 to insulate our floor. The C-200 is rated 20PSI capable; human footprint = 16 PSI.

Here are our layers from bottom-up:

  • 1/2″ thick XPS (to fill the corrugations)
  • 1″ thick XPS
  • MLV -not shown in the picture- (noise insulation, but we’d skip that layer if we had to start over)
  • 1/2″ thick Plywood
  • Vinyl Flooring -not shown in the picture-

We documented EVERYTHING about our floor installation here (insulation, sealing, bonding, plywood, vinyl, etc.):

4.2- Walls, Ceiling, Overhead cabin & Sliding Door

Installing Thinsulate insulation in a DIY conversion is a piece of cake: there’s no mess, no risk of messing things up, it’s not permanent, and it’s easy to work with. You’ll be all done in a weekend. Here is how it goes:

  1. Cut Thinsulate to size (using tailor scissors)
  2. Apply 3M 90 spray adhesive to the van wall and on the white face of the Thinsulate
  3. Wait 30-60 seconds for the adhesive to become tacky
  4. Press the Thinsulate against the wall
  5. That’s all!

How does it perform in real-life? Since we moved full-time in our van (2017), we’ve had everything between -22F (-30°C) and +95F (+35°C), and we’re in a good position to say it’s a tried-and-true van insulation material. If we had to build another van, we’d use Thinsulate insulation again without any hesitation.

ford-transit-camper-van-thinsulate-installation-18
Walls
ford-transit-camper-van-thinsulate-installation-13
Overhead Cabin Storage
sliding-door-after-thinsulate
Sliding Door
Thinsulate installed
All done. That was easy!

We documented EVERYTHING about the installation of our Thinsulate insulation (walls, ceiling, overhead cabin storage, sliding door, etc.) in the following article:

We covered all the remaining exposed metal and about 50% of Thinsulate surfaces with LOW-E insulation; this is to create thermal breaks and add some radiant barrier. We didn’t completely cover the Thinsulate in order to let it “breathe” (the LOW-E acts as a vapor barrier). As usual, we documented the whole thing:

4.3- Windows

You can spend a lot of money and time on the best insulation, but remember that glass is an excellent heat conductor (in other words, a horrible insulator). You can make cheap & dirty Reflectix covers to reflect the sun in summer, but if you are skiers like us, you will want something that performs better… To minimize heat loss during winter, we made insulated window covers out of low-e + thinsulate + fabric. They make a HUGE difference in sub-freezing temperatures, and they’re just plain essential below 5F (-15°C). Here is how we made them:

5- On Second Thought

You can read our second thoughts in each respective installation article listed above. But to sum it up: we would choose exactly the same van insulation strategy if we had to start over! It has served us very well.

Want to know more about winter vanlife? Driving in snow, 4×4, FWD vs RWD, electricity, finding water, finding camp spots, etc.? We wrote a debrief after our first winter full-time in the van (and plan on updating it every winter):

Want More?


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About us


NICE TO MEET YOU.

About-Us-Narrow

Hello! We’re Isabelle and Antoine 🙂 In 2017, we sold our house (and everything in it), quit our engineering careers, and moved into our self-built campervan. We’ve been on the road since then, and every day is an opportunity for a new adventure; we’re chasing our dreams, and hopefully it inspires others to do the same!

94 thoughts on “Vanlife Insulation Guide: Make an Educated Decision”

Heads up! As of summer 2021, we are currently travelling to Yukon (and hopefully Alaska) and have very limited access to Internet. As a result, we might not be able to answer all comments. Thanks for understanding and see you on the road! -Isabelle and Antoine

  1. Hey all,

    LOVE the site and purchased your electrical guides, etc a few weeks back and just got the handwritten envelope with stickers earlier this week! So kind.

    I am using a ton of your info for my build (and the affiliate links so you get compensated) and I’m leaning towards doing all of your insulations methed, except with Sheepswool in lieu of Thinsulate. Sounds like with Thinsulate that you use 3m tape, but curious about your recommendations on adhering sheepswool?

    Reply
  2. Hi, your website is amazing. I just bought a Van and will start with my conversion soon and this website is by far the best i came across.
    I will became a Patron because you definitely deserve it.
    Before starting with my insulation i do have a question, did you considered X-trem insulation material? i read that some people are choosing this one and now i’m trying to decide between X-trem or Thinsulate.
    I’d like to hear your thoughts about X-trem.

    Best regards and stay safe,
    Bruno

    Reply
    • Not familiar with X-trem, but I’d stick with tried-and-true insulation. Thinsulate has been around for a while; it’s SO easy to install and it just works!

      Cheers

      Reply
  3. Hi!
    Did you use EZcool because it was better than nothing for your thermal bridging? It seems it works just like Relfectix which everyone seems to say is ineffective for conductive insulation? I’m debating whether I should do this since I don’t intend to winter camp.

    Also, I am converting a van whose ceiling is almost entirely sunroof and the spaces that hold the sunroof when retracted. I cannot actually get to the metal roof of the van. So I’m wondering if Reflectix/EZcool might actually be appropriate solution in this case? It would mostly be against air or plastic (the case that holds the sunroof). There is about 2″ of space behind that until reaching the metal roof.

    Thanks for all this detailed information. It is so well explained and organized and really helpful!

    Reply
  4. I’m from Australia and trying to find a product that is 100% wool unfortunately I’ve only been able to come across a 40/60 ratio wool to polyester!

    From my readings it sounds like the wool holds up on its part on absorbing the moisture and warming up and preventing condensation….. still a tad nervous about the poly.

    Any informative information would go a long way thank you so much for your site and knowledge through out your journey!!!

    Raul.

    Reply
  5. Hey guys, i’m so impressed with what you have achieved! I’ve finally Bought a Ford Transit myself and will be converting it in Scotland before driving out to Italy for the winter season. I was wondering if you considered using hemp as insulation at all? Also do you if you are able to buy Thinsulate in the UK. You have inspired me to follow my dream and being a snow searcher myself, you have become my role models!

    Any help would be appreciated

    Thanks! Chris

    Reply
  6. Great article! Unfortunately, it’s hard to find Thinsulate in Europe..
    A lot of people over here are using cork as a base layer, have you heard anything about the benefits / drawbacks?

    Reply
    • It just a wool based product so why not use Diall recycled plastic insulation from B&Q it’s the same K value but thicker so much better R value and cheaper than thinsulare. Result!

      Reply
  7. Thanks again for the wealth of knowledge you two share with the world!

    I’d like to hear your thoughts on professional spray foam applications. Is there a condensation reason or other reason that made you not use spray foam?

    Thanks!

    Reply
    • It’s mostly because we felt Thinsulate is good enough and much easier to install. Spray foam has excellent R value, but there’s a risk of warping the sheet metal; if you’re confident you can install it properly and avoid the warping, I don’t see any issue with spray foam.

      Reply
      • Maybe I missed this but I’m wondering about insulation if you are in warm/hot/humid climates 90% of the time? I know some people say not to insulate but I’m certain those people have never spent a summer in the South. haha! Any suggestions would be helpful– I’m afraid I read too many blog posts and articles. I’m a bit lost now…

        Reply
        • It’s still the same strategy! I’d personally insulate it FOR SURE; the only reason you wouldn’t is if you’re on a very tight budget… A layer of Thinsulate just like we did here would works just fine: https://faroutride.com/thinsulate/

          And I’d add:
          – Choose a van with light color (white being the best);
          – Make sure to have window covers: https://faroutride.com/insulated-window-covers/ (If it’s for hot climate only, you could skip the Thinsulate layer to save $…).
          – Good ventilation

          Good luck!

          Reply
          • Thank you so much for the information! I don’t foresee Thinsulate in my future. Even if I could get past the incessant marketing campaign by the owner, Thinsulate is on the expensive side. I happen to have access to 3 sheets of polyiso. No idea if that is enough to cover my van (Promaster 159″ ext. high roof) but will give it a go. If I didn’t have the polyiso, I might have found a way for the Thinsulate to fit into my budget— just not a fan of people posting on boards about products while conveniently leaving out that they are the owner of the company. It feels like a lie of omission. That said, enough people attest to its viability but, for me, it causes me to doubt the quality. I think I worked in research and forensics for too long and am always looking to see if there’s something behind motives. haha If you have a brilliant product, stand up and say “hey! I have a brilliant product and this is why…” Sorry, I digress.

            And I shall add:
            1. I blew it on the van color… definitely not light but the price was good! lol
            2. Working on Window covers. You are right about windows and heat! OY! I had planned on adding more windows but the number has been cut down significantly due to the heat blaring through windows! Planning on having all windows tinted once I have one (!) window installed.
            3. Two Maxxair fans are in the plans. Lord knows, I’m gonna need it!

            Your website is so very helpful to the van life community. Thank you for what you do!

  8. Hi~
    Could you tell me how many roll of the “Thinsulate Acoustic” you used for for your Transit?
    and on Other every product like How much, How long ( of gas pipe) … that is what I want to know.

    Reply
  9. Hi Guys
    Absolutely fantastic website, thanks for such well documented resource.
    We are just about to start our build in the UK
    I have many questions that no doubt will be answered via the site content. However I am curious why when constructing, at insulation and wall cladding stage you chose not to cover the underbed storage area as you have the main parts of the van with insulation and cladding. Has there been any cold air, condensation issues with the garage area.

    Look forward to your response

    Kind regards
    Paul

    Reply
  10. Is there an alternative adhesive to the 3M90? Amazon is estimating a 1 to 2 month shipping time from China. I assume this is because of the viral outbreak there, and if that is correct it could take even longer to get the supply chain up and going again. I would really appreciate any suggestions you could make.

    Thanks for an awesome website. Easily the best build/conversion information I have seen.

    Reply
  11. Hi,
    Do you think Thinsulate would make a good insulator for HVAC hard metal ducts? I would like to avoid using regular fiberglass duct wrap. My thought was to wrap them with a layer of thinsulate then with a layer of reflectix or ez-cool as a vapor barrier. Or I could use a layer of thinsulate and then a layer of sheep wool since the wool acts as a vapor barrier of sorts by absorbing the moisture into its fibers.

    Reply
  12. We are doing our floor now and I have a question for ya.
    I am doing 1/2″ closed cell foam between the ridges on the floor, and then another 1/2 board to sit on top of the ridges and the first 1/2″, and then plywood as the subfloor.
    My question is, should I put down some wood planks in the floor instead of the 1st layer of insulation to steady the floor more and have more wood for the cabinests to screw into? Or does foam on foam atop the ridges, and plywood have enough grip that I can screw into that and be fine?
    Thanks!!

    Reply
  13. bonjour,
    je veux transformer une petite van genre Transit connect,
    je veux l’utiliser principalement l’été mais aussi l’automne au Québec environ (-5 nuit)
    que me suggérez-vous comme isolation, est-ce que le Thinsulate nécessaire ou juste une barrière comme le ez-cool serait suffisante.

    merci

    Reply
  14. I researched and found this awesome high R-value insulation that I wanted to tell y’all about. I feel like I have stuck gold with this insulation’s high R value of 22 and with how thin it is, especially for insulating something like the floor. But from feedback from other van people, I’m starting to get confused because they don’t seem impressed. Am I missing something that makes this insulation not awesome?

    Prodex 10M:
    https://www.insulation4less.com/insulation4lessproduct-62-prodex-total-10m.aspx

    Installation Advice:
    https://www.insulation4less.com/insulationmethods-35-van—sprinter-or-cargo-click-for-installation-instructions.aspx

    Reply
    • That’s EZ-COOL, basically. Manufacturer attribute them high R-VALUE because of the radiant barrier, but in practice they cannot achieve that. REFLECTIX has a similar story…
      We used EZ-COOL as thermal-break barrier (and would use it again), but I wouldn’t recommend it as your main insulation (definitely not R22 as advertised).

      Thanks for the heads up! Cheers 🙂

      Reply
  15. Great article. Thank you! I am insulating my first van soon… I think… Dare I try living in a van without insulation…?

    Anyways, I want to suggest a minor correction of your description of radiative heat transfer:

    You said: “no particles move when heat is radiated”

    Particles indeed move when heat is radiated from a body. Electromagnetic waves are comprised of photons, which the physics community considers a particle. I understood what you were driving at with your statement but technically it’s false.

    To be more accurate you could replace:

    “Unlike other mechanism (conduction, convection) no particles move when heat is radiated; therefore, heat can be transferred through vacuum.”

    with

    “Unlike other mechanism (conduction, convection) direct physical contact between two objects is not required in order for heat to be transferred from one object to another.”

    Source: Wikipedia and I am a mechanical engineering dropout

    Reply
  16. In process, and loe your website. I have a mid roof 2019 Transit. Trying to conserve headroom. Can I use 1/2″ XPS on top, instead of one inch and 3/8″ plywood. This would save5/8″ inch height. Would 3’8″ ply be sufficient for lower cabinet bolt down ?

    Reply
    • Do you plan on using your van in winter (i.e. for skiing)? If not, you could save even more space by using this Minicell package (view on eBay). It fills the corrugations and the top layer (included in the package) is only 0.25″ thick (instead of 1/2″ as you proposed).

      – If using your van in winter, I wouldn’t go lower than 1/2″ XPS.
      – For the plywood, I wouldn’t go lower than 1/2″ to prevent warping & because 3/8 doesn’t provide much grip for the screw (for the cabinets).

      Cheers, hope that helps!

      Reply
  17. Love your website. By far the best put together and most informative vanlife site I’ve come across. I’m in the middle of my build now and trying to decide on insulation. I’m taking a two layer approach….thinsulate or sheepswool covered on top with sheets of .75 inch polyiso panels. The van will be almost exclusively used in freezing temps as ski rig. My primary concern with thinsulate is the health safety of product. I’ve looked at SDS and it looks like thinsulate a mix of polyethylene and polypropylene with less than 1 percent of some proprietary undisclosed magic sauce. I’ve ordered sample and seems inert…no smell, hydrophobic, doesn’t burn. Great stuff….but I don’t trust 3M and I don’t have enough of a chemistry background to understand how this stuff degrades, breaks down, flakes off etc etc. Sheeps wool seems like a great alternative expect for the problem of bugs….and maybe organophosphates retained in wool. Is there any testing with regards to plastics in thinsulate and potential endocrine effects? Sorry, I know this comes off as a bit overzealous but modern insulation for as effective as it is has a lot of unknown side effects that give me reason for pause. As far as polyiso…not perfect as it contains halogenated flame retardants but having foil taped all edges I feel it’s pretty well sealed up.

    Reply
    • Hi, I love the site and the work you’re doing, I bought my van last week and I will use it occasionally at least for a while, I’m not sure I’m ready to take on the full electrical system quite yet, instead I’m purchasing a goal zero because it’s much less of a commitment, I do have to insulate the van though, I will try to follow what you did, and here are my questions: Did you do electrical work first or insulation? Also how much harder would it be to do the electrical work later on top of the insulation?

      Reply

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