Van Conversion Guide

Insulation

Insulation is one of the most important and debated topics of any van conversion. It’s essential to stay warm and comfortable in cold weather, and it’s a semi-permanent decision — once you’ve put walls and a ceiling over your insulation, you’re not going to want to change your mind! The problem is that there’s just no perfect insulation material that suits every VanLifer’s needs. No silver bullets here! Even worse, there are a lot of misconceptions floating around the web, which makes the decision of how you’re going to insulate your van even more frustrating.

That’s why we’ve put together this guide to insulating your van. We’ve created an in-depth guide below for the most tried-and-true methods for insulating your van, and what we personally chose to insulate our van.

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Ultimately, it’s up to you to determine what works best for your needs. For some, insulation isn’t so important because they travel to warm places in the winter. For other VanLifers (ahem, us), they’ll spend their winters skiing in the mountains, so insulating the van is crucial for making it a sustainable, comfortable lifestyle. Note that if you’re planning to stay somewhere warm during the winter — you may not need to insulate much.

What to Look For in Insulation

The details of how and why to insulate — how heat transfer works, how insulation will combat it to keep you comfortable, and what we’ll look at to compare different insulation types.

What Types of Insulation Should I Use for My Van?

Here we list the pros and cons of five different types of insulation. If an insulation material isn’t on the list, it’s because either we don’t see it on many installations or we don’t consider it to be a very good choice (we’re looking at you, magic paint that allegedly insulates).

Our Recommendation

Part 3 explains what we decided to use in our van conversion and why we recommend it. If you don’t want the details, skip here.

PART 1: What to look for in insulation

Before we can talk about the best materials to insulate your van, we’ve got to talk about what heat transfer is. After that, we can get into how we’ll use insulation to combat that heat transfer. And finally, we’ll get into what to look for in insulation — its cost, strength, and more – so that we have a way of comparing different insulation materials.

Understanding Heat

There are two types of heat transfer you’ll want to insulate against in your van:

1. Radiation: heat that’s transferred through the air, like sunlight shining through your window and heating up the inside of your van.

2. Conduction: heat that’s transferred through a solid surface – like when you touch your van exterior on a hot day.

Understanding Insulation

To insulate against these two types of heat transfer, there are three ways you’ll want to consider to insulate your van:

1. Window covers
In the summer, you can use a window cover to bounce the radiation heat back outside your van to stay cool. In the winter, it will help to trap the heat inside. Reflectix or EZ Cool is a great material to make a window cover with.

2. Insulating van walls/ceiling/floor:
This will combat your van conducting the sun’s heat inside during the summer and will prevent heat loss during the winter. Since heat rises, you’ll want to put thicker insulation on the ceiling. There is no consensus on the best material for this, but we get into these details in Part 2 below!

3. Insulating thermal bridges:
Even after you cover your wall, ceiling, and floor with your insulation, any part of the metal frame of the vehicle that still isn’t covered can still transfer heat through conduction. A thin, insulating material like EZ Cool is great for this those last, little exposed parts of the metal frame that you couldn’t cover. (Don’t think this is important? Check out FarOutRide’s “About thermal bridge” article!)

We’ll leave the tutorial for making window covers in a separate guide — for the purposes of this guide, we’re zeroing in on how to best insulate your van’s walls, ceiling, floor, and mitigate the remaining thermal bridges. You’ll be spending your winters in the snowy mountains in no time!

5 Things to Consider

Here are the 5 things we’ll consider when choosing the best insulation for your van conversion:

1. R-Value: this is a material’s Resistance to heat transfer by conduction. Basically, the higher the R-value, the more insulating the material is per square inch. This unit also considers another important metric: space — an ideal insulating material in a van will pack a punch with a high R-value without taking up a lot of room.

2. Resistance to moisture, mold, mildew, and fire: living in a small space like a van means there will be moisture in your van — so you want a material that won’t invite mold and mildew to grow. Flame resistance is a bonus, especially if you’re planning to install the electrical system yourself (just sayin’).

3. Durability: unless you’re parking your van in your best friend’s backyard for the winter, you’re probably spending your days driving everywhere. Driving on roads causes a lot of vibration in your van – especially if you’re gunning for those high-demand BLM campsites off dirt roads. Your insulation will have to withstand that vibration without breaking apart or falling down.

4. Non-toxic: in a small living space, you really don’t want to be breathing harmful gasses and pollutants all day.

5. Cost and installation difficulty: ultimately, VanLife is about the lifestyle – not how decked-out your van is. We want something that does the job insulating well without emptying the bank account and doesn’t take too long to install.

No insulation material is going to get an A+ in all five of these categories, but you can use these metrics to figure out which one works best for your values. Let’s get into it!

Part 2: What Types of Insulation Should I Use for My Van?

Let’s dive into different insulation materials:

Reflectix

Let’s start with the most misunderstood insulation material on the internet: Reflectix. It’s cheap, it’s easy to install, and it does almost nothing for conductive heat on most installations. Reflectix is essentially thin bubble wrap with a reflective coating on both sides that acts as a radiant heat barrier.

Properly installed, it has an R-Value of 4.4 – pretty good, although some have claimed that’s exaggerated. But installed improperly, its R Value is only 1.1 (very low). It’s non-toxic, but if exposed to flame, it will combust and drop flaming liquid — once if the flame is removed, it will self-extinguish.

Reflectix also has a close cousin, EZ-Cool, that is very similar and is also used on a lot of conversions.

To install Reflectix the correct way, you’ve got to have at least a 3/4 inch of an air gap between it and the area to be insulated. So if you install it on your van’s metal interior, you’ll need a 3/4 inch gap of air between it and the interior wall you construct. This might be a valid insulating option for you if you plan on staying in warmer areas but still want some protection from the cold.

Even though we don’t recommend using it to insulate your walls or ceiling if you need something really warm, that’s not to say that Reflectix doesn’t have its perks. It’s easy and safe to install for folks who don’t need a high R-value. It’s also perfect for making a window covers to keep the radiant heat out of your van, and it’s great for minimizing thermal bridges in your van (more on that in Part 3 below).

Foam Board

Foam board is a very popular option for insulating your van. It’s a rigid sheet of foam with an R-value of 6 per square inch! It is inexpensive, non-toxic, and pretty easy to install. The foam core itself is non-toxic and moisture-resistant, which is good for combating mold and mildew. You’ll want to look at the flame details on your board — some have a flame retardant added to the polymer mix, but if it doesn’t, it’s combustible.

We’d recommend two types of foam board: polyiso (R-6, more expensive) or extruded polystrene (R-5, also called XPS). Foam board is a popular and solid choice for insulating your van. Installation is pretty simple: cut to size, spray adhesive to the van, and stick the foam to it.

The only cons we really see in foam board is that it is flammable and can emit a high-pitched squeaking sound if it gets loose and rubs up against your van walls. We decided not to risk having a squeaky van – but we’ve met folks who have installed foam boards, haven’t had any squeaks whatsoever, and love it. Your mileage may vary!

Spray Foam

This is a great option for filling nooks and crannies of your van – and it’s also a valid choice for insulating your entire van. It has an R value of 3.7 and helps to protect your sheet metal from humidity/corrosion as it resists moisture. However, it is messy to apply, it’s not that eco/health-friendly, it’s semi-permanent (unless you like scraping), and it’s not great at deadening noise. Once cured, it is combustible and will burn if exposed to open flame or high-energy sparks. The big hurdle here is that you can really make a mess in your van if you don’t install the spray foam correctly, and if you use too much it can even deform your van’s paneling.

Thinsulate

Thinsulate is a more expensive option with an average R-value, but it’s definitely a valid installation choice. This is a fabric made by 3M to insulate winter coats, and it doesn’t absorb moisture (mold-resistant), it’s flame resistant (and passes the Federal Motor Vehicle Safety Standard Flammability Test), it’s easy to install since it’s pliable (and easy to shove in nooks & crannies), and it’s also non-toxic. The roll is about 1.5 inches thick, which equates to an R Value of 5.1 — not as high as foam board. It’s really light, has good sound insulation, and is removable. Installation just requires cutting it to shape, spraying adhesive to your wall, and sticking it.

Fiberglass

Fiberglass is the pink, cotton-candy looking (but not tasting) insulation used in a lot of houses. Even though it has an average R value (R-3.7), is non-combustible, and is cheap and easy to install, we can’t recommend it for long-term van living. It absorbs water (and mold and mildew), which can lead to corrosion and rust – and it is not friendly for your respiratory system. Some folks use it sparingly in their van doors as a cheap way to insulate. If you do use fiberglass, be sure to get it formaldehyde-free, don’t breathe it in or get it on your skin when installing it, and do your research on whether to use a vapor barrier or not.

Here’s a summary of the insulation materials we considered:

Note:
Thickness: we’re using one inch for each material with its associated R value, except Reflectix only requires 3/4 and Thinsulate is 1 1/2″.
R Value: Reflectix – some think this is exaggerated. Thinsulate: this R Value assumes it’s 1 1/2″ wide.
Cost: Nominal R-value / Unit Thickness. We gathered this from Gnomad Home – go check ’em out!

Part 3: Our Recommendation

And the insulation winners for us were:

It was difficult to make the final decision about how to insulate our van. Ultimately, we chose Thinsulate for its moisture control, good-enough R Value, and peace of mind that it wouldn’t squeak or affect our health. Foam board was a close second. Installing Thinsulate on our walls, ceiling, and nooks & crannies was pretty easy — we even had some leftovers that we used to double-up the thickness a few parts of the van. We even used it in our sliding door, above the ProMaster’s overhead compartment, and in the side-pillars by the front doors. We saw another couple that used Thinsulate to insulate their van for skiing throughout Canada during the winter — if it’s warm enough for them, we figured we’ll do great keeping warm in the States! With the help of our Webasto heater, of course.

Installing it was really easy: we cut our fabric pieces to size using a fabric scissors first. Then, we sprayed the van wall and the white side of the Thinsulate with 3M 90 Adhesive Spray, waited 30-60 seconds for it to get tacky, and stuck it to the wall. It doesn’t get much easier than that! We even used it in all the little holes and nooks in the van’s frame, and we removed the headliner above the overhead compartment to lay a nice blanket of Thinsulate over the front compartment, too.

We used EZ Cool on the metal frame of our van that we couldn’t cover in Thinsulate to combat thermal bridges. Reflectix would have worked just fine too. Installation was super easy — cut the EZ Cool to size, spray the wall with adhesive, and stick it.

We decided not to insulate our floor for three reasons. First, Thinsulate isn’t a rigid material, so it would compress and not insulate very well (if at all) beneath a heavy floor. Second, we didn’t use foam (a popular option) because Isak is 6 feet tall, and ensuring we have head space in the van is more valuable for us. And finally, since heat rises, you get the most bang for your buck insulating the ceiling the best anyways. We did cover our floor in a sound deadening material – and even if we’re unsure about how good it is as reducing road noise, it does double-work combatting a thermal bridge there. That plus 3/4” of particle board should provide some super minor insulation against the ground, but insulation nonetheless.

We’ve got a few other ways for keeping it warm if we get stranded in a cold snap: a thick rug for the floor, an insulated curtain behind the front seats, and a heavy-duty window cover (EZ Cool plus Thinsulate) for our kitchen window. We haven’t had to test these yet (thankfully), but this is our plan if we do face some serious cold weather. That plus slippers and wool sweaters should do the trick even during the Midwestern polar vortexes.

Our van is essentially a ski-mobile during the winter — not a modern, high-efficiency home featured in Architecture Digest. Since insulation is such a debated topic in the van conversion community, it can be easy to feel overwhelmed and frustrated on finding the right fit for you. If I could write a letter to my past self who was furiously researching van insulation, it would be this: we’re not looking for Aristotle’s ideal version of the ultimate, perfect van insulation — we’re looking for insulation that we can install and forget about so that we can focus on van life, not the van. Do your research on the pros and cons of different insulation materials, find one or two materials that fit your needs, install it and move on.

When Not To Insulate

If you’re planning to stay somewhere warm during the winter months and don’t plan on traveling anywhere cold, you might not need to insulate your van (or you could use something low-cost). When the summer heat comes, insulation will delay the heat from getting in – but unless you’re running some sort of AC in your van, the heat will eventually get in.

And hey, you always have the option of not insulating your van and opting for a super warm down sleeping bag instead (as long as you have the freezing-water situation figured out). We’re not here to tell you how to live your VanLife, we’re just trying to help make your van conversion easier.