Imagine this….it’s your first morning in your van. You wake up to an epic mountain view out of the back of your campervan. You’re so ecstatic to have finally finished your build and to be out on the road. One problem – it’s absolutely freezing! You were not prepared for how utterly cold it was going to be! You take a step out of bed to make your morning coffee and your floor feels like an ice skating rink! In the rush to get your van built, you skimped on the vanlife insulation or maybe you didn’t put any in at all. Don’t ruin your experience by missing this important step.

After building out our Sprinter van by ourselves we have learned so much about the things we did right and the things we definitely could have improved on. This is why I am creating a vanlife insulation guide for you, so you can learn from us! 

Don’t make the mistake of skimping on insulation and regretting it, after there is nothing you can do! This vanlife insulation guide will help you learn about thermal insulation, the insulation types, and our recommendations for your van build! Read on to learn all the best vanlife insulation options for your DIY van build.

Why Your Van Needs Insulation

Insulation should be the first step when building out your van build. It is the foundation of your campervan and it should be thought through. There are several vanlife insulation options available and different methods for applying and installing them. The important thing is that you begin thinking about your budget and your skill level for applying insulation. We definitely do not recommend skimping on your insulation no matter what you will be using your van for! 

Insulation inside of your DIY van build is important no matter what climate you are heading towards. Whether you will be in the heat or the cold, insulation can protect you from both. It keeps the cold out when it’s freezing and it keeps the heat out when you’re in the desert. Insulation is a step in your van conversion you MUST not skip as even in the warmer places it still gets cold at night. You will appreciate the time you took to insulate so that you aren’t freezing. It can be a tedious and time-consuming step when you are ready to dive in on the fun part of the build but vanlife insulation can be quick and easy if you do it correctly. 

R-Value & Vanlife Insulation

When considering what insulation to use in your campervan one component to consider is how well it will insulate your van for the amount to insulation you use. The way insulation effectiveness is measured is called R-Value.

WHAT is R-Value

R-Value is a term used to measure a specific material’s thermal resistance meaning its ability to resist heat transfer through conduction. When looking at R-Value, the higher the number the better. Typically R-value is measured per inch of material. For a more thorough explanation of R-Value use this guide.

What to Look for with Vanlife Insulation

  1. R-Value 
  2. Water Resistance
  3. Whether it’s toxic
  4. Application – is it easy to apply? Do you need a professional? 
  5. Price – Does the price make sense for the value?

8 Types of Vanlife Insulation

There are many vanlife insulation types and they are not made equal. From insulating on a budget to hiring a professional to spray foam your van, you have to consider what is best for you and your van. Read on to learn the different types of insulation below.

1. Spray Foam Insulation 

If Shawn and I ever build another van we will likely pay for a spray foam insulation kit. They cost more money but are super effective at insulating the van and covering up all the different parts of the van that other insulation choices can miss. You can order your own DIY kit or pay for it to be done. The downside is that using a spray kit can be more difficult and easy to mess up. You not only have to spray the insulation but you need then trim the expanded foam so it is flat and walls can be properly installed. If you do it yourself make sure you follow all the instructions.

R-Value: 6-7 per inch 

Pros: High R-Value, covers everything in one swoop, no need to worry about crevices

Cons: Pricey (around $600 for a kit), can be difficult to get walls flat after installing, a little more difficult for a novice to do themselves

2-4. Foam Board

There are three primary types of foam board insulation you can use in your van that are readily available and sold at your local Lowe’s or hardware store.

Polyisocyanurate (polyiso) RECOMMENDED

Polyiso is always a popular choice in the vanlife community as it is reliable, fairly inexpensive, and does a good job of insulating the van. Shawn and I did, however, have difficulty locating a 1-inch board which is the best option. Depending on where you live you may also run into this issue. If you find you can’t locate a 1-inch polyiso board then we recommend moving to polystyrene. 

R-Value: Can range but around 6 R-Value per inch 

Pros: Fairly inexpensive, easy to find, easy to install, highest R-Value for foam insulation

Cons: Rigid and cannot fit into small crevices

Extruded Polystyrene 

Extruded polystyrene is another great vanlife insulation choice for your campervan. We personally use the Owens Corning Foamular 2 in for our campervan subfloor. It is fairly easy to install but if you install it on the walls or ceiling you will need to have spray glue and patience as it can easily fall off. You also have to do quite a bit of cutting and trying to fit your foam into the odd shapes in your campervan. 

R-Value: Around 5 R-Value per inch 

Pros: Good R-Value, Lower price, R-value retention even in heat or cold, fairly easy to install

Cons: Rigid and cannot fit into small crevices

Expanded Polystyrene (Not Recommended)

Expanded polystyrene is a cheaper option for your vanlife insulation. It is a rigid foam board that is the cheapest insulation option but has the lowest R-Value. It also has the possibility to hold moisture which means it wouldn’t be great for your campervan since it won’t likely be sealed. 

Pros: Low price, easy to install

Cons: holds moisture, rigid and cannot fit into small crevices

5. Canned Spray Foam 

Canned spray insulation is great for the nooks and crannies of your van. Inside the doors, in the small nooks that large pieces of polyiso cannot fit into. We used this in conjunction with foam board. The foam board doesn’t fit perfectly into the wall so you can utilize canned spray foam for the areas where the board won’t fit. 

R-Value: 3.7 per inch

Pros: great for small crack and crevices

Cons: Not a solution for the entire build 

6. 3M Thinsulate

Thinsulate is a synthetic fiber thermal insulation that is a down-free alternative that you will often see in brand name outdoor gear jackets. Its claim is that it is less bulky and warmer than down and you don’t have to use animal products. It is also available in large quantities used for insulation of campervans and for sound dampening. 

3M Thinsulate is a popular choice in van builds. It’s flame-resistant, doesn’t mold, is non-toxic, and is a sound dampener. The issue is that it is pretty pricey, has a lower R-Value and insulates your entire van. It would take around 180 feet of Thinsulate which will run you about $500. However, it is a great choice if you are willing to pay the price. 

Personally we used the Thinsulate for the roof of our cab and in the cracks and crevices of the rest of the van. 

R-Value: 3.3 per inch

Pros: Easy to install, sound dampener, easy to fill all cracks and crevices

Cons: Expensive 

7. Denim

Denim batting is an eco-friendly vanlife insulation product. It is used from recycled denim clothing and can be easily purchased at your local hardware store. Unfortunately, the benefits do not outweigh the disadvantages when using it for your DIY van build. Denim holds moisture and therefore can mold which is a definite no-no when living in a small space that isn’t sealed. Not to mention it needs a vapor barrier to properly insulate which is another step.

R-Value: 3.5 per inch 

Pros: Eco-friendly, easy to install, great for cracks and crevices, toxic-free

Cons: Requires a vapor barrier, more expensive option, retains moisture and can mold. 

8. Fiberglass 

Honestly, I didn’t even want to list fiberglass as an option. However, it TECHNICALLY is an option and I want you to be informed. Fiberglass is toxic, shouldn’t be breathed in and honestly isn’t that great at insulating. We definitely DO NOT recommend using fiberglass to insulate your van. 

Pros: Honestly I don’t know any for a van build 

Cons: It’s fiberglass, it’s toxic, has a low R-value, and is expensive. Since campervans are not fully sealed fiberglass can escape causing breathing issues.

How to install vanlife insulation

Now that you have picked out your insulation type, it’s time to install it. If you are going to do spray insulation yourself, I recommend watching a tutorial on Youtube as it is easy to warp your van metal if you don’t know what you are doing. Otherwise below is the method we did for our Sprinter van which covers the other insulation methods.

The Method We Chose for our First Vanlife Insulation

Walls: Rattletrap, 1-inch polyiso with spray glue, spray foam to fill the gaps, and 3M Thinsulate in other gaps

Ceiling: 2 In extruded polystyrene, Thinsulate in gaps

Floor: ½ polyiso, thermal tape with the stock subfloor

Front Cab: 3M Thinsulate, 1 in polyiso with spray glue on the interior roof 

For our insulation, we chose to use polyiso, spray foam, and Thinsulate. We also used rattletrap as a sound dampener. Rattletrap is used in luxury vehicles for sound dampening and also used in stereo competition vehicles as it absorbs vibrations from the road noise. Have you ever been in a Lexus and noticed how quiet it is compared to its non-luxury counterpart “Toyota”, or noticed the difference in road noise? Part of that is due to the use of a sound dampener such as rattletrap. A bonus is that it has a small R-value meaning it helps insulate as well as reduce noise.

We used 1-inch Polyiso board from Lowe’s and cut it up to fit into the walls and ceiling. To keep the board up you will need to use spray glue. It’s not an easy process and you might end up finding that the insulation falls easily. Use trial and error and find ways to hold up the insulation while it dries overnight. We supplemented spray foam for the ridges in the walls and ceiling. For the floor, we used ½  in polyiso taped together with thermal tape in conjunction with the stock subfloor. 

What is the best insulation for a camper van?

The best insulation for a campervan in our opinion is foam spray insulation which can be done yourself with a DIY kit. The most used insulation is polyiso boards combined with canned spray foam. 

If you don’t want to use a spray kit this is the recommended insulation by section 

Walls: 1-inch polyiso foam board, foam spray for cracks and 3M Thinsulate for crevices

Ceiling: 2-inch extruded polystyrene, Thinsulate in gaps

Floor: Frame out flooring with 1-inch Polyiso and seal seams with thermal tape

Front Cab: Insulate your interior roof with 3M Thinsulate and 1-inch polyiso with spray glue.

Back and Side Doors: Insulate your doors with rattle trap and 3M Thinsulate (we don’t recommend insulating the front doors as you could affect your wiring). 

Keeping heat in or out is much easier if you have a way to insulate your windows. That is why having window covers is super important for your vanlife insulation. There are plenty of options that are available for your specific van model or you can always make them yourself. 

We chose to make our window covers ourselves in the beginning when purchasing them wasn’t an option. DIY window covers will absolutely do the job; however, purchasing professional ones will likely insulate your windows better, store much easier and you don’t have to worry about figuring how to cover them in fabric, which was a big hurdle for us. 

We personally recommend Wanderful Window Covers as they are a small business (we love supporting small businesses). They are also the most reasonably priced window covers we have seen and we love how easily they fold up accordion-style when not in use. 

If they are out of your budget then use these instructions on how to make DIY window covers. 

What is the Best Insulation for Vanlife & Other FAQs

What is the Best Vanlife Insulation?

The best vanlife insulation in our opinion is spray insulation done by a professional. It allows for all of the crevices of the van to be filled and will keep you warm in the winter and cool in the summer.

How do you insulate a van for winter?

If you plan on being in a cold area for the winter we recommend taking your insulation to the next level. Doing things such as adding Thinsulate insulation to the front cabin ceiling and filling in the door panels with Thinsulate as well. Any crevice in your van needs to be filled as air can easily slip through and make your van both damp and cold.

Should I insulate the floor of my van?

We believe yes, you should insulate the floor of your van. Even in the desert the floor of your van is going to be pretty cold and having a layer of insulation there helps to keep you warm. Honestly, no one wants to wake up and have to immediately step on a cold floor. 

Should I Insulate the Windows of my Van?

Yes, you should absolutely insulate the windows in your van with van window covers. Window covers will help to drastically keep your van cool when the sun is shining in and also keeps the cold weather out when you are trying to stay warm.

We personally recommend Van Made Gear as they are a small business (we love supporting small businesses). They are also the most reasonably priced window covers we have seen and we love how easily they fold up accordion-style when not in use. 



No mention of wool or reflectix?


Hey Rachel, I’m not the biggest fan of reflectix and have it seen so many times installed improperly that I didn’t even want to mention it. I am still researching wool but you are likely correct and I should add both of them to the list. Thanks for the reminder!


This is really and amazing idea to make Van insulating. Great reading for me. Thank you for sharing it.


All I see or find are articles for newer splinter van.
What about older Van’s? I have an 89 ford econoline e150.
What insulation and how would be recommended.


Hey Mike! My insulation recommendations are still the same. If it were me, I would use a mixture of XPS for the floor and thinsulate for the walls.


That’s really great tips. Thanks for sharing.

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