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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 you Need Insulation in Your DIY Van build
Insulation should be the first step when building out your DIY 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.
Types of Heat Transfer or What you should know about insulation
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.
Things to look for in vanlife insulation:
- Water Resistance
- Whether it’s toxic
- Application – is it easy to apply? Do you need a professional?
- Price – Does the price make sense for the value?
7 types of vanlife insulation
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. Foam Board
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 is another great vanlife insulation choice for your campervan. We personally use the Owens Corning Foamular 2 in for our ceiling. It is fairly easy to install but 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 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
3. 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
4. 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
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.
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
The Method We Chose for our 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).
Insulating Your Windows
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 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.
If they are out of your budget then use these instructions on how to make DIY window covers.
Instructions for DIY window covers:
- Buy a roll of reflectix
- Use cardboard to use as a template for your window cutout. Make sure you cut the template to the metal around your window, not just the window itself. You will need the reflectix to hit the metal surrounding the window so magnets can adhere and keep the window shade in place.
- Once window cutouts have been established, place the template on reflectix to trace out the design then cut the template. We chose to cut it a little bit bigger and trim off excess as needed.
- We used rare earth or neodymium magnets and taped them on reflectix with magnetic/thermal tape.
- If you have a sewing machine you can then add fabric.
Vanlife insulation FAQ’s
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.