Camper Van Insulation 101

If you’re just starting out on your DIY van build journey, installing insulation should be at the top of your checklist. 

For one thing, campervan insulation must be installed behind your wall and floor panels, so it should be planned early. In addition, van insulation is an aspect of your build that has a massive impact on your overall comfort levels. Therefore, it shouldn't be overlooked.

When you insulate your Sprinter or Transit van well, it serves two essential functions. It keeps your van comfortable regardless of the season, and it helps reduces noise. 

In this post, we’ll go over the main reasons why insulation is important and recommend some of our favorite products.

Why should you insulate your Camper Van?

Sprinter Van - Winter Insulation

Whether you’re starting out with a new bare shell or converting a used Sprinter or Transit van into your dream camper van, it’s unlikely that you’ll be able to adventure comfortably in it straight away. Without the proper amount of camper van insulation, you’ll be freezing during winter ski trips or feel like you’re in a mobile sauna during hot summer days. 

With insulation, you can comfortably ride out temperature changes. It creates a barrier that slows down the heat transfer rate between the inside and outside of your van. Basically, this helps you maintain a steady temperature for longer so that you can enjoy the living space inside the van you worked so hard to build. 

Here are some of the main reasons why you should take van insulation seriously:

  • A well-insulated van gives you usability during all four seasons, regardless of the climate. 
  • Good insulation is moisture-resistant, which prolongs your van’s life and provides a healthier indoor environment.
  • Proper insulation helps you save on energy from excessive heating and cooling.
  • Insulation reduces noise from entering or exiting the van. It’s excellent for dampening road vibrations as well as keeping your campsite neighbors happy when you’re rocking out to music late into the night. 
  • It can reduce the chances of insects or animals that might try to enter through holes, cracks, or gaps in your floors and walls. 

R-value - What is it, and why does it matter?

R-value is a measure of the thermal resistance of a material or assembly of materials. Practically speaking, a higher R-value per inch indicates greater insulating power.

Why is this important? Because when trying to keep your van warm during the winter, or, cool during the summer you’re dealing with three types of heat transfer: conduction, convection, and radiation. 

  • Conduction is when heat gets transferred through a material, like how the metal surface of your van gets hot in the sun and heats up the interior. The less dense a material is (insulation), the less it will conduct heat. 
  • Convection is the transfer of heat through liquid or gas – such as the air inside your van. When you turn on your MaxxAir fan, you’re using convection to cool the air. For heating, insulation helps by getting rid of air gaps that can suck away warmth from the inside of your van. 
  • Radiation transfers heat through electromagnetic waves. For example, when the sun streams through your van windows, it transmits radiation heat. You can prevent this by covering up your windows with insulated window covers that reflect radiation.

R-value ratings take these different types of heat transfer into consideration, and they can help you make the best choice when it comes to picking the correct kind of insulation for your van build.

R-values can range from R1 to R10. A material with a high R-value per inch, such as yellow spray foam (R-6.5), will insulate better than a material with a low R-value per inch, such as fiberglass (R-3.5). 

However, R-values shouldn’t have the final say regarding the insulation you choose for your van. Instead, there are multiple factors to consider, such as budget, ease of installation, moisture resistance, flexibility, and more, that should influence your final decision. 

Make sure to know your priorities and research how the different insulation types have affected van life or camping for other people in the past.

Sound Dampening - Yes, you need it!

Before we dive straight into the insulation, let's go over sound dampening. We highly recommend investing in sound deadening and it's a project you'll tackle before insulation, so it's important we noted that here. 

Sound dampening materials are a must for those who want to reduce the noise and vibration from outside your van. Sprinter, Transit, and Promaster vans are cargo vans at heart, so they aren't designed to prevent road noise like a typical car or truck and thus require a little more work upfront, but it's worth it. 

Be sure to focus on the wheel wells, walls, ceiling, and the doors. Typically, 50 square feet is enough to make a major improvement in noise and vibrations in most camper vans, and you can add more if you are looking for an even better result. 

Peel and stick sound deadening is the most popular option for van conversions and these are a few brands & products we recommend. 

Kilmat Automotive Sound Deadener

Hushmat Sound Deadener

FatMat Self-Adhesive Rattletrap Sound Deadener

Common Van Conversion Insulation Materials

There are many insulating materials available for converting your van. The most common insulators are 3M Thinsulate, Havelock Wool, Polystyrene, Reflectix, Extruded Polystyrene (XPS), and Expanded Polystyrene (EPS).

If you’re on a tight budget, you may be tempted to use whatever you can find lying around or come up with other DIY solutions. However, it’s best to use proper insulation materials. Not only will they regulate the temperature more efficiently, but they’ll also hold up better against moisture, mold, and wear and tear. 

Below you’ll find some of the most common insulation materials that are used for van insulation. 

3M Thinsulate (R-value of 5.2) 

3M Thinsulate is an incredibly effective, 3-layer insulating material that is popular for insulating vehicles. While it doesn’t have the highest R-value compared to other insulating materials, it’s a premium choice that can be used to insulate many areas such as flooring, roofs, and walls. 

Best features:

  • It's Hydrophobic which means it doesn’t absorb or trap moisture.
  • Non-toxic – good for a healthy indoor environment.
  • Good sound-proofing properties.
  • Easy to install with spray adhesive.
  • Handy for stuffing into nooks and crannies.

Take note:

  • Expensive compared to other some of the other insulation materials.
  • Slightly lower R-value means you might need to use more material.

Havelock Wool (R-value of 3.6 - 4.3)  

Havelock Wool is a great insulator because it is made of natural fibers that have excellent moisture-repellant properties. In addition, because Havelock Wool is 100% natural sheep wool, it’s environmentally friendly and good for your health. 

Best features:

  • Non-toxic, environmentally friendly, and safe for your health.
  • Natural breathability and moisture control that resists mold and mildew.
  • Relatively low price if you have a supplier nearby.
  • Some sound-proofing properties.

Take note:

  • Less common and can be expensive to order if no suppliers are around.
  • Lower R-value means you’ll have to use a thicker layer than other options, which could eat up extra space.

Spray Foam (R-value of 6-7) 

Camper vans are full of hard-to-reach areas that can make it tricky to add rigid insulation boards. Spray foam has excellent insulating properties and can be the perfect solution for filling the many gaps and holes in your van’s metal frame. However, be sure to apply it correctly – you may even want to enlist the help of a professional. It can be tough to remove once it’s applied, and it's not exactly a DIY-friendly material to work with.

Best features:

  • A high R-value makes it a great choice for regulating temperature. 
  • Water-resistant.
  • Some sound-proofing properties.
  • Great for filling small gaps, so you can use it in addition to other insulating materials.

Take note:

  • It can be very tricky to install correctly. Take extra care to not overdo it, or your paneling will not be flush.
  • If you make a mistake, it can be costly and difficult to remove. Some body shops may refuse to take on the job.

Reflectix (R-value of 1-4)

Reflectix camper van insulation is made of two flexible reflective layers of air trapped between aluminum foil. This makes it an excellent insulator because it can reflect radiant heat, as well as reduce thermal conductivity and convective currents within the van. However, it’s best used as a window reflector rather than full-scale insulation. Since it requires an air gap to be effective, it doesn’t have good convection or conduction insulation properties. 

Best features:

  • Excellent as a radiant barrier.
  • Light and easy to work with.

Take note:

  • Insulation properties are not effective when placed against other materials.
  • It can be prone to tearing.

XPS Rigid Board (R-value of 5)

Extruded polystyrene (XPS) is one of the most popular insulation materials. It’s readily available and is an affordable choice that provides good insulation properties. It doesn’t absorb moisture, but it can create air gaps when placed over uneven surfaces due to its rigid shape. 

Best features:

  • Good insulation properties.
  • Affordable and readily available at most hardware stores.
  • High compressive strength makes it a great choice for flooring insulation.
  • Performs better than polyiso in extremely cold weather.

Take note:

  • Not environmentally-friendly.
  • Not convenient to use for nooks and crannies.

Our Favorite Options for Camper Van Insulation

We believe these insulators are the best options for insulating your camper van. They insulate well and have the best mix of performance and ease of installation.

3M Thinsulate Insulation 

3M Thinsulate Insulation

Each insulation material has its pros and cons, but we consider 3M Thinsulate the all-around winner. After all, it’s what we personally use to insulate our marketing vans. 

We find that 3M Thinsulate is the easiest to work with. Unlike other options that require a lot of measuring and adjusting to size, Thinsulate can simply be applied with spray adhesive. All you have to do is spray the target area, wait 30-60 seconds, then press the Thinsulate firmly against the surface. If you make a mistake, it’s much easier to remove and fix than other options like insulation boards or spray foam.

Thinsulate has excellent moisture management characteristics. It doesn’t absorb moisture and allows water vapor to pass through it, so you never have to worry about mold or mildew. 

It’s also non-toxic. This is a great benefit, considering how other materials like fiberglass insulation can shed harmful fibers, and insulation boards are produced with questionable chemicals. 

An added benefit to Thinsulate is its sound-absorbing properties. With other insulating materials, you may have to install a noise barrier as well. 

While it doesn’t have the highest R-value, we find that Thinsulate offers the best qualities compared to its competition. It’s a breeze to install. Any leftover material can easily be stuffed into empty pockets of space to provide extra insulation. 

It isn’t available everywhere, so you may need to buy it directly from the 3M website. It costs a little more than other materials, but we think it’s definitely worth the investment.

Havelock Wool Insulation

Havelock Wool Insulation

If environmental impact is high on your priority list, look no further than Havelock wool insulation. It’s 100% natural sheep wool and offers some excellent all-around insulating qualities. 

While it’s not technically hydrophobic, it still does an excellent job of managing moisture and condensation inside your van. As a result, many van dwellers swear by the stuff and appreciate its natural breathability properties that prevent mold and mildew.

Havelock wool insulation is easy to install, just like Thinsulate. Since you’re not dealing with bulky, rigid boards or messy spray foam, you can adjust your work as you go without worrying about making a huge mistake that requires you to start over from the beginning.

Since it’s a natural fiber, it doesn’t have the highest R-value, coming in at around R-3 to R-4. However, since you’re realizing the benefits in terms of health, ease of use, and overall insulation properties, it’s another pick that you can’t go wrong with. Of course, you’re doing your part for the environment as well. 

Insulating your windows with van window covers

Last but certainly not least, window covers are an important step to finalizing the insulation process in your van. 

Without window covers, all the excellent work you did installing insulation throughout the rest of the van will be compromised. In winter, cold air will seep through the windows and cause the inside temperature to drop rapidly. During summers, powerful radiant heat from the sun will stream through the windows and force you to spend the day outside your van. 

Window covers are a simple way to ensure that your van interior is as comfortable as it can be.

Final thoughts

While it may be easiest for your workflow to stick to one type of insulating material, you might also consider mixing and matching according to the areas of the van that need insulating. 

For example, you could use XPS foam board for the floor due to its high compressive strength. 3M Thinsulate or Havelock wool is great for the walls and ceiling because they can fill in all the uneven spaces created by your van’s metal frame.

Now that you know how to insulate your camper van and what the best insulation materials are, it's time for you to choose from one of our favorite options above and insulate your vehicle. After all, a more comfortable van means more adventures!


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