Insulating your van is important due to one very basic reason: the outside environment is not always conducive to human comfort, and humans like to be comfortable. And so when we put a lot of time and effort into a project (like a van conversion), the insulation is a key component to guaranteeing that comfort in both hot and cold weather.

We go into a lot of detail on vehicle insulation in a separate article, but we’ll hit on some of the basics here. First, there is a tendency in an environment towards homeostasis. When something is hot and something else is cold, they will exchange heat until the two environments are the same temperature. We want to slow down this process, so that it’s easier to keep our preferred environment (the inside of our van) a comfortable temperature. There are 3 ways heat is transferred: conduction, convection, and radiation.

Conduction is when heat is transferred through solid materials. A good example to think of is a pan on a hot stove. In a van, most of the heat transfer due to conduction is the radiant heat from the sun heating the body of the van and then that heat transmitting inside the van.

Convection is when heat is transferred through liquids or gases. The most basic form of this is less dense hot air rising, and more dense cold air sinking. This process is always happening all around us, whether we notice it or not. For a van, the most relevant path for heat here is when your van is not well sealed. If the van has air gaps (most common around doors and windows), it will be much harder to maintain temperature.

Radiated heat is electromagnetic infrared waves. When an object is in the pathway of these ways, they heat the object. Radiant heat is why metal gets hot to the touch when it sits out in the sun. For a van, this radiant heat increases the temperature of the walls and ceiling of the van. It also comes in through the glass windows.

Remember, the goal of van insulation is to slow down these processes of heat transfer, so that it’s easier to maintain a comfortable temperature in your van. Fortunately, this is not a novel problem that hasn’t been solved before, so there are plenty of solutions out there to help you control the van’s temperature.

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STEPs to insulate a van

For this article, we are going to focus on your insulation options for the back cargo area of your van. If you’re concerned about the driver’s cockpit area, check out our article on van soundproofing where we go into detail on how to make your van comfortable to drive around. We go into detail both on the soundproofing steps you can take to improve the entire van as well as strategies to soundproof and insulate the front driver’s area. We won’t rehash all that here. Our recommended steps to insulate a van are:

1.  Add Insulation to Wall Cavities
2.  Add Additional Insulation to Wall Assembly
3.  Insulate Around Weak Points (Windows and Doors)
4.  Have a Vent Fan and Avoid Vapor Barriers

STEP 1: FILL ALL YOUR VAN WALL CAVITIES WITH A HIGH R-VALUE INSULATION MATERIAL

Because you plan to hang out and sleep in the back cargo area, you will want to prioritize insulating the entire area. The keys to effective insulation are (1) to cover as much of the inside of your van as possible with sufficient R-Value to reduce heat transfer and (2) to ensure you don’t have any air gaps. The easiest place to install insulation is every cavity between the metal ribs on the wall/ceiling. Because it’s a flat surface all the way across, you easily can install the insulation with a friction fit, a spray adhesive, or super strong acrylic tape. That hollow area is going to need to be filled if you plan to frame in actual walls. Filling this space (but don’t overstuff!) with insulation is absolutely key to reducing heat transfer AND reducing airborne sound that penetrates the wall of the van. Again, staying out of soundproofing and sound deadening in this article, but the principles involved are the same as soundproofing a wall in your house. Fill the cavity. Ensure the wall is sealed.

STEP 2: ADD AN EXTRA LAYER OF INSULATION OVER THE RIBBING! (IF YOU HAVE SPACE)

Once you’ve filled the hollow cavities, the next step depends on how you are building out your walls. If you have space, add more insulation over the top of the ribbing (still behind your new wall). This extra layer of insulation is additive to the total R-Value and creates a thermal break.. To some people that thermal break will be overkill because you either don't need it or you don't want to take up valuable square footage in a tight space. But sometimes it's the right decision. If you leave large parts of the metal exposed, heat will still have a pathway in and out as the metal ribs are attached to the outside metal (we call this a “thermal bridge”). Hijacking this pathway will help your overall van insulation, but is sometimes skipped due to constraints and other priorities (like trying to have as much space in the cargo area as possible). On the list of priorities for van insulation, we will always prioritize a van that is well sealed over covering every thermal bridge.

STEP 3: INSULATE BIGGEST SOUND AND HEAT LEAK AREAS LIKE YOUR WINDOWS AND DOORS

Ever noticed how the room in your house with all the windows tends to be the coldest in the winter? Your van will be the same way. Most of the heat transfer in your van will be through the windows. As a very wise man once said, “Mo’ windows, mo’ problems”.

The good news is that we know this is going into the van conversion, so we can plan for it. The easiest way to solve this is with thick, insulating curtains or DIY curtains made out of a true thermal insulation material. The goal is something you can open and close when desired. If the material has a reflective surface on one side, even better, as this will be helpful in the summer for keeping the sun’s heat out. Our customers often use Heat Wave Pro for this, because it’s flexible, it’s filled with recycled cotton fibers, and it’s sandwiched between reinforced, reflective foil.

Windows in doors and windows in walls should be treated the same way. The windows and doors are the most common problem areas for insulation in a van conversion. You should also check the doors for air gaps as the easy airflow to the outside makes your insulation far less effective. You can check for air gaps by listening for wind noise as you’re driving. If you're feeling extra scientific, use an infrared thermometer to see the temperature difference near these potential openings.

Step 4: Have a Vent Fan and Avoid Vapor Barriers

First, on the fan. If you want to control the temperature in your van, you need one. The fan also will be key to having proper ventilation inside the van, which removes moisture and smells from your living space. Make sure you’ve planned for an appropriate power source for your fan of choice.

Next, on whether to have a vapor barrier. We are familiar with both sides of the argument. Those in favor of a vapor barrier say that you will be generating lots of moisture while you live in the back of your van. If that moisture gets trapped behind the walls, the water could eventually cause the metal walls to rust. Also, wet insulation is useless insulation so you don’t want it getting wet behind the wall. Those against a vapor barrier say that sealing off the moisture is what creates the danger in the first place, because a well-ventilated van allows the moisture to dry and escape.

The short version is that those against the vapor barrier are right in “almost” every situation. The primary reason is that condensation forms on metal when warm air cools. In a hot, humid environment, the metal walls and roof of your van are going to sweat. Earlier we talked about part of #vanlife is traveling all over. You’re going to run into humidity and rapid temperature change.

You can also just avoid the whole problem by using our Spectrum Liquid Deadener as your vibration damping material, as it is waterproof and rustproof in addition to being awesome at stopping structural vibrations and noise.

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There’s a huge variety of materials available to use as insulation in your van. We’ve consolidated the best specialty materials you can use, and ship them out every day from our warehouse. There’s also stuff you can get at Home Depot, which we don’t bother to carry because we’re not going to beat Home Depot at being Home Depot. Check out the table below for a quick product comparison:

• • Mega Zorbe – Our 1/2" hydrophobic melamine foam is our best insulator and sound absorber. It’s flexible, Class A fire rated, highly absorptive of sound, and water flecks right off of it. It’s a premium option that comes with an easy peel and stick backer if desired. The ½” version of Mega Zorbe is most often used on the ceiling when someone wants premium, easy to install, and to preserve headspace.
  • Mega Zorbe Pro – It’s the same hydrophobic melamine foam, but it comes in 1” or 2” thick panel options. Mega Zorbe Pro is most commonly used on the walls.
  • CelluZorbe – Made of recycled cellulose fibers, this sound and thermal insulation is the most cost-effective fibrous option. We offer it in 1” and 2” thicknesses, and it’s the “go to” for someone who’s looking for ecofriendly and budget friendly.
  • EcoVerb Roll – The bonded acoustical cotton has a black liner material and comes in a giant roll. It’s a cousin of the Ultratouch Insulation that was discontinued back in 2020. We warehouse these rolls in ½”, 1”, and 2” varieties.
  • Heat Wave Pro – This cost-effective, and high R-Value jute material is extremely flexible and sandwiched between two layers of reinforced foil. It’s most commonly used as DIY window curtains or as a thin material to create a thermal break.
  • Luxury Liner Pro – We’ve fused mass loaded vinyl to closed cell foam to create our best automotive noise barrier. For those concerned about road and tire noise, install this barrier with 100% coverage on the floor and over the tops of the wheel wells. The high R-Value and excellent noise blocking make it perfect for your van floor insulation and soundproofing.

Vans are incredibly versatile, and we love to see what our customers are able to do with them, both professionally and personally. We’re here to help you with your passion, and make sure your time in your van is as comfortable as home.

If you'd like to see all of our materials, check out our guide on car insulation as well as our breakdown on the cost to insulate a van. We also have a Sprinter Van insulation kit that outlines exact materials needed based on the type of van you have.

Feel free to contact us and we can help you find the right materials to finish your project. And when you’ve completed your project, send us pics and helpful tips so we can continue improving our guides! Van insulation projects are one of our favorites to share with the Second Skin community.