Campervan Insulation – Understanding Materials and Sound
Whether you’re building your very first campervan or your fifth, insulation is always a hot topic (no pun intended). It’s the eternal question among DIY van converters: What’s the best solution? Everyone has an opinion, and every method comes with a long list of pros and cons.
Unfortunately, there are a lot of self-proclaimed experts out there. We’ve seen plenty of claims that lack substance or are based on half-truths where the facts have been twisted a bit. Unlike housebuilding, there is no official standard for how to insulate a campervan. That makes this one of the more complex subjects to write about.
So, everything you’re about to read is based on our own experience and knowledge. On top of having a qualified building engineer in the team and several DIY campervan builds behind us, we’ve also studied how factory-built motorhomes and panel vans are insulated. Our hope is that this guide gives you a solid overall understanding of different insulation materials so you can decide what suits your campervan conversion best.
We’ll guide you through each step and material choice so you can learn from our mistakes and reflections. To keep things simple, we’ve split everything into natural sections so you can easily follow along. By the end, you’ll be a proper campervan insulation nerd.
And remember: insulating a campervan isn’t just about keeping the heat in on cold winter nights – it’s also about keeping the heat out on hot summer days.
Insulation Is About More Than Just Keeping the Cold Out
1. What is insulation and why does it matter all year round?
If you think insulation only matters when it’s below zero outside, think again. When you convert a panel van into a campervan, insulation is about creating a stable indoor climate – whether it’s scorching hot in July or freezing in December.
Insulation doesn’t just keep you warm when it’s cold; it also helps keep unwanted heat out when it’s hot.
2. Bulk insulation and radiant insulation – what’s the difference?
So how does insulation actually work? We often talk about “heat”, but heat is really just energy moving around and it loves travelling in and out of your campervan in different ways.
There are three main ways heat is transferred:
- Conduction (heat transfer through materials)
- Convection (heat carried by air or fluid movement)
- Radiation (heat transfer via electromagnetic waves)
All three can cause problems for your campervan, in every season – so it’s worth understanding them properly.
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3. What are thermal bridges?
We also need to talk about one of the most common problems when it comes to insulation in a campervan: thermal bridges.
Thermal bridges are parts of your van that act like heat motorways, where heat (or cold) is quickly transferred from the outside to the inside through conductive materials. In other words, it’s where the heat creeps through your walls.
Typical thermal bridges in a van are metal components: bodywork, ribs, beams, brackets, screws and fixings that go straight through your insulation.
4. Soundproof properly
Have you ever been woken up by unexpected street noise outside or the engine noise echoing through the van? Learn the difference between direct and indirect soundproofing and how to make your campervan feel private and peaceful – no matter where you park.
The right campervan insulation makes it possible to keep a comfortable temperature whether you’re in blazing heat or bitter cold. A common misconception is that insulation only matters in winter. In reality, good insulation is crucial both for keeping heat in during colder months and for staying cool in summer.
This guide won’t just help you choose the right insulation materials for your campervan – it will also help you understand how insulation works, which weak spots to avoid, and the lessons we’ve learned from our own DIY campervan projects.
After building several campervans, we’ve landed on a specific insulation strategy that we think works best. Read on to understand why we use this combination – and what extra factors you should consider.
Understanding the basics of insulation
Convection – Warm air loves to escape upwards
Convection is all about how air moves. You’ve probably noticed warm air rising above a radiator, or how cold water sinks to the bottom of a lake. The same thing happens inside your vehicle’s ventilation system – heat moves with the airflow.
Warm air rises and cold air sinks, and if you haven’t insulated properly you’ll literally see your heat drifting out through the roof. In your campervan, you want to block and control these air movements as much as possible.
How does it work?
Convection happens when heat is “transported” from one part of a liquid or gas to another because the warmer material rises and the cooler material sinks. A classic example is a hob heating a pot of water.
Insulating for convection:
To minimise heat loss caused by convection, it’s important to eliminate air gaps and insulate hollow sections such as frames and cavities. This reduces air circulation and therefore heat loss.
Radiant heat – the sun is not always your friend
Radiation is when heat is transferred by electromagnetic waves – the kind of heat you feel when the sun shines on your van. In summer, you want to avoid your campervan turning into an oven, and in winter you don’t want the little heat you’ve created to simply radiate out through the walls. That’s why you need protection against radiant heat, for example with reflective materials.
Hur fungerar det?
Att stå runt ett lägereld är ett utmärkt exemHow does it work?
Standing around a campfire is a perfect example of radiant heat. The air around you can be icy cold, but you can still feel the heat travelling directly from the fire to your body.
Insulating for radiation:
White or shiny surfaces absorb and emit heat poorly, which makes them good barriers against radiant heat. Use materials that can reflect heat (like foil) or light colours. A clean, white, glossy van will reflect more sunlight than a dusty black one.
The difference between mass insulation and radiant insulation
Mass insulation – your “fluffy” friend
Mass insulation is the type you’re probably most familiar with – things like wool or foam. It works by trapping air and slowing down heat transfer, which makes it effective against both conduction and convection. Think of it as a duvet for your campervan – the “fluffier” it is (to a certain point), the better it insulates.
Radiant insulation – the reflective shield
The second type is radiant insulation, which reflects heat instead of absorbing it. A common example is foil-based products that reflect the sun’s radiant heat and help prevent your van turning into an oven in summer. This also works in reverse in winter – by reflecting heat back into the living space instead of letting it radiate out through the walls.
Thermal bridges – Your worst enemy
When we talk about heat transfer, we have to mention a phenomenon that can undermine all your hard insulation work: thermal bridges. A thermal bridge appears when there’s a continuous path for heat to conduct through, allowing heat (or cold) to travel quickly from outside to inside through a conductive material.
In a campervan this usually means metal parts – the bodywork, ribs, studs, brackets and any screws or fixings that go straight through your insulation layer.
For example: you might have insulated the walls of your van perfectly, but forgotten to deal with a metal support beam. That beam then acts as a heat conductor, creating a cold surface (or a hot surface in summer), because heat can flow freely through it.
To combat this, it’s smart to use materials that interrupt this heat path – what we call a thermal break. Examples include spraying on a ceramic insulation coating such as LizardSkin, or using closed-cell materials like Armaflex on the bodywork to block heat flow.
What is heat transfer and why should you care?
There are three main ways heat is transferred: conduction, convection and radiation. All of these can either let unwanted heat into your campervan (imagine blazing sun in a field) or let valuable heat escape during a cold night. Let’s look a bit closer at these concepts.
Heat transfer – The nemesis of metal and thin bodywork
Heat transfer by conduction is probably the most familiar type and a real villain in campervans. This is when heat moves directly through a solid material – like metal.
A classic example: holding a hot saucepan handle or a spoon in a mug of hot tea. The heat spreads along the metal and reaches your fingers. Or think about how the metal bodywork of your van becomes baking hot inside the cargo area on a sunny day.
When your van’s bodywork heats up in the sun, or cools right down in winter, that heat or cold is transferred directly into the interior. Metal is an excellent conductor of heat – which we love when we’re boiling water for coffee, but hate when we’re trying to keep an even temperature inside the van. That’s why you need insulation that forms a proper barrier between the metal skin and the interior of your campervan.
Condensation and moisture control: vapour barrier or not?
The purpose of a vapour barrier is to prevent moist air from inside the van from reaching cold surfaces. Moisture comes from breathing, cooking or drying wet clothes. If this moist air reaches cold surfaces, condensation can form – which is exactly what we want to avoid.
But if the moist air somehow manages to get past the vapour barrier, it becomes difficult to get rid of it because it ends up trapped between two barriers (remember that metal also acts as a vapour barrier).
Even if you managed to create a perfect vapour barrier (which is very difficult in a van), there would still be ways for damp outdoor air to enter. There are always potential leakage points.
Why we choose to let our insulation layers “breathe” and not use a vapour barrier
Moisture and condensation is a complex topic, and there’s a lot more to say about it. Hopefully this section helps you understand the phenomenon a bit better and make a more informed decision about how you insulate your campervan.
Soundproofing – First step towards a quieter campervan
When people talk about insulating a campervan, most think about temperature control. But there’s another important part: sound insulation. No one wants to wake up at 5am from heavy traffic noise or the wind howling around the bodywork. Good soundproofing can be the difference between a night of solid sleep and a night of frustration.
But how does soundproofing actually work, and which methods can you use to keep things calm and quiet inside your van? Let’s find out.
Direct and indirect soundproofing – What’s the difference?
Direct soundproofing is about blocking sound from entering or leaving through the walls, roof or floor of the van. This type of soundproofing acts as a barrier that absorbs and stops sound waves. You can think of it like a solid front door in a house – the thicker and denser it is, the harder it is for sound to pass through.
Indirect soundproofing, on the other hand, is about damping and controlling sound that already exists inside your campervan by reducing resonance and vibrations. This might mean stopping the floor from buzzing when you drive over rough surfaces, or reducing noise from the engine, tyres and road.
How sound travels
To soundproof your campervan effectively, it helps to understand how sound works. Sound is simply vibrations in the air that travel as waves. When those sound waves hit something – like the metal walls of your van – the material starts to vibrate, which creates sound inside. Thin, hard surfaces like sheet metal are especially poor at stopping noise, because they vibrate easily and let lots of sound through.
By covering these surfaces with sound-absorbing materials, you can reduce vibrations and keep noise levels down.
Damping materials – Stopping the vibrations
To reduce indirect noise from vibrations, damping materials such as Dynamat or Noico are popular choices. These are self-adhesive sheets that you apply directly to the metal panels in the walls, roof and floor. They work by making the metal stiffer and harder to get vibrating, which significantly reduces noise. These materials are often used in car audio and motorsport to reduce noise and resonance and they work brilliantly in a campervan too.
Personally, I’ve experimented with several bitumen-based options – everything from different Biltema products (a Scandinavian budget brand) to BRL Silent Coat Vibrodamping. As with many other things, you’ll find varying recommendations – from covering 25% of the surface up to 100%.
How we installed damping mats
Because you quickly end up with large areas to cover, we chose the following approach:
- Visually divide the van into sections based on the frame and ribs. It’s mainly the large flat panels that create vibrations and noise. Ask a friend to knock on the outside while you sit inside and listen for which panels ring and need stiffening up.
- Clean the surfaces. Then cover around 25% of each section with damping mat. It helps to use a heat gun and really work the mat in for optimal adhesion. Remember: it’s mainly the large flat metal “windows” between the ribs that need stabilising – the structural parts like ribs and beams are usually already fairly stiff.
- Do the knock test again. Knock and add more where needed. This made a huge difference for us, especially after we opened up the bulkhead behind the seats. If you’re planning long drives with a fully or partly open bulkhead, this step is almost a must.
- If your van is older and the panels drum a lot on the motorway, a bead of sealant or adhesive between the ribs and the large metal panels can also help a lot.
Bonus tip: don’t be too eager – wait until the weather is a bit warmer or use a decent heat gun! The first time we were so keen to start the conversion that we ignored the cold. Even though we used the heat gun constantly, the job took much longer than it would have if we’d just waited for spring.
Materials for soundproofing
Now for the practical bit, which materials should you use to soundproof your campervan? There are loads of options and, just like with thermal insulation, it’s about combining materials to get the best result.
Absorbing materials – catching the sound waves
To block direct sound like traffic noise from outside, you need materials that absorb sound waves and stop them bouncing around. Foam products and mineral wool, such as Armaflex or fibreglass insulation, are great choices here. These materials absorb sound by creating tiny air pockets where the sound waves get “trapped” and dampened. You can use them in the walls, roof and floor to reduce both noise and resonance.
If you drive long distances in a day, road noise can get tiring quickly. If you want to reduce sound from the wheel arches, it’s easy to mix up the difference between absorbing sound waves and stopping vibrations.
The most effective way to insulate around the wheel arches for tyre noise is to start with an absorbing material like Armaflex (or similar). And don’t forget that textiles not only make the space feel cosy – they also absorb sound that would otherwise bounce freely around the van.
Combining thermal and sound insulation
One of the best ways to get both a quieter and warmer interior is to combine your soundproofing materials with your thermal insulation. Many damping products we’ve mentioned also work as thermal insulation. Armaflex, for example, is used to insulate against heat and cold, but it also helps absorb sound. That means you get double benefit for comfort and noise at the same time.
However, we still recommend combining Armaflex with a mass insulation such as wool.
An extra layer of reflective material like Reflextex or foil insulation can also help block both heat and sound, especially if you place it in strategic spots, such as behind wall cladding or under the floor.
Tips for effective soundproofing in your campervan
Insulate under the floor: The floor can be a huge source of noise, especially from the road. A thick layer of damping material under your flooring will reduce vibrations and make the ride much quieter.
Use textiles: Soft materials like rugs, curtains and upholstered furniture also absorb sound and prevent it from bouncing around. A cosy blanket or some cushions aren’t just comfortable – they’re sound-dampening too.
Cover all key surfaces: Walls, floor and roof are obvious starting points – but don’t forget the doors and wheel arches, which can be major noise sources. Adding damping here can make a big difference.
Seal gaps and holes: Sound loves squeezing through even the smallest openings, so make sure to seal around windows, doors and any other gaps. Weatherstripping and expanding foam can be simple solutions.
In summary
A combination of direct and indirect soundproofing is the key to a calm, peaceful campervan.
By using the right materials in the right places, you can create a quiet and comfortable space whether you’re parked in a noisy city or out in the countryside. And as a bonus, with the right insulation your van will also be warmer in winter and cooler in summer – a real win-win.
Want to read and learn more about building your own campervan?
- Read our guide on how to choose the right base van for your campervan conversion.
- Wondering how the electrical system works in a campervan? Click here.
- Want to understand electrical safety before you design your van’s electrical system? Click here.