Welcome to the wonderful world of RV and van insulation.
If there is a topic that divides the #vanlife community more than van insulation, I’ve yet to find it. Insulation is the rabbit hole of all van conversion rabbit holes. 100 different products, 1000 different ways to do it and 10,000 different voices, all contradicting the other. So, with that in mind, let’s take a couple of deep breaths, and dive right in.
In this super-guide, I’m (Hi, I’m Charlie) going to take us back to basics.
Let’s discuss exactly what insulation does, how insulation does what it does, and how best we can implement it into our van build.
I’ll be backing all of this info up with our own personal real world findings from a life lived on the road.
What is insulation?
This seems like a good place to start doesn’t it!
To put it simply, insulation is any type of material that can be used to reduce heat flow from one space to another. This reduction in heat flow happens by either absorption, reflection, or a combination of the two.
There are many different kinds of insulation. These types include soundproofing, electrical and thermal insulation. We will be discussing thermal insulation here, which is defined as something that reduces heat gain and heat loss by providing a barrier between two environments of differing temperature.
What is heat flow?
Insulation’s number one job is to interrupt the flow of heat. This flow of heat is what is occurring when you lose or gain heat in an environment.
Heat will naturally flow from a warm area into a cool one.
For example, during winter months, if you open your front door, heat will rush to escape the warm space such as your home into the cooler outdoor areas. During the summer months, it works in reverse, the hot air will try to infiltrate into the cooler areas, such as your home.
By slowing the passage of heat flow, insulation can help to keep an area such as the inside of your van much more comfortable. Van insulation can allow you to retain your optimum room temperature for longer, and in a much more efficient manner.
There are 3 heat flow mechanisms that transfer heat from one thing to another:
Conduction heat transfer
This is the process that allows heat to transfer directly through matter. This is due to a difference in temperature between objects.
Lets get super geeky now, you ready?
Conduction happens when the temperature of molecules within a substance increases, this increase in temperature creates strong vibration of the molecules. These vibrating molecules then collide with surrounding molecules (ie – the other object that is touching the initial substance) and start to vibrate them too. This results in the transportation of energy into the part of the new object that is touching the hot one. Whoa, geeked out.
Simply put, this means that whenever two objects directly touch, heat will transfer from the hotter to the colder one. The objects which allow that transfer are called conductors. Some materials are better than others. Metal is a great conductor. Insulation is not!
Examples of Conduction
- A warm hand holding a cold one. The warm hand will transfer its warmth to the cold one.
- A metal fork resting in a pot of hot pasta. Watch out when you pick the fork up!
Convection heat transfer
Convection isn’t something we really need to worry about when discussing van insulation methods, but seeing as though we are on the insulation train now, let’s go there anyway. Toot toot!
Convection is heat transfer by movement of actual matter, and not by vibrating molecules within that matter (see conduction above). This movement of matter is only ever in fluids, including liquids and gases.
Examples of Convection
- Boiling water. The heat from the stove top passes from the burner into the pot. The water at the bottom of the pot is then heated. This hot water rises and cooler water moves down to replace it, this cooler water gets heated and itself rises, causing a circular motion.
- Car Radiator – your car’s radiator pushes warm air out at the top and draws in cooler air at the bottom.
Radiation heat transfer
Radiation refers to the movement of heat in electromagnetic waves. This form of heat transfer does not need molecules to travel through in order to transfer heat.
With radiation heat transfer an object does not need to be in direct contact with the other in order to transmit heat.
Examples of Radiation
The best example of radiation heat transfer is the sun. Whenever you feel heat on your skin while standing in view of the sun, this is caused by radiation, which travels on electromagnetic waves bazillions of miles through space to warm you and give you that summer tan.
How does insulation work?
Insulation’s number one job is to interrupt heat transfer. .
Heat will naturally flow from a warm area into a cool one via 1 of 3 ways – conduction, convection or radiation transfer.
Most common insulation works by utilising materials that contain millions of little, itty bitty pockets of air. Air is a super insulator, and it is the tiny trapped pockets of air within the insulative material that give nearly all types of insulation their ability to interrupand resist heat flow. This thermal resistance is what is known at the R-value – the resistance value.
What is an insulation R-value?
The R-value (insulation resistance value) is a measurement that notes the quality of thermal resistance a product has. It’s pretty simple – the higher the product’s R-value, the better the thermal resistance the product will be able to provide, or put another way, the greater insulating effect it will have and the more it will be able to save you money in energy consumption costs.
R values range from 1.5 to 7, and the higher the number is, the more effective the product is at resisting heat flow.
The R-value of a product is reached with the formula = Thickness (m) / Thermal conductivity (W/mK)
As you can see by the formula above, there are two factors to consider that affect an insulative product’s thermal resistance:
The thermal conductivity of the insulation.
The thickness of the material.
Both of these factors combine to create an R-value.
Most of the time in large spaces, increased insulation thickness is a more economically efficient option than using a product with a lower thermal conductivity. But, in a van conversion, this typically isn’t possible.
Vans, caravans and RVs don’t usually have thick walls or huge attic ceilings that we can fill with thick insulation batts. That is why it is important to be aware of product R-values, as then you can make the best determination about which insulation gives you the best thermal resistance while taking up the least amount of space.
What is the best R-Value for Van Insulation?
Insulation comes in lots of different structures and various materials. These include foam, foil and bulk, just to name a few. You may be wondering which of these has the best R-value. The easiest way to consider this question is to start with the idea that there really is no “best” R-value. Crazy I know, but really, it’s true. It’s what works best for your situation that makes the most sense.
When converting a van and planning your insulation you need to consider a couple of things.
- What kinds of climates are you going travelling into?
- How much money do you have to spend?
Both of these will impact your insulation choices dramatically. For instance, if you are insulating for winter, then you will need much higher R-value products, where-as if you are insulating for summer, a lower R-value can be used, assuming you have lots of active ventilation, such as windows and exhaust fans. If you installed high level R-value insulation in a van that will be spending its time in hot climates then this would potentially be unnecessarily expensive and wasteful.
Different types of insulation and their R-values.
The three main types of insulation we will be discussing for van conversions are:
Foil insulation acts against radiant heat transfer by deflecting radiant heat with a reflective surface. It can be cost effective in some circumstances. A great example of foil insulation is a car sunshade.
This is the most commonly used type of insulation, and most of the insulation options we discuss in this article would fall under this category.
Bulk insulation is created with millions of tiny bubbles of air. These bubbles of air trap the hot air in, and don’t allow it to pass. This type of insulation comes in a whole range of materials we will discuss later in more depth, these include ; wool, fibreglass, polyester and recycled paper.
This is the newest of the insulation tech. Spray insulation is a foam insulation that gets sprayed into position. The foam then expands into a thick, and effective insulation.
Spray insulation is moisture resistant, but is also more flammable than traditional insulation. This can definitely be installed by yourself, but it really is worth having done by a professional as it has the potential to go horribly wrong, and can be a nightmare of a process to remove if there is an error. Spray foam typically has the highest R-value of all of the insulation products.
What is a Thermal Bridge?
A thermal bridge or thermal bypass is an area where there is a higher thermal conductivity than the areas surrounding it. Because of this, a path of least resistance for heat transfer is created. Essentially a heat flow super highway that cheats a path through your insulation.
Thermal Bridges reduce the overall thermal resistance of a space, and impact the amount of energy needed to cool or heat said space.
For example, in our van, we stuffed the ribs and interiors of the original van walls with insulation, but the actual van rib metal itself was still considered a thermal bridge, as the metal of the ribbing connected directly to the metal of the roof, which would be conducting the exterior temperature. We covered the ceiling ribs and walls with wood material, which provides insulative properties in its own right.
We just had to realise that some insulation is better than none, and that our van fully insulated with a bit of thermal bridging here and there will still be way more effective than no insulation at all.
If you are looking to travel in very cold climates, it would be worth adding some layer of insulation between your thermal breaks and your interior walls. Though this then impacts space inside the van. It’s a compromise of sorts, as is practically every decision in the van.
What is a Vapor Barrier?
Ahh and here we are, one of the most hotly debated van conversion topics there is. Are vapor barriers a good idea? Let’s look closer.
A vapor barrier is typically a plastic or foil sheet used to prevent condensation from forming in your insulation, and more importantly, forming on the metal of your van. In a worst case scenario this condensation can lead to rot and mould throughout your insulation, and also rust on your van metal surfaces. This condensation is typically caused by the interior temperature of the van being different from the exterior temperature. Condensation can also be caused by cooking, drying wet clothes, or simply our natural breathing.
So, that’s what a vapor barrier is, now the more important question…
Do I need a vapor barrier in my van?
Forget Ali vs Foreman, or The Avengers vs Thanos, this right here is the real battle of the ages!
In the red corner… The argument FOR a van vapor barrier!
Without an adequate vapor barrier your van will rust out. You create lots of moisture through breathing, cooking, drying clothes or running a heater, and this moisture will travel on the air to the colder metal interior walls of your van. Once there, the air condenses into water, and before you know it, will cause rust and doom. To stop this we need a barrier between the van’s living space and the walls!
In the blue corner… The argument AGAINST a van vapor barrier!
The number one point from the team against is that it is practically impossible to completely seal off your van insulation from moisture. If there are gaps, the moisture rich air will find it. Then… oh oh, because there is some sort of vapor barrier, the moisture will condense and have a hard time drying out, due to the lack of adequate air flow and ventilation.
And, trust us, there ARE gaps.
- If you have drilled anything into the roof – solar panels, roof racks, then over time these may be susceptible to leaking.
- Drain holes along the bottom of walls.
- Plastic trip nipples (that keep the exterior trim attached)
- Rear pillar openings.
So, it’s kinda like one of those self fulfilling prophecies… You want to stop rust and mold from condensation, so you install a vapor barrier. The vapor barrier helps to cause rust and mold. What a cruel world.
The winner… at least according to us.
We belong in the red camp. You don’t need to worry about installing a vapor barrier.
Your best bet is to save all of the time and hassle and simply focus on the following two things, that when combined will allow you to sleep well at night knowing that you are safe from the perils of rust and mold:
- Use insulation materials that are water repellent or waterproof. This will stop any unwanted condensation and moisture hanging around longer than it should be.
Secondly, ventilation and proper airflow are your friends. If you make sure to focus on effective airflow, namely windows and roof exhaust fans, which allow your van to breathe, you will do a much better job at mitigating condensation, as well as creating a much more manageable environment, temperature wise, for you to live in.
How to achieve proper ventilation in a van.
A rooftop fan is a must in practically every van conversion. It needs to have an exhaust mode, to be able to suck air out of the van. These fans will help with both clearing any moisture in the van, and are also amazingly effective in maintaining comfortable temperatures.
The best ventilation is achieved with windows AND a roof fan. It’s a winning combination, especially if you are strategic about where you install your windows and roof fan.
Ideally you want as much space between your main window and your roof fan. This is because, when you have the window open, and have the fan set to exhaust, then the fan will be pulling air in through the window, through the van living space and then extracting it outside again. This creates a beautiful breeze through the van. If you had your window installed directly below your fan, then you would not be creating this breeze through the van, it would only be in the space between the window and fan. So the effectiveness of both your windows and roof fan really depends on where you install them.
In our van, we installed a window in the back left. This was next to our bed. We then installed the roof fan (MaxxFan Deluxe) in the front third of the living space. This meant that when the window was open and the fan was running, we were creating a breeze that would travel over the bed, and through the whole living space.
We installed a MaxxFan Deluxe in our van. We can’t recommend it highly enough. It’s most attractive feature is its ability to work in the rain, as it comes pre-installed with a rain hood.
The window we had installed was also able to be opened (at least partially) in the rain.
This is important, as it is during extended downpours, where you are cooped up in the van, that the most moisture can be created. This allowed us to be able to ventilate effectively – even in a thunderstorm.
What To Look For In Van Insulation.
Before we dive into all of the different insulation options you have, let’s quickly talk about what the most important points to consider are when choosing your insulation product.
Ease of installation.
Let’s face it, none of us are complete pros at this. If you are completing your own van conversion then there is definitely a level of learning you are willing to do. But, sometimes we can bite off more than we can chew and do more damage than good. A good example of this is van wall warping when using spray foam.
Here at BYDV we think ease of installation is an important factor to consider for the average DIY’er.
High R-value per inch.
The more R-value you can pack into an inch of space, the more powerful your insulation will be.
Bang for your buck.
It’s not only about R-value per inch, but also R-value per dollar!
Does the insulation have links to health issues, especially respiratory issues? Is it made of non-toxic materials?
Resistance to moisture, mold, and mildew.
Water resistant or waterproof insulation is definitely worth considering.
Most common insulation materials for van conversions.
There are a tonne of different materials you can use for insulation.
Here is a handy chart that contains the need to know R-Value number for a wide variety of insulation materials.
|MATERIAL||R-VALUE PER INCH|
|FIBERGLASS BATTS||3.7 to 4.3|
|POLYISO BOARD||6 to 6.5|
|CLOSED CELL SPRAY FOAM||6.5 to 7|
|OPEN CELL SPRAY FOAM||3.5|
|LIZARD SKIN||0 – no data|
Ok lets now dive into all of the different insulative materials you have to choose from when insulating your van.
Thinsulate Insulation Review
R-VALUE per inch = 3.3
If you have ski gloves, jackets or boots, there is a good chance that they are insulated by 3M Thinsulate. This was 3M’s original intention when Thinsulate was created, but as of late it has become, by way of the marine industry first, very popular in van conversions.
It’s easy to see why too. It is hydrophobic, which is a fancy way of saying water resistant. It is also flame resistant and meets various international motor vehicle safety standards. Another positive is that it has no discernable odor. Some other insulations do, and you are left smelling them for weeks after your van build is completed.
Thinsulate is water resistant, but still allows moisture to pass through the insulation. This is good as it means moisture won’t get trapped behind the insulation, and can be evaporated with proper ventilation.
Thinsulate is easy to cut and manipulate (very important in a van full of tight spaces). As well as being non-toxic. It’s easy enough to install too; It is a light enough material that it will typically hold in place just using spray adhesive.
Where Thinsulate falls short is its actual effectiveness as an insulation. It has an r-value of 3.3 which is the lowest on the table. Compound this with the fact that it is also one of the most expensive and, unless you have deep pockets, it becomes hard to paint a good case for its use.
Also, in a world where every spare bit of space counts, you want your insulation to be super efficient. Polyiso board has twice the insulative power per inch (R-7 vs Thinsulates R-3.3). It’s for this reason that we think Thinsulate isn’t the greatest option out there.
- Non Toxic
- Easy to cut and manipulate
- R-value is low compared to similar options
Our Thoughts on Thinsulate
There is no doubt it is a good product, backed by one of the most reputable brands in the world, 3M. But there are cheaper options that will do a better job at insulating your van, such as sheeps wool, at a fraction of the cost.
Expanded Polystyrene (Eps) Board Insulation Review
R-VALUE per inch = 3.85
EPS Board is a viable option for insulating your van. It works fine and is the cheapest of all of the rigid foam board insulation materials. It is basically the same as styrofoam. The benefit of this is that we all know how well styrofoam insulates. From older style coffee cups to cool boxes, it stops heat flow in its tracks. But, if you’ve ever held a foam cup, you know how fragile it can be.
Would it hold up to the rigors of the road, or would the insulation vibrate itself apart in your walls? I really don’t know the answer to that, but to be honest, it would give me reason to second guess its use. It’s hard bloody work to have to take apart your walls or ceiling to fix broken insulation boards that are rattling around.
That being said, if you are on a tight budget, it does give bang for buck money wise.
Also, the EPS board is really, really light. The board is less dense than XPS or Polyiso board, and therefore it is the lightest, as more of it is made up of air pockets. So if weight is a major concern for you, then this product could well be worth taking a closer look at.
EPS board is also one of the best, most consistent rigid board insulation products at a range of temperatures. Where Polyiso’s R-value decreases substantially at low temperatures, EPS board doesn’t have that problem. It provides consistent performance, no matter the temperature.
EPS Board PROS
- Cheapest of the rigid foam board options.
- Easy to cut and shape
EPS Board CONS
- R-value is nearly half that of Polyiso board.
- It may be more susceptible to vibrations
Our Thoughts on EPS Board
If you’re on a budget, this is a fantastic option. It has fairly good R-value when compared to batts, and can be easily cut to shape, making the installation process a lot easier.
However, it has a lower R-value than the other rigid foam options. And it may be more fragile. Which isn’t the best idea for a van that will be travelling over all sorts of roads and terrain.
We think there are better rigid foam board options.
Polyiso (Pir) Board Insulation Review
R-VALUE per inch = 6 to 6.5
Polyisocyanurate board (polyiso) is the material we predominantly used in our van insulation. Poliso board is a real ass kicker when it comes to R-value. The board comes in at a R-6.5. As far as rigid foam panels go, this is by far the best material from an R-value perspective. The only thing that comes close to it is closed cell spray foam.
Polyiso is a rigid foam board that typically comes foil-faced on one or both sides. This foil provides a radiant heat barrier, so long as it is installed with an air gap.
It is moisture resistant and is a non toxic material.
Polyiso also has superior fire resistance when compared to other rigid foam products. This is because it is a “thermoset”. It can form a protective char layer, whereas other rigid foam board is “thermoplastic”, and will melt and drip when exposed to a heat source.
We installed this in our van because of it’s incredible R-value of 6.5. We also like that when installed with an air gap, the reflective foil-facing actually acts as a radiant heat barrier. When this occurs, the R-value actually goes up to a R-7, which is really amazing.
There is a pretty major negative to PIR polyiso board, and that is its performance in very cold climates. Once the temperature gets colder than 15c / 50f it’s performance starts to deteriorate. Slightly at first, but by the time you get to -20c / -4f the r-value may have deteriorated by as much as 30 percent when compared to EPS board.
That means that a PIR board is great if you keep it warm. A weird thing considering it is an insulation product!
We decided that we would not be going into climates that regularly sat in those very low temperature zones. Because of this we feel that, for our needs, the PIR board was second to none.
Polyiso (Pir) Board PROS
- Great R-value
- Sturdy construction
- Easy enough to cut to cut to shape and install.
- Great fire resistance
- Cost is cheap when considering the R-value.
- Packs a lot of R-value into an inch, which means more insulation performance in less space. Perfect for a van conversion.
Polyiso (Pir) Board CONS
- Performs badly in very low temperatures
- Can be messy-ish when cutting it up to size.
Our Thoughts onPolyiso (Pir) Board
No doubt this is one of the heavy hitters of van insulation. We installed it in our van and were very happy with the results.
Xps Board Insulation Review
R-VALUE per inch = 4.6
Extruded polystyrene board, or XPS for short, is another of the big three options when it comes to rigid foam board insulation, the others being EPS and Polyiso.
Like its big brother Polyiso board, XPS board comes packed with a high R-value. It’s not quite the 6.5 or Polyiso, but rather 4.7 (which is still quite high).. This is better than any other insulation in our comparison except for spray foam (R-7) and Polyiso (R-6.5).
XPS board is also like its rigid board brothers in the fact that it is also impervious to moisture, and it is highly condensed which makes it strong. So if you are thinking of laying an insulation subfloor, then this or Polyiso would be your ticket. It’s so strong that some van lifers have even gone to making rudimentary cabinets out of it.
XPS is not very green however, as its manufacturing process uses hydrofluorocarbon (HFC) blowing agents that are very potent greenhouse gases, in fact they can be over 1300 (yep, you read that correctly) times more potent a greenhouse gas than carbon dioxide. However, there is a ray of light. XPS manufacturers have stated that they will stop using HFCs in their manufacturing process by 2020, whether this has happened for all brands, I’m not sure. The HFCs are being replaced by HFO blends, which are hydrofluoroolefins.
Xps Board Insulation PROS
- High R-Value of 4.7. This is second only to spray foam and Polyiso board.
- Performs better in super cold conditions than Polyiso.
- Impervious to moisture.
- Highly condensed = strong.
Xps Board Insulation CONS
- Not green (though this is changing a little bit).
- Can be messy-ish when cutting it up to size.
Our Thoughts onXps Board Insulation
A solid choice. This is also much more widely available than PIR board. At least that was our experience. We really had to look for a PIR board supplier, whereas every place we enquired stocked some XPS.
Sheep Wool Insulation Review
R-VALUE per inch = 3.6
Sheep wool is on the top of many peoples’ lists when it comes to campervan insulation.
In terms of eco-friendliness, sheep wool is the gold standard. It is made from 100 percent sustainable, natural materials. It is non-toxic too, which is vital in small living spaces such as a converted van.
Sheep wool is known for its breathability. Compounding this with its natural ability to release moisture and allow it to pass through the wool, means that sheep wool can be very beneficial in moisture control, and can save you from going down the vapor barrier rabbit hole.
It is also quite sound absorbent. We think using a material that has an strong element of sound absorption is much better than sticking the heavy sound deadener material throughout your van – we did just that and kinda regret it. Sound deadener rubber is heavy and expensive. Much better to install an insulation material that does the job. 2 birds, 1 stone kinda deal.
Sheep wool is also easy to install. You can handle it with your bare hands, with no itching or skin reactions to worry about (unlike fibreglass based insulation). It’s easy enough to cut the sheep’s wool batts to size.
The downside to sheep wool is that it is a more expensive option than other insulation materials. So it may be out of reach of budget van conversions. Also, because it has a lower R-Value, more of it will have to be used to even start to compete with board insulation like PIR and XPS board, this means more costs and possibly more wall space needed, which in turn can mean less interior space. This point applies to all batt type insulation options though.
Oh, and if you’re wondering if any sheep were harmed during the making of the sheep wool batts, then you wouldn’t be the only one. The thought of them being harmed in order for you to build your van is a terrible one. It is for this reason that you want to make sure that you choose an insulation provider that takes animal welfare seriously. Most countries in the world ban harmful shearing practices, and instead promote responsible sheep farming – though it is worth doing a little bit of research on the insulation provider you are leaning towards buying from, just to make sure that they are one of the good guys.
Sheep Wool PROS
- Breathability and Moisture control
- Sound absorption
- Ease of handling and installation
- Sustainable, natural materials.
- Non toxic
Sheep Wool CONS
- A little pricey
- Lower R-value than some other options.
Our Thoughts on Sheep Wool
Sheep wool is a great choice. It is natural, non toxic and has a high R-value. What’s not to like!
Fibreglass Batts Insulation Review
R-VALUE per inch = 3.7 to 4.3
Since the late 30’s when fibreglass insulation was introduced, it has remained as the insulation material of choice for both residential and commercial construction. It is energy efficient due to a strong R-value, and, more importantly… It is cheap. Really cheap. Especially when compared to some of the other options.
However, there is no such thing as a free lunch, and when it comes to fibreglass, there are a few negatives that need to be discussed up front.
The first is that protective gear needs to be worn when installing these batts. This includes long sleeve clothing, prober eyewear and N95 face masks. The tiny fibreglass slivers can lodge into the skin. This can cause allergic reactions and intense itching rashes.
The face mask is necessary because fibreglass is definitely not something you want to be breathing in. The fibres can be infinitesimally small and can cause a whole range of serious respiratory issues. There is data to suggest that fiberglass in the lungs can be a cause of cancer and lung disease. Some manufacturers supply the material in sealed batts, covered with perforated plastic film. While this plastic seal is brilliant for mitigating the issue of breathing fibres, it actually creates a vapor barrier, which we believe can actually be worse for your van.
Also, depending on the material provider, some fiberglass insulation uses formaldehyde to bind the fibers together. This can leak out into the air overtime. And guess what, that is dangerous too. Formaldehyde has also been linked to cancer.
Fibreglass insulation PROS
Cheap cheap cheap.
- Does a great job insulating.
- High R-value compared to other batt options.
- Insects don’t eat it.
- Can be made from recycled glass, meaning a reduced eco footprint.
- Did we mention cheap?
Fibreglass insulation CONS
- Protective gear needed when installing.
- Severe health consequences if breathed in. Links to lung disease and cancer.
- Fibreglass is known to settle and sag, decreasing its R-value over time.
Our Thoughts on Fibreglass insulation
The negatives far outweigh the positives on this one. We think it best to stay away from fibreglass.
Sure it is cheap, but you’re only going to be insulating a van not a 2 storey home, so the price between fibreglass and a safer, non-toxic option like sheep wool is not going to break the bank too badly. We’d go with a safer option every day of the week.
Denim Insulation Review
R-VALUE per inch = 3.7 to 4.3
Denim insulation comes in batts. These batts are made from recycled blue jean materials.
The insulation is non-toxic, which makes it way more safe to install when compared to other types of material. Denim’s R-value is strikingly good, having the same R-value as Fibreglass. Unlike fibreglass, denim insulation can be handled easily and does not need protective clothing in order to stay safe when installing it, though you would still be wise to wear a mask as the fibres are still quite small.
Denim is expensive, though not the most expensive batt option around, that honor goes to rockwool. In fact denim happens to be nearly twice as cheap as rockwool, with very similar insulation performance.
How Denim Insulation Is Made
Old denim clothing is literally recycled into insulation. We think this is such a great, eco-friendly idea. So, how does it happen?
Well, old denim is rounded up and shipped to a recycling centre.
Buttons, zippers, velcro and any other extraneous items are taken off of the recycled denim jeans.
The denim then goes through mechanical shredders and is all grinded up into small pieces.
These small pieces are then shredded once again by a different machine. This second shredder is able to shred individual pieces to a fibrous state.
The fibres are treated with borate flame retardant to make them fire resistant.
Then the fibres are then pressed together into large batts. These large batts are then cut to typical batt size. Pretty cool huh.
Denim Insulation PROS
- Price is great.
- Practically the same R-value, but half the cost
- The most Eco friendly option as this insulation is almost entirely made from recycled materials.
Denim Insulation CONS
This denim material is relatively expensive and also, it is an absorbent material. Both of this means that it can lead to mold and rust on the inside of your van surface, as it stops proper ventilation.
Denim batts are considered harder to cut and manipulate as denim insulation comes in denser batts than most other materials.
Denim insulation is packed so tight into each batt that it doesn’t stretch easily. With other materials like fibreglass, you can pull off chunks of it quite easily. You can still do that with Denim but it is much harder.
Our Thoughts on Denim Insulation
It’s a much better choice than fibreglass. And we LOVE the fact it comes from recycled materials. However, it is relatively expensive, a little bit harder to install due to each batts density, and it has a tendency to absorb and retain moisture – which in a van can lead to mold and rust. I wouldn’t fit out an entire van with this stuff.
Closed Cell Spray Foam Insulation Review
R-VALUE per inch = 6.5 – 7
Without a doubt, spray foam when installed correctly is the gold standard of van insulation. It has an R-value of 7! That is double that of fiberglass, denim, sheep wool, and more. If you are looking for the bees knees of insulation, this is it.
So what exactly is sprayfoam insulation? Spray polyurethane foam (SPF) is a foam that is coated onto a surface in the same manner as when spray painting. The foam then expands once it contacts the surface. It expands rapidly and creates an insulating barrier.
Spray foam can expand between 25 to 100 times the amount of the actual applied thickness.
It is for this reason of rapid expansion, that if you decide to go the spray foam route, it is worth getting it done professionally. It is tricky business to say the least.
Aside from the high R-value of 7 that spray foam provides, it also does a host of other handy things.
Spray foam insulation creates an impermeable vapor barrier for the surfaces it is applied to. I know we have stated vapor barriers are not needed, or in some cases can be counter productive to protecting your van from rust and mold, but this is because most vapor barriers fail. Well with spray foam, the insulation is actually coated to the surface, and because of its rapid expansion, it goes into every nook and crack. For this reason we believe the vapor barrier it creates is impermeable and will indeed protect your surfaces from moisture, rust and mold.
The spray foam is also a brilliant choice for a van because it acts as an incredible sound deadener. It is applied and sticks to the wide sheet metal sides and roof of a van. This means that it will help to absorb any sounds passing through very effectively, giving you very good nights sleep when you happen to be parked next to a highway. If you go this route and choose spray foam, then you definitely do not need to waste money on other rubber sound deadening materials.
It’s not all sunshine and rainbows though, there are some definite negatives to consider. The first is cost, it’s not cheap. You can get the do it yourself kits, which make it a little bit cheaper, but in my opinion, you want a pro to do this. They’ll do it quicker and neater than you ever could.
If you do decide to do it yourself, you have to be careful of using too much and warping your outside walls. It expands rapidly and if you spray it into a part of your wall where the rapidly expanding foam cannot sufficiently escape, it will find the space to continue expanding by pushing out the sheet metal sides of your van. Not a good look.
Spray Foam PROS
- Incredible insulation quality. R-value of 7 – best in class.
- Creates an impermeable vapor barrier, protecting the van surface from moisture, mold and rust.
- Fantastic sound deadening qualities.
- When done correctly, it can be a relatively quick installation process.
Spray Foam CONS
- Very pricey. DIY kits will still cost you upward of $400 to do a van. A professional could be nearer to $1000 depending on where you are located.
- The cutting down process, where you cut off all of the extra foam that has been expanded, can be very messy.
- Its flammable! Spray foam is a fire accelerator, this means, not only does it catch fire and burn, but as it burns it releases chemicals that accelerate the rate of burning.
- Also these chemicals have been known to make people blackout and lose vision. Pretty serious stuff.
Our Thoughts on Spray Foam Insulation
There are some really good things to like about spray foam. If I was converting another van today, spray foam would definitely be on my short list. I like it’s R-value of 7 and I like that I can get a professional to install it.
But, there are concerns. Firstly, it is expensive, though I think the high R-value offsets that cost somewhat. Secondly, it is not eco-friendly at all.
There is no recycling element to its creation and it contains nasty chemicals. Thirdly, it is very combustible.
I am erring on the side of no on this one.
Polyester Insulation Review
R-VALUE per inch = 3.5
Polyester is a fantastic, cheap alternative to traditional fiberglass insulation. It has roughly the same R-value per inch as fiberglass and offers similar performance in terms of energy consumption and sound absorption.
Polyester is made from Polytheylene Terephthalate (PET) fiber. This is the same fiber that is commonly used in polyester bedding and clothing. Most polyester products are made from recycled materials such as plastic packaging and plastic bags. It is odourless and safe, and importantly, does not produce any greenhouse gasses. It negates all of the negatives of fiberglass, such as needing protective gear to install, and it also doesn’t come with any of the same health risks that fiberglass does. The fibers are non-irritant, non-allergenic and non-toxic.
These batts are made from super thin polyester fibers. Because of their spun form that is woven into a thick structure, the fibers create almost no dust at all. This eliminates both the itch and dust problems of fiberglass products.
This same thick structure means that the batts avoid deterioration over time, as is prone to happening with other materials such as denim and traditional fibreglass batts.
In a fire, polyester is still considered a combustible product, but it has a unique benefit, in that its fibres will tend to resist smoking and burning. Instead, in a fire the fibers of the batts will likely melt together and then part away from the contacting surfaces.
Polyester batts are also quite environmentally friendly. This is because they typically use up to 85% recycled materials, and not only that, but the insulation itself is able to be recycled.
Polyester Insulation PROS
- Offers comparable R-value to other materials such as fibreglass and denim insulation.
- Environmentally friendly. Commonly made from up to 85% recycled materials.
- Safe to install. No personal protective equipment needed.
- Thick structure. Holds shape.
Polyester Insulation CONS
- Cost is roughly 2-2.5 x fibreglass for similar R-value.
- Not completely fire retardant.
Our Thoughts on Polyester Insulation
We used polyester insulation in our van, along with polyiso board. We found it’s R-value, safety of installation and the fact that it is (depending on brand) made of up to 85% recycled materials, a winning combination.
We used it in the lower walls of the van, and as stuffing in the hard to reach nooks and crannies in the walls and ceiling.
How Did We Insulate Our Van?
Ok, so now we have shown you all of the options, I can give you the lowdown on what we used and why. Also, after living in the van full time I can tell you what we feel worked… and what didn’t.
In our van we used a mixture of
- polyiso board
- polyester batts.
Polyiso board was a pure R-value play. It gave the best insulative quality outside of spray foam. We were tempted to take the spray foam route, but I felt there was too much that could go wrong doing it ourselves (bulging exterior panels, horrible messes, additional costs of first time use), and if we paid for it to be done by a professional, we were robbing ourselves of the satisfaction of knowing we had done the whole conversion ourselves. I know, a little bit silly, but I’d be lying if I said it didn’t influence the decision.
The polyiso board was used in the ceiling and walls. It was doubled up in the larger wall cavities to give a super R-value of 13.
The polyester batts were used pretty much everywhere else. It could be pushed into corners and helped fill in any gaps the polyiso board couldn’t reach.
After living in the van full time, I’ve got to say that I really think we made the right choice. On cold nights, the insulation retained our body heat within the van, so in the morning we could jump out of bed, and while it wouldn’t be toasty warm, it wasn’t spine chillingly cold either. It is worth noting that we didn’t travel into any snow covered regions. Our coldest nights likely didn’t get below 0 deg celsius / 32f.
In the hotter destinations we travelled, it seemed to stay much cooler than outside, even when the van was parked in the direct sun. This was likely due to the combination of effective insulation as well as good airflow created by our window and exhaust fan locations. We often had mornings at the beach and then would happily return to the car park for a midday nap in the van. The temperature could be in the high 30’s outside (nearly 100 fahrenheit) and we’d be happily snoozing away with our window slightly open and our MaxxFan set to exhaust, pulling the breeze through the window and across our bodies.
Window Covers For a Van
There are 2 main reasons you will want to create high quality, well fitting window covers for your van.
Light – the ability to stop any light from entering or exiting your van is a must when travelling.
You may be parked in a car park, next to a highway, or smack bang in the middle of the city, and without blackout window covers you can kiss a good night’s sleep goodbye. Also, If you are going stealth, you really don’t want light exiting your van as it is a dead give away that you are camping inside.
Privacy – People are nosey. And you will have people come around snooping and looking in your windows. This is especially true in dodgy camp sites or areas where break ins are regular occurrences. It’s always best to leave your van window coverings up whenever you leave your van.
How To Insulate Windows In A Van
Have you ever heard the saying “you’re only as strong as your weakest link”? Well, when it comes to insulating a van, the weakest link will be your windows.
You see, apart from stopping the cold or hot wind from entering your van, your windows provide next to no insulative properties at all.
So if you spend all this time insulating your whole van for a snowy winter, then don’t do anything about your windows, you’re really just undermining all of your hard work.
Let’s look at a couple of different window insulation options at different levels of price point and effort, so you can get the job done.
Insulating Windows In A Van Quickly and Cheaply
The quick and cheap method is to use a reflective bubble wrap such as Reflectix.
There are other brands out there, and knockoffs on ebay that you can purchase. They all do the same thing, and that is to create a great “radiant” barrier that is incredibly effective at reducing the amount of heat entering your van from direct solar radiation. Essentially you are going to create your typical car sunshade.
Make sure you measure your widest window, and order a roll of reflectix that is wide enough to cover that window. You’re also gonna need a permanent texta and some scissors.
Step 1 – measure twice, cut once.
Measure the window you are looking to insulate. Make sure to measure the inside of the window, not the exterior of your van. Add a ½ inch to your measurements.
A lot of van windows are not perfectly square, so you want to make sure you are measuring across the top, the middle and the bottom horizontally, and the left, middle and right side when measuring vertically.
Step 2 – create the outline.
Join your measurements up to make an outline of your window.
Make sure to include that extra half inch of outer diameter. This is purely buffer, to add a margin of safety. It’s much easier to trim off excess Reflectix than to add it back on!
Step 3 – cut it out!
Cut your reflectix following your awesome outline. You’ll be left with one piece of reflectix, cut to your window size, including a margin of safety.
Step 4 – put in place
Simply put the window covers in place now. Push the reflectix into place firmly, including along the edges.
For some of the windows, the reflectix may hold in place because of the additional ½ inch cut. If not, you can add velcro or magnets (we used magnetic tape) to the window and reflectix. This will then hold them in place. Make sure to use pro level velcro or magnet tape though, otherwise you’ll find that the radiant heat from the sun will make short work of the cheaper glue and the velcro will not adhere to the window or frame.
Insulating Windows In A Van With High Quality Window Covers
First thing to note is that a lot of window cover DIY instructions on the net are typically just using reflectix as the window covering material. This is great on a hot day in direct sunlight, and practically worthless any other time. If you are in the snow and it’s -10 degrees celsius overnight, then guess what, a little bit of bubble wrap ain’t really gonna stop heat transfer from sucking all the heat out of your van.
So, what you really need to accomplish for effective van window coverings is a bit of both radiant and thermal insulation. You need the reflectix to work as a radiant heat barrier, then you also need an insulative fabric to provide a good level of insulation as well.
Fabrics you could use as insulative material are
- 3M Thinsulate
- Thick carpet
Otherwise another way to create an insulative layer is to use a thinner material as a sort of container for your insulative material. Think of a pillow case.
Using the cardboard template, this insulative pillow case can then be attached to the Relfectix layer. This will give you both the power of radiant insulation as well as the insulative properties of whatever material you decide to use.
It could made of polyester, sheeps wool, or denim batt thermal insulation. Pack the pillow-esque compartment with as much as you need. Just make sure to use an insulation that doesn’t break down or pose a risk to your health (such as fibreglass!), as you will be constantly using, moving and storing these window covers. Then it is just a matter of adding magnets to allow the new window covering to stay in place.
Where To Buy Insulated Van Window Covers
If you feel that making your own window covers falls into the “too hard” basket, or you have left for your adventure without the window covers then there is another option – you can simply pay for them!
There are now a few places making the window covers, and we haven’t used any of them, so we can’t vouch for their quality, however, out of the products I’ve checked out online, these ones seem the best – VanMadeGear.com
They make covers for Transit, Sprinter and Promaster vans and are worth a look. The prices are a little steep, but, I’m sure the quality of them is high so the price may well be warranted, and will likely last you longer than any home DIY job. They are handmade in the USA.
Also, if your time is important to you, then it is well worth considering them, as DIY insulated window covers for a van can be one of those things that takes a darn sight longer than you think it is going to.
A Word On Sound Deadening In A Van
Just like insulation that stops heat flow, there is another insulation that’s just as divisive within van conversion circles. The insulation we are discussing now is sound deadening insulation. There are people who swear by it, and others who think it is a complete waste of time, money, and importantly, your vehicles allowable build weight.
Which camp do we fall into? Read on to find out!
What Is Sound Deadening Insulation?
Simply put, sound deadening is a material that reduces the resonance or volume of sound.
In van conversion this typically means a thick sticky rubber type material that can be applied to the wall, floor and roof panels of a van.
How Does Sound Deadening Work?
The goal of using a sound deadening product on your van conversion is to make the interior quieter, and less vulnerable to outside noise.
The biggest creator of noise transfer in your van will be the areas of the roof and walls that consist of large, thin sheets of unsupported metal. These sheets of metal reverberate. This gives the sheets of metal the ability to not only pass on sounds from outside the van, but in some instances, amplify them. For instance, if someone was to hit the side of your empty van with a stick, it would sound hella loud inside!
Butyl sound deadening products effectively do two things.
They weigh the sheet metal down, not allowing it to vibrate as much.
They absorb vibrations. The material makeup of the butyl sound deadening sheets is a soft malleable rubber substance which is absolutely brilliant at vibration absorption. So the pairing of weighing down the metal sheets, and the actual sound deadening material becomes quite a potent combination.
What Did We Do In Our Van?
In Our Ford Transit Van Conversion we did use sound deadener. We used as little of it as we could while still being effective.
Do You Need Sound Deadener In Your Van?
To be perfectly honest, it depends on a few things, but overall, we don’t really think so. Once you put up all of your insulation, then your interior walls, and ceilings, then your joinery, then your bed and seating etc, you will have so much material for any external sound to pass through, This is especially true if you are using batts of insulation and not rigid board. These batts will push against the larger metal sheeting of the van vehicle walls, essentially deadening them from passing through or amplifying outside sounds. If the outside sounds do still penetrate through to the interior of the van then there are still all the other materials to pass through before being of any concern to you and your ears!
Another thing to consider with sound deadeners is weight. This was the reason that we only used as little of it as we felt was necessary, and why we would hesitate to use it again. This is especially true once really got a sense of what will be installed atop of it.
The butyl sheets can add up in weight, and weight is a super precious commodity when doing a van conversion. You have to know your Tare weight (your vehicle’s weight when completely empty) and your GVM (gross vehicle mass).
What is between these two numbers is essentially what you have to work with. On some vans it may only be 800kg. This sounds like a lot, but this includes not only your whole van build but also you, your travel partner, your dog or kids, your food, water, clothes, bikes, plates and cutlery… you get the drift. So if you waste 40kg of that on sound deadening material, you have to contemplate whether it was worth it.
Examples Of Sound Deadening Overkill
If you are going to use butyl sound deadening sheets, I would suggest you don’t need to cover more than 30-50% of the bigger sheet panels on the van. Don’t go overboard. It’s not worth the time, money or loss of usable weight.
Installing Van Floor Insulation
Installing insulation underneath the van floor is one area that we were personally unsure about pursuing.
We found there were definitely a few pros and cons to weigh up when considering installing under floor insulation.
Van Floor Insulation CONS
- It costs money.
- It takes a fair amount of time!
- It will cost your vertical space in the van. Only about an inch, but still… in a van every single bit of space counts.
- Because heat rises, it is the least important part of your van to insulate. In fact, many van lifers choose not to insulate their floors for this reason.
Van Floor Insulation PROS
- Insulating the floor of your van will have some positive effects on mitigating heat transfer and allowing you to have a pleasant and comfortable environment within the van.
- Peace of mind. On a hot night you won’t be lying in bed going “If only I insulated the floor… It could have made all the difference”.
How We Installed Our Van Floor Insulation
After much toing and froing we decided it was best to insulate the van floor. We reasoned that we would be travelling to both the coldest and the warmest parts of Australia on our big lap and so we really should be prepared for anything.
Our van flooring was made up of the following layers
VAN METAL FLOOR
LAYER 1 : CORRUGATION FILLINGS
LAYER 2 : XPS BOARD
LAYER 3 : PLYWOOD FLOOR – 15mm thick
LAYER 4 : VINYL SHEET
We settled on XPS board as it offered the highest R-value for the minimum amount of space – which was a must as we did not want to sacrifice any more vertical height than we had to.
How To Install Van Floor Insulation
Our process to install underfloor insulation in our van was as follows.
- Tend to any rust spots and holes in the van floor.
Before beginning the van floor insulation process, you should make sure that you attend to any and all rust spots. This is vital in protecting your van as what may only be a small rust spot now can turn into something much more significant down the line, and once this flooring is down, you won’t be able to get to it again, without a lot of blood sweat and tears at least.
Each rust spot should be properly sanded back to bare metal. This bare metal should then be treated with an anti-rust protectant, and then painted. This ensures oxygen cannot reach the exposed metal, and that rusting will not occur in the same spot again.
If there are any holes in the van floor, where you can literally see through to the floor, these most definitely need to be fixed up.
The method we used in our van for filling any holes in the floor was sanding and painting the hole, and then once the paint had dried, using a caulking gun with Sikaflex to fill the hole. Simple and effective.
- Fill in gaps between ridges/corrugations on the van floor.
The floor of a Ford Transit Van isn’t actually flat. Instead, it is a floor made up of ridges and depressions. Some of these corrugations in the van floor are fairly close together, but others, for some reason, were a good distance apart. We were concerned this would cause the floor to sag in spots where the ridges were too far apart from each other.
To fill in the gaps between the ridges, we cut to size some 12mm (½ inch) thick wood strips. This was done so that when walking on the final flooring there would be no movement underfoot, no matter how slight.
We glued the wood strips to the van floor using Sikaflex Pro.
- Cut to size sheets of XPS insulation.
We wanted to cover the floor with the least amount of different insulation boards as possible. We managed to cut the insulation to shape using 3 XPS boards. In order to cut the right shapes, we used a mixture of cutting old cardboard boxes to size, in areas such as around the wheel arches, and we also used a good ol’ fashioned measuring tape. Worked a treat.
- Copy the outline of the XPS board to your plywood sheeting.
The reason this is the next step is because you want to use the XPS insulation you have cut to size as a template that you can copy over to the plywood sheeting. You’ll feel like a right fool if you glue your XPS board down and then realise that you should have used it as a template.
One important step you should take here is to make sure that your joins between XPS sheets do not align to the joins between plywood sheets.
A good way to do this is to think of the two layers – XPS board and plywood – like two layers of bricks. The ends of the bricks never really finish in the same place across 2 laters, they are skewed so that the joins never align between the different layers.
We took this extra measure of having the joins in different places because I thought that by having both the plywood and the XPS board sheet joins at the same place would cause the floor to move underfoot. Even if this was slight, it could be the difference between a smooth vinyl floor, and one that has an annoying ridge in it, that you can’t help but see and feel underfoot everyday.
- Copy the outline of the XPS board to your Vinyl flooring.
We used one continuous vinyl sheet for our flooring. We used sheets over vinyl floorboards, as the floorboards can have a tendency to expand and shrink depending on the climate and temperature we are travelling through. This means the floorboards can split, creating gaps between the boards. Also, a single continuous sheet is much better for protecting the underlying plywood from liquid accidents.
Copy the outline of your XPS board onto the vinyl layer. Make sure to leave at least 2 inches extra of vinyl around the outline of the template. This is because you want the vinyl layer to sit as closely to the walls and wheel arches as possible. You’d much rather have too much than too little. Always easier to simply cut the excess off, which we will do in a later step.
- Glue the XPS board to the van floor.
We glued the XPS board to the van floor using Sikaflex Pro. We applied Sikaflex to all of the ridges the XPS board would come into contact with and then lay the XPS sheets down in position. We then used anything we could get our hands on to weigh the boards down overnight. These objects included gym weights, an old battery, tool box, and luggage containers stuffed with heavy things.
- Now cut your plywood sheeting.
You should have drawn the outline of your XPS layer onto the plywood sheets, taking into consideration the fact that you don’t want the joins of your XPS board to align with the joins of your plywood flooring. You want them to be in different places (think 2 layers of bricks and how the joins between the layers of bricks don’t align).
- Treat your plywood for mold.
Some plywood sheeting comes pre-treated for mold which is great. But, if it doesn’t then it is really worth thinking about treating your plywood underfloor. In reality it would be pretty hard for moisture to get into the plywood flooring once your vinyl layer is installed, especially if you have also installed an insulative layer underneath the plywood. But, stranger things have happened, and this one preventative measure now could ensure a trouble free lifetime for your van floor.
Sealing the wood with a mold prevention spray and then giving it a once over with a paint primer would be the best way to ensure no mold troubles down the line.
It is worth noting that we did not do this, as we thought the XPS underlayer and the vinyl overlayer were protection enough. In hindsight, if I was to do it again, I would protect the floor with a mold prevention spray + primer combo. It would be a little extra work, but worth it for the pleasure of knowing mold simply won’t grow.
- Glue your plywood sheeting down.
We simply applied sikaflex adhesive to the XPS board and then lowered to plywood into place. Once all three sheets of plywood were in place, we again rounded up any heavy object that we could find to add downward pressure to the plywood, to make sure that it bonded well and that it didn’t warp in any places.
NOTE – It is worth adding a note here about the order of how you build and convert your van. We stopped here on the floor installation process for a little while as we still had so many other things to do in the van such as cut and install windows, roof fans and complete the wiring. This meant that if we had continued to prepare the floor and install the vinyl sheeting, the chances were very high that it would get damaged during construction of the rest of the van.
So, it is worth taking the time to think about the order in which you want to do things. And it is worth leaving the final preparation of the plywood, and installation of your vinyl sheeting as late in the build process as you possibly can.
- Sand and prepare the plywood flooring.
Now it is time to get the plywood ready for your layer of Vinyl.
We used grade C plywood for our flooring. The good stuff was just too expensive! The tradeoff to this was that I had to put a lot more effort into preparing the floor than I would have liked to.
We used wood putty to fill in any imperfections in the surface of the vinyl, and to smooth the joins between the sheets of plywood. Once we had filled in all of the surface imperfections. I sanded the whole surface so that it was smooth and even. Then it was finally ready for the Vinyl layer.
- Attach vinyl sheeting to plywood floorboards.
This is the fun bit, after this step it really feels like the inside of the van is being transformed into something very special.
Roll your vinyl up neatly so that the plywood is revealed.
Then you need to add vinyl glue to the plywood. We used a spray on vinyl adhesive that worked wonders.
It was simply a matter of following the directions on the can, which were pretty simple… Spray the van floor with the vinyl adhesive, making sure there is enough used to ensure a good coverage, without the glue bunching up in any one part.
We then rolled the vinyl out onto the floor. As we rolled it, we used a kitchen rolling pin to get all of the bubbles out. The whole process of rolling out the vinyl and rubbing the bubbles out as we went is very similar to how you would apply a screen protector for a phone.
- Trim the Vinyl sheeting edges.
In step 5 you cut the vinyl sheeting to size, making sure to add an extra 2 inches the whole way around. Now it is time to trim it down to a perfectly snug fit.
Slowly make your way around the edge of the flooring, trimming the vinyl where you think it needs it. You want the vinyl to completely cover the plywood underfloor. The vinyl should be snug right up against the wheel arches too.
- Sit back and admire your hard work!
Having the vinyl flooring in place was the first real point of our van build where I felt like we were really making progress. It changed the whole look of the van, and people could really start to get a sense of how the van was going to look when we were done.
So… would we insulate the van floor if we were to do our build all over again?
Drum roll please…. shock horror – if we decided to do our build all over again, I’m not sure that I would go through the effort of insulating the floor like we did. I’m not sure the cost of money and time was worth it frankly.
Plus, if we didn’t install the underfloor insulation, then we would have gotten an extra 25mm/1in (width of insulation) of head height in the van. This doesn’t sound like much, but actually I think it would be so much more noticeable and would impact the van internals in a much more positive way than having the insulation under the floor.
Food for thought.
Epic Insulation Guide Conclusion
The topic of insulation can be a total rabbit hole, and you can end up more confused than when you started. We really hope this epic guide helped you out with your own van build journey!