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Your camper van insulation and ventilation is integral to the comfort level of your van life. A well ventilated van will help remove hot air, cooking smells and water vapour so will smell fresh.
A well insulated van will be warm and cosy in the cold and cool in the heat. Insulation and ventilation work hand in hand so consider both before you start your installation.
This post will guide you through all you need to know about camper van insulation and ventilation to help you in your own conversion.
Why is ventilation in your camper van important?
Condensation is a camper van’s enemy because it leads to rust.
Cooking, wet areas and even people breathing in the camper van create water vapour. With so many potential sources, an effective ventilation system will prevent a huge problem.
If there isn’t enough air flow in a camper van, condensation will build up and cause damp, mould and rust. Avoid condensation by improving airflow with a good all round ventilation system.
How much ventilation does your camper van need?
How much ventilation a camper van needs depends on a few factors so there’s no hard and fast rule, but more is definitely better than less.
The fundamental principles of ventilation remain the same.
A good ventilation system means bringing in air from outside and creating circulation.
A camper van needs enough ventilation to keep air circulating and to remove hot air, water vapour and pollutants.
The more people using the camper van, the greater the ventilation system needed.
Because cold air sinks, hot air gathers at the ceiling of the camper. So roof vents are perfect to expel air from the camper van. Place vents to bring fresh air in lower down on the camper van walls or floor.
What type of ventilation is best for my camper van?
The most basic type of ventilation for a camper van is to open the doors and windows. It’s a low cost but an incomplete approach.
During the winter months, or when stealth camping in a city, it’s not practical to keep your windows and doors open.
We’ve all been camping on a wet cold day. With closed doors and the heating on full blast, the windows steam up, right?
That condensation is also forming on the cold metal walls inside your van and will lead to rust.
Ventilation, the circulation of air, helps prevent this.
The important thing is to have enough movement of air into and out of the camper van to get rid of any lingering water vapour.
So what options do you have to ventilate your camper van?
Wind deflectors for your windows
You can gain a little security by installing wind deflectors to the side windows so you can leave them open a little at night.
Every bit of fresh air intake counts when it comes to ventilating a camper van.
Louvred air vents
A few louvred air vents fitted in strategic positions in the walls of your camper van will give a constant fresh air intake.
You’ll need to cut holes in the side of the van where you want to fit the vents but the products are low cost.
Make sure to fit fly screens behind each vent to stop unwanted bugs entering your camper van.
Wind powered roof vent
These wind powered roof vents are small so ideal for ribbed roofs such as those on a Sprinter van.
Powered only by the wind, they won’t drain your batteries and pick up quite a speed whilst driving.
The extraction rates can get quite high so they’re more effective than the louvred air vents.
Pop top roof vents
We used to drive with them open so we know they’re strong and robust. Again, you’ll need to cut holes in the camper van to fit these vents.
Because our Sprinter van Baloo was a minibus in a previous life, she had a factory fitted extractor fan already installed at the rear end of the living quarters.
It has one speed, is noisy and only worked when the engine was running. So we changed the power supply so it now runs from the house battery.
To keep our living space well ventilated without leaving doors open we needed another vent fan.
We fitted an additional multi speed, temperature sensor fan to the front end of the living area.
It’s fitted with a 12v motor and can rotate in either direction so air is either expelled or drawn. It’s not unlike a Fan-tastic Fan or Maxxfan but this one is from Fiamma.
It runs off our solar power which we installed before fitting the vent or sound proofing.
Ideally you need to plan all this before you start on your build, or work out how to retrofit the electrical circuits.
Essential reading: how to plan your camper van conversion
Why is insulation in your camper van important?
Base vehicles, ripe for conversion, tend to have little or no insulation installed. It may have started life as a courier van or something of the like.
It never needed to be warm and cosy because it was never intended as a home. Now we want to turn our van into a comfortable camper van.
So how do we turn a metal shell into a home to keep us warm in the cold and cool in the heat?
With decent insulation, combined with good ventilation and sound proofing, can create an environment anyone would be proud to call home.
Why sound proofing?
Sound proofing is a nice to have. An empty panel van is like a tin can, rattling and amplifying road noise.
Insulation will deaden this sound in the main. A lot of people also lay sound proof pads on the wheel arches and side panels before laying the insulation.
We fitted them, but I have no idea how effective they are.
We dove Baloo when she was a minibus and it was not significantly noisy. When she was complete stripped inside, she sounded like a tin can!
Once the soundproofing, insulation and carpeting was finished she was much quieter when driven.
I don’t know how much of a difference it’d make without the sound proofing in all honesty, but we’re happy with her as she is.
We used Noico 80 mil 36 sq ft car sound deadening mat. It has adhesive one side and a reflective coating on the other.
Stick the mats over the wheel arches and in the middle of all the side panels.
The theory being it will reduce panel vibration and hence noise. They also add to the insulation.
Sound proofing isn’t cheap and with everything else on the internet, for every person to swear by it, there’s plenty more who have the opposite opinion.
If you’re trying to keep your budget down, I think it’s safe to give it a miss.
How much insulation does your camper van need?
How much insulation you need depends on where you intend to take your van. You’ll need better thermal performance if you want to live in your van during cold winter months.
The primary aim of insulating your camper van is to reduce heat loss in cold weather and to keep the inside cool when it’s hot outside.
What type of insulation is best for my camper van?
A nightmare of a question! You only have to google it and you’ll find a multitude of answers, everyone with an opinion on what is right and wrong and yet all inconsistent.
How, or rather where, you intend to travel is something to consider.
The climate you plan to spend most of your time will make a difference to how much insulation you need.
We’re from the UK and converted our camper to travel around South America initially. We knew we’d travel in cold, high altitude conditions of the high Andes as well as in the heat and humidity of the Amazon.
But these are extremes and most of our time would be (and indeed is), spent in more moderate climates.
Too much insulation, while great for keeping the heat out for longer, is also terrific ate keeping it in too. So while chilly nights would be cosy, we’d melt in the heat of the jungle.
It’s all a bit of a balancing act.
During our van build, we wanted to keep our all round windows. There’s no point travelling the world if we can’t look out on our ever changing garden.
However, glass is a good conductor for heat but not so good for insulation. We needed curtains, not just for privacy but to insulate the glass too.
When it’s cold, we leave the double lined curtains open to get the heat from the sun in during the day and close them at night.
In hot sunny places, we close the curtains during the day and open them at night to help dissipate the residual day heat.
With too much insulation the heat doesn’t disappear. And in cold climes it takes a while for the sun to do its job in the morning.
So what is the right thickness and type of insulation
It drove us mad when we started to research how we would insulate Baloo. So we’re not going to even try to tell you what’s right or wrong.
It’s safe to say the colder the climate the thicker the insulation tends to be. Think of those refrigerated cargo box vans.
But we’re not planning to live in a mobile igloo, so you need to decide how deep you will insulate based on where you intend to travel in the future.
R-Values and heat value per inch
A lot of insulation materials have an associated R-Value to indicate the efficiency of that material in preventing heat loss or heat absorption under test conditions.
The test measures for heat conduction i.e. how well heat passes through the material.
In simple terms imagine a pan on a stove. If the handle has a low R-value then it gets as hot as the pan base because the heat is conducted into the handle.
With a higher R-value, the pan handle remains cool(er) to the touch.
For temperate climates the recommended level of R-value insulation is R30 for a house loft.
As a general rule of thumb, that’s around 8 -16 inches depth of loft insulation depending on the R-value.
We wanted to maximise the internal space inside the van, and we can’t afford to give away that much space.
Our advice is to go with the maximum R-value you can afford both financially and space wise.
OK so how thick do I go with my insulation?
How a campervan or RV conversion is used and where is unique to its owner. The variables are incalculable.
We have visited most climates in our van and we know our choices are a compromise.
It’s probably not ideal for the depths of a Canadian winter and too heat retentive in the hot humid Amazon. But on balance, our spec works for us.
So no prescription we are sorry to say.
Instead, here’s a list of the materials you can use to insulate your camper conversion. When deciding what combination of materials to use in your own conversion, consider your ventilation at the same time.
Avoiding and managing condensation is critical in maintaining a pleasant home.
Reflectix foil wrap
This material is like silver bubble wrap. Because it’s a radiant barrier, Reflectix is often used as sun shade on the inside of camper van windows.
There’s a lot of debate on how effective this stuff is as an insulator on the camper van walls though.
It is most effective with an air gap so this needs to consideration before adding the next layer of insulation.
The inside of most camper van walls consist of large flat(ish) panels and lots of smaller spaces too. Reflectix is easy enough to install on the larger panel areas with adhesive tape or spray.
We did not use this material.
Foam board insulation with rigid Panels
Polystyrene and styrofoam boards are low cost and quick and easy to fit to the large panel in the camper van. We used 25mm on the roof of our Sprinter van conversion and 40mm thick board in the walls.
In Mowgli our Unimog camper, we had 40mm boards all round. We used the boards that are foil lined on both sides as it gives a slight improvement on the thermal protection.
Cut the foam board insulation to neatly fit into the ridge areas of the walls. You can hold it in place with tape or glue.
A word of advice, it’d be easy to make the boards a tight fit between the ribs. There’s a risk once you have covered everything the boards might annoyingly squeak when you drive.
There is a similar risk of stacking them too loose.
Spray Foam insulation
It is claimed this stuff has the highest R-value rating and so the most efficient insulation material. But it’s messy to apply and can be expensive if professionally done.
We avoided it.
I once heard of a chap who spent 9 months waiting for his brand new sprinter to roll off the production line.
He immediately got it insulated by a professional spray foam insulation firm. Later that day he shared a load of pictures of his destroyed panels on his shiny new van.
It seems the spray foam used by some firms to fill house cavities generates immense heat when applied and expands.
I don’t know if the van had interior panels fitted and they filled the cavities or just spray onto the interior panels.
Either way the panels van warped and he wasn’t a happy bunny.
I had my own bad experience using the cans of spray foam insulation I got from a local DIY hardware store. I tried to fill the gaps around our home front door. 20 minutes to apply and 2 days to clean up the expanded bright green gunge on the brick work and door frames.
It might be useful to fill the gaps in the panel ridge frames, but once in its not coming out. Ever.
So this prevents any future opportunity to run cables or service pipes. To be honest it’s just too messy for me.
We used rock wool for those awkward gaps.
This is the flexible rolls of material we find in many lofts. The advantage of loft insulation is you can squeeze it into all the nooks and crannies you can’t fit the boards into. Again, the choice of materials is wide.
You can choose fibreglass, recycled plastic, recycled denim or wool. They all have different properties and R-value.
Wool tends to have the highest R-value (thermal protection). Fibreglass is nasty stuff to work with because it makes you itch and you need to wear a mask and gloves to install it.
It doesn’t handle moisture too well either. We used the recycled plastic bottle material in our Sprinter van conversion.
Many camper conversions add a vapour barrier over the top of the insulation and before lining the walls and ceiling. This will prevent any water vapour not ventilated making it’s way to the metal and eroding it over time.
Many converted camper vans use a combination of insulation materials. In our Sprinter van Baloo, we’ve used rigid panels with recycled plastic bottle loft insulation.
We tried to refit the original headliner as it was also insulated with wool and a vapour barrier too. That didn’t work out too well unfortunately. I ended up making a roof liner with thin laminate board and carpet.
And we chose not to include a vapour barrier this when we place the insulation board and rock wool up there. We’ve not used a vapour barrier on the walls either.
As a result we always keep the van fully ventilated even when dry stored.
How to insulate your van walls and van ceiling
With so many material choices we went for the simple approach.
If you’ve planned where all your cables and pipes are going to run and have fitted and tested all your electrics and service pipes, then you’re ready to begin insulation.
Attach those sticky sound proof pads to the middle of each panel space if you decided to have them.
Cut the foam board so they loosely slot into the space between the wall ribs.
Sometimes getting the board behind the ribs is a challenge so you might need to cut several pieces. Stick them in place using tape or glue.
Try not to have separate board edges hard up against each other or any other hard edges. There is a chance they will annoyingly squeak as they rub together as you drive along.
Fill the gaps with rock wool, and use tape to hold them in place until the top or interior wall covering is in place.
We used 3mm hardboard with car carpet coverings as our top layer. Some people use wood or aluminium backed formica as their top cover and interior finish.
If you choose to fit a vapour barrier then the time to fit it is after filling and taping the insulation board and rock wool, but before you fit the interior wall.
When you fit the boards and rock wool make sure not to crimp any pipes or cables. Make sure those cables and pipes still run and terminate in the places you wanted them.
Useful planning tip | avoid having any joints or connections in any pipes or cables hidden within the insulation layer. They’ll be quite tricky to access if you need to fix anything in the future. Plan all you connections outside of the insulated area.
How to insulate a van floor
On some winter days when I step out of bed in my bare feet, I wish I’d insulated our camper van floor much better. It’s cold and I need to reach for my flip flops.
We installed10mm hardboard and Karndean floor tiles on top of the factory fitted 1” laminated wood floor that had a heavy duty linoleum top layer.
I thought this would be enough insulation for the floor. Seems not for those occasional mornings.
If I were to go back and insulate the floor again, I’d build a 1” raised floor on battens and fill the air gap with rock wool.
This raised floor would need to be well structured to prevent the top floor flexing or sagging as you walked on it. It’d also reduce the interior height and add a bit more weight to the build.
For now, I’ll keep my socks on.
Your camper van insulation and ventilation work together to help provide a clean, warm and dry home. Because you’ll only install the insulation once, our advice is to do it well.
Have plenty of ventilation and the structure of your camper van will give you many, many comfortable van life years.