As the cost of purpose-built motorhomes continues to rise, more and more people are discovering the flexibility and affordability of converting a van into their own campervan.
When converting, one of the most important decisions you'll make is choosing the right insulation. Good insulation keeps your van warmer in winter, cooler in summer, reduces condensation, improves energy efficiency and even helps minimise road noise.
In this guide, we'll answer the most common questions about insulating a van conversion and explain which insulation materials work best.
Why is insulation important in a van conversion?
Insulating a campervan provides several key benefits:
- Maintains a comfortable temperature year-round
- Reduces heat loss in winter
- Helps prevent overheating during summer
- Controls condensation and moisture
- Minimises the risk of damp and mould
- Reduces road and external noise
- Improves the efficiency of your heating or cooling system
Without proper insulation, metal van panels quickly transfer heat and cold, making the interior uncomfortable and increasing condensation.
How do you insulate a campervan properly?
For the best results, insulation should be installed as continuously as possible across the van
Avoid leaving gaps between insulation pieces, as these create thermal bridges where heat can easily escape. These cold spots also increase the likelihood of condensation forming on the metal bodywork.
For most van conversions, it's recommended to:
- Fill cavities with flexible insulation
- Insulate larger flat panels with rigid insulation where appropriate
- Install a vapour control layer on the warm (interior) side of the insulation
- Seal gaps carefully around windows, doors and joints
Many van conversions achieve the best results by using a combination of insulation types rather than relying on just one product.
How do you prevent condensation in a campervan?
Condensation is one of the biggest challenges in campervan conversions.
Moisture comes from:
- Cooking
- Breathing
- Wet clothing
- Water entering through doors, windows or roof fittings
To reduce condensation:
- Choose moisture-resistant insulation where possible
- Minimise gaps in the insulation layer
- Install a vapour control layer correctly
- Ensure adequate ventilation throughout the van
- Repair any water ingress around roofs, windows or doors promptly
Proper insulation and ventilation work together to keep your campervan dry and comfortable.
What is the best insulation for a van conversion?
The best insulation depends on where it will be installed and your priorities, such as thermal performance, sustainability or ease of installation.
Sheep's Wool Insulation
Sheep's wool insulation is one of the most popular natural options for campervan conversions.
Benefits
- Excellent thermal performance
- Naturally regulates moisture
- Flexible enough for awkward cavities
- Helps reduce condensation
- Good acoustic insulation
- Soft, non-irritant and easy to install
- Available in rolls and slabs
Sheep's wool is particularly well suited for filling curved body panels and hard-to-reach areas where rigid boards won't fit easily.
Recycled Plastic Insulation
Recycled plastic insulation offers a practical alternative that is lightweight and easy to work with.
Benefits
- Made from recycled plastic fibres
- Soft and non-irritant
- Flexible and compressible
- Cost-effective
- Easy to cut and install
-
Good thermal and acoustic performance
Its flexibility makes it ideal for irregular spaces throughout the van.
PIR Insulation Boards
PIR boards offer one of the highest thermal performances available.
Benefits
- Excellent insulation value
- Thin profile saves interior space
- Moisture resistant
- Ideal for flat surfaces
- Suitable for floors, walls and ceilings
PIR boards work best on larger flat areas where they can be cut accurately to fit.
Note: PIR boards are not structural and should not be subjected to point loads without an appropriate floor construction above them.
Reflective Foil or Bubble Insulation
Reflective insulation products are often used alongside other insulation materials.
Benefits
- Lightweight and flexible
- Waterproof
- Reflects radiant heat
- Easy to cut and shape
- Useful for tight spaces
- Ideal for insulated window covers
Reflective insulation is particularly effective for window shades, helping keep heat inside during winter and reducing solar gain in summer.
Can you combine different insulation materials?
Yes. In fact, many professional van converters use multiple insulation products throughout the vehicle.
For example:
- Flexible insulation in body cavities
- PIR boards on flat walls and floors
- Reflective insulation around windows
- Vapour control layer to manage moisture
Using the right material in each area creates a more efficient insulation system.
Natural Options
Thermafleece CosyWool or Supasoft – Flexible, easy-to-install options that are ideal for filling awkward cavities and irregular spaces within a van conversion. CosyWool offers excellent thermal and acoustic performance, while Supasoft provides a lightweight, cost-effective solution made from recycled plastic fibres.
Limited Space
Spacetherm / Aerogel Blanket – An excellent choice where space is limited. Aerogel insulation offers exceptionally high thermal performance in a very thin layer, with options available from as little as 5mm thick. Its flexibility also makes it easy to cut, shape and adhere to surfaces, making it particularly useful for areas where conventional insulation would be too bulky.
Frequently Asked Questions
What thickness insulation should I use in a campervan?
The ideal thickness depends on the available space and your climate. Preferably, you want to put in as thick insulation as the space allows. Flexible insulation is commonly available from 5mm to 100mm, while PIR boards range from 15mm to 200mm.
Does insulation reduce campervan noise?
Yes. Flexible insulation materials such as sheep's wool and recycled plastic insulation help absorb sound and reduce road noise.
Do I need a vapour control layer?
In most campervan conversions, installing a vapour control layer on the warm side of the insulation helps reduce condensation within the wall construction.
Is sheep's wool good for van insulation?
Yes. Sheep's wool naturally regulates moisture, offers excellent thermal performance and is easy to install in irregular-shaped cavities.
What is the most space-efficient insulation?
PIR insulation boards provide very high thermal performance while taking up minimal space, making them ideal where every millimetre counts.
Need Help Choosing Campervan Insulation?
Every van conversion is different, and selecting the right insulation depends on your layout, available space and intended use.
Our experienced team can help you choose the best insulation products for your campervan, motorhome or van conversion project, ensuring you achieve excellent thermal performance while reducing condensation and improving comfort all year round. Get in touch today for a no-obligation quote.
