Insulating a Camper Van Using Thermafleece Insulation FAQs

If you’re planning a camper van conversion, choosing the insulation is one of the most important steps for comfort, condensation control and sound reduction. At Celtic Sustainables, we supply Thermafleece Cosywool sheep’s wool insulation and Thermafleece Supasoft recycled polyester insulation to DIY van converters and professional campervan conversion companies across the UK. This guide answers the most common questions about insulating a camper van with Thermafleece products.

What Are The Benefits Of Using Thermafleece Insulation Products For Insulating A Camper Van?

• Excellent thermal performance: Both Thermafleece Cosywool sheep’s wool insulation and Thermafleece Supasoft recycled polyester insulation help keep your camper van warmer in winter and cooler in summer.
• Safe for confined spaces: Thermafleece insulation is non-toxic, making it a practical choice for small living spaces such as campervans, vans and motorhomes.
• Itch-free installation: The insulation is non-irritant and comfortable to handle, so it is easier to fit than many traditional insulation materials.
• Acoustic benefits: Thermafleece helps reduce road noise and improves sound comfort inside the van.
• Flexible fit: The soft, flexible rolls can be tucked into awkward cavities, corners and curved areas, helping to reduce thermal bridges where heat can escape.

Why choose Thermafleece Cosywool sheep’s wool insulation? What are the benefits?

• Sheep’s wool is hygroscopic, which means it can absorb, hold and release moisture as humidity levels change. In a camper van, this can help reduce the risk of condensation forming on cold metal bodywork. Thermafleece Cosywool can absorb a significant amount of moisture without compromising its insulating performance, making it a popular natural insulation choice for campervan conversions.

Photo credit. Kirsty and Barra @earlyadvantures

Camper Van Membranes and Vapour Barriers

Do I need a vapour control layer when insulating a camper van?

Whether to use a vapour barrier in a camper van is widely discussed across vanlife blogs, forums and conversion groups. The best approach depends on the insulation material, ventilation and how the van will be used.

Cooking, boiling kettles, drying clothes and breathing all add moisture to the air inside a van. When warm, moist air reaches cold metal bodywork, condensation will form. Good insulation, ventilation and moisture management all help reduce this risk.

Thermafleece Cosywool can buffer a certain amount of moisture, but no insulation should be expected to manage unlimited humidity. If the insulation becomes saturated, its thermal performance will be reduced and moisture may still reach the metal bodywork. Adding a suitable membrane can help control the movement of water vapour in and out of the insulated cavity.

Thermafleece recommends using a smart membrane such as the Thermofloc VSD membrane over the insulation. A smart membrane changes its state depending on humidity levels: when moisture levels are high, the pores in the material close,  limiting the amount of water vapour entering the cavity; when the humidity level drops, the pores open, allowing any trapped moisture to escape.

A fully sealed plastic vapour barrier may appear to be a simple solution, but in a van it can be difficult to achieve a perfect seal. If moisture gets behind an impermeable barrier through gaps or bodywork leaks, it can become trapped and increase the risk of corrosion.

Measuring Up - How Do I Measure A Camper Van For Insulation?

What thickness of insulation should I use in a camper van?

The best insulation thickness depends on the space available between the metal bodywork and your internal lining or cladding. You do not need to leave an air gap. Measure from the outer metal skin to the point where the lining board will be fixed; this measurement will guide the insulation thickness you need.

Can I compress camper van insulation?

If your measurement falls between two available insulation thicknesses, choose the thicker option where possible. A slightly oversized roll can create a snug fit, reduce gaps and help minimise heat loss.

While heavy compression can reduce thermal performance slightly, light compression in a van cavity is not usually a major issue. The aim is to fill the space well without leaving voids where cold spots can form.

Once you have established the thickness of insulation required, you will need to calculate how many rolls to buy. 

How do I work out how much camper van insulation I need?

To calculate the number of rolls required for your campervan conversion, measure the total area you want to insulate.

Measure each panel separately, including the roof, floor, side panels and rear doors. Multiply the width by the height of each panel to calculate the area. For example, a panel that is 2m wide and 1.5m high has an area of 3m². Add all panel areas together to get the total square metres required.

On the product page for your chosen Thermafleece insulation, select the thickness and width you need. The coverage shown in brackets tells you how many square metres one roll will cover.

Divide your total area by the roll coverage to work out how many rolls to order. For example, if your van needs 20m² of insulation and you choose a roll size with 7.41m² coverage, 20 ÷ 7.41 = 2.69. In this example, you would order 3 rolls.

Photos from K.ustom Campervan Converters

Camper Van Insulation Installation

How do I hold camper van insulation in place?

Strips of double-sided carpet tape applied to the metal bodywork can help hold the insulation in place while you fit the cladding or lining boards. Spray adhesive may also be used. Once the lining board is installed, friction will help keep the insulation secure.

Is Thermafleece insulation easy to cut?

Thermafleece Cosywool and Thermafleece Supasoft can be cut with a sharp craft knife, insulation knife or scalloped blade such as a bread knife. For smaller spaces, the insulation can also be torn into manageable pieces and fitted into awkward cavities.

Which Thermafleece Insulation Is Best For A Camper Van?

Both Thermafleece Cosywool and Thermafleece Supasoft are popular choices for camper van conversions because they offer thermal insulation, acoustic comfort and easy installation. Cosywool is ideal if you want a breathable natural sheep’s wool insulation, while Supasoft is a good option if you would prefer recycled polyester insulation. We supply both products to DIY converters and commercial camper van conversion companies, so whichever option you choose, you can be confident you are using a professional-quality insulation product.

What Have Other Campervan DIY'ers Done?

Looking for practical, eco-friendly campervan insulation ideas? Read how vanlife enthusiasts Craig, Kirsty and Barra the dog, along with self-build campervan converters Matt, Sarah and Bill the dog, approached their van insulation projects in our article Eco Campervan Conversion – Insulating your Campervan. You can also explore Rosie Sherwood’s decision-making process and learn why she chose natural insulation in our blog post Eco Campervan Conversion Using Thermafleece Cosywool with Rosie Sherwood, and discover why K.ustom Campervan Converters choose Thermafleece Supasoft.

Ready To Choose The Right Camper Van Insulation?

Browse our Thermafleece Cosywool and Thermafleece Supasoft insulation ranges online, or contact us for friendly advice before you buy. Tell us about your van, the areas you want to insulate and the thickness available, and we’ll help you choose the right insulation, roll size and membrane for your conversion. Order online for UK delivery and make your campervan warmer, quieter and more comfortable all year round.

Why Buy Your Thermafleece Camper Van Insulation From Us?

✅ Buy only what you need - We split packs so you can buy by the roll.

✅ Large, regularly replenished stock for fast delivery - Usually 1-2 working days.

✅ If you need a larger quantity, please contact us for a quote.

✅ £10 - £30 Max delivery fee for any order size to most UK postcodes.

✅ Over 200,000 rolls of Thermafleece insulation sold & delivered to date.

✅ Courier delivery tracking & pallet deliveries arranged to suit you.