Why is van insulation important?

Cargo van insulation is really important in order to moderate the temperature within your van. Typical cargo van conversions will use a panel van as a base vehicle, but the thin metal walls will very easily transfer heat and equalise to external temperatures. If you’re in extremely hot or cold climates this could mean a lot of discomfort. Van insulation will ensure that the temperature equalisation proces is slowed way down and you stay comfortable in your tiny home!

This epic insulation guide includes all the research we did when converting Maeve into our all-year-round adventure vehicle.

What types of insulation can you use in a cargo van?

You’ll come across quite a few options in choosing the best van insulation material for you. Some of these are the same as you’ll find in many standard homes. Others, however, are more bespoke and harder to come by, and therefore far costlier to your wallet but potentially a much better insulation investment.

We recommend considering the following when choosing your van insulation material:

• Toxicity – This was a big deal for us, as we didn’t want any particulates or gases contaminating our small living space. We were running away from the city because of air pollution so didn’t want any respiratory aggravators or health risks.
• High R-value – As you’ll need to maximise the space in your van, it’s important to use a material which has a high insulating value per inch.
• Moisture resistance – In a small space you’ll generate moisture from cooking, showers, breathing etc. You’ll want to use insulation which is moisture resistant to stop any mould growth or take precautions to ensure no moisture can access your insulation using a vapour barrier.
• Cost – We learnt that converting a van can become very expensive very quickly. Plan ahead to get products which do the job well but don’t cost the earth.
• Eco friendliness – Some insulation options are very eco friendly, as they are made from recycled plastics or old clothes. Others not so much. If you want to be more eco conscious this is something to consider, and there are a variety of options now available. More on this further on!

Polyisocyanurate (PIR) van insulation

In the US this is commonly known by the primary manufacturer of the product, Celotex. Within the US, it’s most frequently called foam board insulation. PIR insulation is an excellent choice because it is lightweight, moisture resistant, affordable, non-toxic and fire resistant.

PIR boards come in a range of thicknesses and are excellent choices for insulating the ceiling and floor of a van conversion. The only danger is from inhaling the dust created when cutting the boards. We found using a sharp knife created a very clean cut with minimal dust, but we were also careful to use masks when cutting. Either side of PIR insulation is usually a reflective barrier which helps keep radiant heat within your van.

Reflectix – Cargovan foil insulation

This material is very widely used in van conversions, but often incorrectly! It’s a thin bubble wrap with a reflective coating and holds a very low R value. Reflectix is excellent at reflecting radiant heat but it is not efficient at stopping the transfer of heat.

The common mistake is adhering Reflectix straight onto the metal of a van and then adding another layer on top. Heat passes straight through the reflectix from contact with the metal through conduction and makes it totally ineffective.

Reflectix is great when being used as a window blind as it reflects heat back. To make it more attractive, we covered it in thick cloth. It’s also moisture resistant and can be used as a vapour barrier which is how we used this material in our van build.

Polystyrene van insulation

What is the difference between extruded and expanded polystyrene?

Extruded polystyrene is arguably one of the most environmentally unfriendly products in this list. This is due to the manufacturing methods using hydrofluorocarbons via an extrusion process and polystyrene polymer.

Expanded polystyrene is manufactured without these gases as by-products and has a far more air gaps within its structure. The trade off is that this renders it slightly less moisture resistant. Both types of polystyrene are similar in structure to PIR insulation which comes in a range of thicknesses. The major health consideration is the inhalation of particles from cutting or from abrasion within your van.

It has a good R value slightly less than that of PIR but both types are slightly cheaper. It’s far more resistant to compression than PIR which makes it a popular choice for use in flooring. It is however far less flame resistant and when it combusts gives off styrene gas which can causes CNS damage.

Closed cell spray foam

This is the most effective insulating material on the list and if installed correctly can completely shield the metal on your panel van from interior moisture as it is impermeable. It’s often recommended to seek professional help when installing as the foam expands over time and over-spraying can damage your van through extrusion.

This is also one of the most permanent options. Removing this stuff is a nightmare so make sure you’ve planned out your entire setup well and have left conduit with enough room to thread any extra cables/pipes you require. You can buy disposable spray foam cans from building suppliers which are great for filling gaps and ribs within the van walls or complete kits from online sellers.

Fibreglass van insulation

Fibreglass is our least favourite insulation but also the cheapest. Fibreglass has been used for many years, and although it is an effective insulator, our concerns come from its toxicity. Contact with skin will result in a rash and it naturally sheds very small fibres, which will be exaggerated through vibration in the van. If inhaled, these can cause respiratory damage.

Another downfall is that it is not moisture resistant and will mould if it gets wet. If you use fibreglass, wear the necessary protection when installing it and make sure it’s completely sealed up with a vapour barrier after installation.

Rock wool/Mineral wool van insulation

Mineral wool is perhaps one of the most common household insulation materials within the US. It’s slightly more effective than fibreglass and slightly less toxic. It still has a tendency to shatter into shards which are an irritant so using the correct protection when installing is absolutely necessary.