Comparing Insulation Materials – Envirofoil v Wool

When choosing an insulation material for your cold chain packaging, there are several factors to consider. With so many options and opinions on the topic of packaging we provide an unbiased view on products, giving you facts and reality to make sustainability your decision.

All products and materials have their pros and cons so understanding your business goals and what your customers are looking for helps when considering different options. In this blog we compare two of our popular insulation options, Envirofoil and Sheep’s Wool across the important factors of performance, sustainability, and disposal.

Performance & Characteristics

Envirofoil Liners/Pouches

Envirofoil is made using a combination of an internal bubble layer and a reflective outer layer which work together to provide reliable temperature control. Envirofoil pouches have been a staple in the cool-chain packaging industry, due to the known characteristic of foil to reflect heat and the bubble providing an air gap between the product and exterior temperatures.

The performance of Envirofoil is linked to the bubble size, for example a 20mm bubble will perform better that 10mm bubble, as the 20mm bubble provides a larger air pocket giving it better the insulation. The outer silver layer not only reflects radiant heat but also minimises the transfer of convective heat across the pouch surface, acting in conjunction with the bubble liner, to further the thermal performance. With the pouches featuring an adhesive flap, the chilled air is kept tightly sealed and air flow in and out of the package is inhibited.

Wool Liners

On the other hand, Wool, as a natural insulating material, performs extremely well when utilised in cool-chain packaging. Wool liners are a promising alternative to Polystyrene and has been proven to match or exceed the thermal performance of this traditional material. Wool is hydroscopic in nature, and therefore absorbs excess moisture, supports structural integrity of the package, and provides mechanical cushioning during transit.  The Wool Liner can be wrapped in both biodegradable and MPDE film options.

When the wool fibres are closely woven, there is better capture of air inside the carton, insulating the chilled product inside. The performance of wool is highly dependent on the density and gsm (grams per square meter), as the higher the gsm, the better performance. For any standard carton, 650gsm wool liners are recommended, but for transit times greater than 48 hours, 1600gsm is recommended.



As a product with foil and plastic components, Envirofoil may at first be considered unsustainable to the public. However, Envirofoil has a smaller environmental impact than a wool liner with recyclable film. As Envirofoil is made up primarily of one component, MDPE film, this is easy disposed of in a soft plastics recycling bin. With a one-step method to recycling, the recycling of Envirofoil is more realistic and easier for the consumer to complete and can be an important aspect to consider when discussing sustainability. However, if not disposed of correctly, such as in a kerbside bin, the impact of the Envirofoil on the environment is the same as a plastic bag, as it can take thousands of years to breakdown while in landfill or can damage recycling facility machinery.

Wool Liners

As a natural resource, Wool Liners, with both a plastic and biodegradable film, are perceived positively in terms of sustainability amongst end-consumers and businesses alike. This is not an incorrect perception, as a zero-landfill cool-chain material, however this may be exaggerated as it is not the easiest product to dispose of. Creating Wool Liners reutilises wool offcuts that would have otherwise been thrown out but is repurposed into insulation material for the cool-chain industry. As there is no need for raw material to be used, this insulation material protects natural resources, and means less energy is used to create this product.

When wrapped in biodegradable film, the Wool Liner naturally biodegrades within 18 months, and leeches several valuable nutrients back into the soil, and is the perfect additive to a garden bed or compost bin. The alternative, the Wool Liner with an MPDE film can also be composted but must first be removed from the film sleeve. The film is still recyclable, so the environmental impact of this product is low, if handled correctly.

Realistically, a very low percentage of consumers will dispose of the wool liners in the correct manner, due to the number of steps in disposing or lack of education around the material, therefore most will end up in the kerbside rubbish. If not recycled correctly, the MDPE film will take 1000’s of years to break down, alike to the Envirofoil, which additionally slows down the biodegradation of the wool. However, the benefit of the wool liners with the biodegradable film is that even if they are not recycled correctly, the wool liner will still biodegrade in landfill.




Thermogard’s Envirofoil is manufactured locally in all regions, close to our customers. Our Envirofoil is commonly reused by consumers and home delivery companies with return logistics will collect and reuse the pouch in their business process.

Envirofoil pouches are easy to recycle, as they are considered ‘soft plastics. Once they are clean and dry, they can be dropped off at a soft plastics recycling bin at your customers nearest participating supermarket for no charge. From here the soft plastics will be repurposed into other products. Find out about soft plastics recycling on a customer or commercial level here.

Wool Liners

As discussed, the Wool Liners come in two options – biodegradable film and MPDE film. For the fully biodegradable option disposal is easy, simply put the entire liner in your garden or bin and the entire product will compost. For liners with the MPDE film, the film must first be removed before the wool inner is disposed of. The film must then be recycled separately at a soft plastics recycling depot or soft plastics bin at your nearest supermarket. Find out about soft plastics recycling on a customer or commercial level here.



Ultimately, as we often conclude, no one material is inherently better than the other, as this depends on what is best for your business goals and requirements. Both Wool and Envirofoil are viable options for cool-chain packaging insulation, hence their popularity, but they are only two of many options we have at Thermogard. If you have any questions or would like to discuss these insulation materials further, get in touch with us today.

Speak to the thermogard team about your needs

Connect with Thermogard for cool chain insights, advice from our in-house experts, and information on market leading innovations. We're not just about solutions; we provide data-driven insights, tailored consultation, and a global network to ensure your cool chain success.