Modern building insulation comes with a challenging set of requirements. It must provide its essential function – to minimise heat transfer, keeping us warm in winter and cool in summer – but also be non-toxic and fire resistant. And, with net zero on everyone’s minds, insulation materials must deliver reduced carbon emissions too.
But, before we consider how to reduce carbon emissions arising from the built environment, we must first understand their origin.
Carbon costs
The built environment is responsible for roughly 40% of global carbon emissions. With around 28% of emissions resulting from the day-to-day use of a building, e.g. heating, cooling and lighting. This is known as operational carbon. Now, of course, equipping a building with highly efficient insulation will reduce operational carbon by minimising heat transfer to/from the outside environment. But what about that remaining 12%? What’s that “hidden” carbon cost?
The answer is embodied carbon. This refers to the carbon emissions associated with the materials and construction processes throughout the building lifecycle, e.g. from extraction and transportation of raw materials to manufacturing, through to repair and renovation and finally demolition and disposal.
Bringing this back to insulation, it’s clear that if we want to meet our net-zero ambitions a balance must be struck. On one hand, we must have highly efficient insulation that reduces operational carbon emissions. But, on the other hand, that shouldn’t come with a high embodied carbon cost, e.g. resulting from manufacture. Put more simply, the carbon emitted by manufacturing insulation shouldn’t outweigh the carbon reductions achieved by its use. And, as we’ll see below, there’s been some exciting developments on this.
Lava-ly stuff
Made from volcanic rock, “stone wool” (or mineral / rock wool), is certainly one of the more robust insulation products. Like a heavy-duty candy floss, stone wool is manufactured by heating volcanic rock to melting point (~1600ºC) then spinning the molten material into thin fibers followed by compressing and shaping. Sounds sweet, but it typically comes with high embodied carbon due to the fossil fuel-hungry furnaces utilised to melt the rock.
However, true to Saint-Gobain’s vision of becoming “the Worldwide leader in light and sustainable construction”, Saint-Gobain UK have taken steps to provide low-embodied carbon stone wool. Recently announcing their plans for a new multi-million pound stone wool manufacturing factory in Melton Mowbray that will utilise cutting-edge technology including all-electric furnaces powered by renewable energy. With construction due to start in early 2026 and production in the first half of 2027, this is another step towards Saint-Gobain’s goal to be a net-zero carbon business by 2050.
Wonderwool
Turning to another, decidedly fluffier, source of wool – sheep. The cost of sheep shearing traditionally outweighs the profits that a farmer receives for a bale of wool. Accordingly, sheep’s wool has been viewed as a net loss product of the farming industry. But this may be set to change following the trailblazing work of Wull Technologies (a collaboration between Vector Labs and Wool Insulation Wales).
Harnessing its natural insulative and fire-retardant properties, Wull Technologies have created a rigid insulation panel made from sheep’s wool. The panels – known as LAMDA (see what they did there?) – are manufactured from Welsh mountain sheep wool using a patent-pending green chemistry process that avoids plastic additives. And, following a recent boost in funding of £300k, Wull Technologies are set to scale up production and commercialisation of LAMDA.
Magic mushrooms
The thought of mushrooms in the walls would typically send a chill down any property owner’s spine, but the miracle material that is “mycelium”– and its use as a sustainable construction material – is a different matter altogether.
Mycelium is the root structure of mushrooms and has been used across many types of industry such as packaging, food, beauty products, foam and leather (see our Forward Feature “Mycelium, a natural wonder”, which describes some of the pioneering work by biomaterials company Ecovative).
Lightweight building insulation is another application of mycelium technology. Here mycelium is grown on waste biomass (e.g. sawdust) so that its fine, hairlike roots spread through the biomass, binding it together to form a solid, cohesive structure. Once the growth stage is complete the material is dried to stop any further growth and compressed to form a porous panel or brick.
Insulating the future
Populations are on the rise. Coupled with diminishing resources, it’s clear why sustainable construction is becoming ever more important. Eco-friendly insulation is one aspect of reducing the impact of the built environment on the natural world and the innovations above are just a snapshot of the progress being made on this front.
Watch this space for more blogs on recent advances in sustainable construction.
