Mycelium Insulation: Why 17 Fungal Species Produce Similar Thermal Performance
- Gauri Khanna
- 3 hours ago
- 3 min read
Too long to read? Go for the highlights below.
Researchers at the University of Bath tested 18 fungal strains to create mycelium-based insulation, finding all achieved thermal conductivity below 0.1 W/m·K; the threshold for effective insulation
Whilst fungal species selection influenced appearance and chemical composition, thermal performance varied only slightly, suggesting production flexibility without compromising insulation quality
Physical properties like density proved more important than chemical differences in determining heat transfer, with a positive correlation between density and thermal conductivity
The construction industry accounts for 36% of global COâ‚‚ emissions, with heating and cooling responsible for the majority of a building's operational carbon footprint. As pressure mounts to decarbonise the built environment, researchers at the University of Bath have systematically evaluated whether fungal species selection significantly affects the thermal performance of mycelium-based insulation materials.
Testing Across Species
The research team produced mycelium-based composites using 18 different fungal strains representing 17 species, all grown on hemp-shiv substrate under identical conditions. The fungi included various Ganoderma species (reishi variants), Pleurotus species (oyster mushrooms), and Trametes versicolor (turkey tail) which are all classified as selective white rot fungi that preferentially degrade lignin whilst preserving structural cellulose.
Each composite underwent rigorous thermal testing using a Heat Flow Meter according to international standards. The results proved encouraging for commercial mycelium insulation applications. All materials achieved thermal conductivity values below 0.1 W/m·K, the recognised threshold for effective insulation. Pholiota adiposa produced the lowest value at 0.0376 W/m·K, whilst Lentinus tigrinus registered the highest at 0.0451 W/m·K.
Statistical analysis confirmed these differences were significant, yet relatively modest in practical terms. This finding suggests that producers need not depend on a single optimal species, providing flexibility in sourcing and production:particularly valuable as mycelium materials scale commercially.
Physical Structure Matters Most
The researchers employed Fourier Transform Infrared Spectroscopy (FTIR) to examine chemical differences between composites made with different species. This analytical technique identifies functional groups in materials, revealing how fungi chemically modify their substrate during growth. Advanced statistical methods including Principal Component Analysis detected species-specific chemical signatures in the hemp substrate after fungal colonisation.
However, these chemical variations showed no meaningful correlation with thermal performance. The implication is clear: whilst different fungi modify hemp-shiv in distinct ways, these chemical changes exert minimal influence on heat transfer properties under the tested conditions.
Density proved more relevant. The study identified a statistically significant positive correlation between density and thermal conductivity as higher density materials conducted more heat. This aligns with fundamental physics: denser materials contain fewer insulating air pockets and more solid material capable of transferring heat. The finding suggests that optimising growth conditions to reduce density, rather than selecting specific species, may offer a more effective path to improved thermal performance.
Practical Implications
Beyond thermal measurements, the composites exhibited notable aesthetic variation. Materials produced with Laetiporus sulphureus displayed distinctive orange colouration, whilst other species yielded different textures and surface characteristics. Such diversity matters for architectural applications where visual appearance influences material acceptance.
The successful production of viable insulation from 17 species using a single substrate demonstrates the robustness of mycelium-based material technology. Hemp-shiv, an abundant byproduct of hemp processing, proved compatible with all tested species: a practical advantage for scaling production using locally available agricultural waste streams.
The research also established FTIR combined with multivariate analysis as a potential tool for classifying mycelium materials; useful for future waste management as these products reach end-of-life. Different substrate-species combinations may require distinct recycling or disposal approaches.
For the construction industry seeking sustainable insulation alternatives, the University of Bath research delivers a pragmatic message: mycelium-based insulation works across multiple fungal species, and optimising physical properties may prove more fruitful than pursuing perfect species selection. The versatility revealed by testing 17 species strengthens the case for mycelium insulation as a viable, scalable alternative to conventional materials.