# Mycelium-Based Thermal Insulation for Domestic Cooling Footprint Reduction: A Review
## 7 Environmental Impact of Mycelium Thermal Insulation  
Mycelium insulation represents an innovative biomaterial achieved by cultivating fungal hyphae on organic substrates, notably agricultural and forestry residues. Diverging from conventional insulation materials like mineral wool, expanded polystyrene, and polyurethane foam, which stem from non-renewable resources and exhibit resistance to biodegradation, mycelium insulation distinguishes itself by its complete biodegradability. Integrating biodegradable materials holds the potential to curtail the environmental repercussions linked to waste generation and disposal while fostering nutrient cycling and enhancing soil vitality. Findings indicate that mycelium, functioning as a binding agent, displays an inclination towards initial decomposition. Evidently, a notable mass reduction of 43% was observed in inert samples comprising _Ganderma resinaceum_ fungal strain and hemp fibers after sixteen weeks. Nonetheless, the pace of disintegration in this context hinged upon a constellation of factors encompassing material constitution, manufacturing technique, and the intricacies of the degradation process, including equipment, materials, and environmental attributes. Noteworthy research affirms that mycelium insulation can undergo degradation within weeks or months, given favorable circumstances [78]. In contrast, conventional insulation materials tend to endure within the ecosystem for extended periods, amassing in landfills and aquatic habitats, thereby precipitating ecological harm. Furthermore, select conventional materials may contain deleterious components, such as formaldehyde, brominated flame retardants, or hydrofluorocarbons, which can leach into soil or water, thereby posing hazards to human health and wildlife. Consequently, mycelium insulation emerges as a viable, circular, and ecologically responsible alternative to existing insulation materials, underpinned by its profound biodegradability. Moreover, mycelium insulation engenders a pivotal avenue for carbon sequestration, wherein atmospheric carbon is assimilated and stored within its biomass, thereby ameliorating greenhouse gas emissions. A substantive proportion of terrestrial carbon, constituting 75%, is sequestered subterraneously. On a global scale, plant communities allocate 3.93 Gt CO\({}_{2}\)e annually to arbuscular mycorrhizal fungi, 9.07 Gt CO\({}_{2}\)e to ectomycorrhizal fungi, and 0.12 Gt CO\({}_{2}\)e to ericoid mycorrhizal fungi. Based on this assessment, a notable 13.12 Gt of CO\({}_{2}\)e sourced from terrestrial vegetation is temporarily attributed to the subterranean mycelium of mycorrhizal fungi each year, constituting a significant 36% of ongoing annual CO\({}_{2}\) emissions derived from fossil fuel sources [79].  
The mycelium insulation material demonstrates notably reduced embodied emission values compared to other evaluated materials. When considering CO\({}_{2}\) absorption, mycelium insulation material's initial represented emission value stands at \(-\)244 kgCO\({}_{2}\)eq/m\({}^{3}\). With decreasing energy requisites, these embodied emissions are further diminished to \(-\)298 kgCO\({}_{2}\)eq/m\({}^{3}\), establishing the mycelium insulation material as carbon negative. Conversely, the displayed emission values for EPS, XPS, Polyurethane, and Phenolic foam are 231.2 kgCO\({}_{2}\)eq/m\({}^{3}\), 271.8 kgCO\({}_{2}\)eq/m\({}^{3}\), 560.5 kgCO\({}_{2}\)eq/m\({}^{3}\), and 1136 kgCO\({}_{2}\)eq/m\({}^{3}\), respectively. Illustrated in Figure 6, the mycelium insulation material boasts the most minor emissions per cubic meter of material, consequently yielding the most minimal cumulative emission value during the production process.