Bio-retrofit: Potential of mycelium-based composites to future-proof India and Australia’s residential buildings against extreme climate events post-2040

In India and Australia, many residential buildings lack adequate thermal comfort, particularly during extreme heat events such as heatwaves. This results in indoor overheating and elevated air-conditioning (A/C) use, leading to increased energy demand for cooling. Most existing and newly built residential buildings will remain operational post-2040, necessitating retrofitting for extreme climate events in a warming world. While lower carbon retrofitting technologies are emerging, many are still carbon-intensive in manufacture and disposal, hindering net-zero goals. The emphasis on maximising the build-up area complicates external retrofitting. This study explores mycelium-based composites (MBC), an innovative biogenic material, to enhance resilience against extreme climate events in these regions post-2040. Our bio-retrofitting solution, MBC insulation, was tested using simulated models from living labs in Sydney and Vadodara under various climate scenarios via Designbuilder and EnergyPlus. Preliminary simulation results reveal a 5—21% rise in indoor temperatures in both countries, with cooling energy demands increasing 1.9—3 times due to higher outdoor temperatures. Bio-retrofits could reduce this demand by approximately 0.4—3.2%. However, this study investigated using carbon-negative MBC, derived from local biomass waste, at a larger scale to improve residential building resilience against future climate challenges; further investigations are required to reduce the anticipated cooling energy demand through passive building skin solutions.