Development of a Super-insulating, Aerogel-based Textile Wallpaper for the Indoor Energy Retrofit of Existing Residential Buildings

Abstract Retrofitting the residential building stock poses a major challenge for the European building sector in the coming years. It is also crucial to achieve the decarbonisation goals set by the EU's Energy Roadmap 2050. The EASEE research project, funded by the European Commission, addressed this issue by developing a holistic approach to envelope retrofitting. This paper presents an innovative technical solution developed within this research project: a lightweight, aerogel-based wallpaper that can be easily installed on the inner side of perimeter walls. The system is composed of an aerogel-impregnated textile layer, forming the insulating core, and a fabric finishing that can be easily installed and replaced thanks to a bespoke tensioning device. The development of the system is explained starting from the identification of the challenges related to the application of an insulating layer to the internal face of an existing wall. These include building physics, as well as operational aspects to reduce disturbances of users. The insulating layer, based on a textile mat impregnated with aerogel, was tested and characterised at laboratory scale to ensure its high thermal performances and its permeability to water vapour. The fabric finishing system was also designed to provide the possibility of easy tensioning and disassembly for cleaning or replacement. An innovative device, based on plastic zips, was developed and patented within the project. As part of the process, specific studies were developed about cold bridges, thermal capacity and environmental impact of the system. The wallpaper was finally tested and monitored to assess its in-situ thermal performance and the assembly procedure on a building at Politecnico di Milano.