Multilayer Recycled Textiles: Sustainable Retrofitting and Thermal Insulation Impact

The construction sector plays a significant role in global energy consumption and carbon emissions; improving the energy efficiency of existing buildings a fundamental requirement for sustainable development. Retrofitting the internal walls of buildings requires insulating materials that not only provide effective thermal performance but are also environmentally friendly, low-carbon, and compatible with circular-economy principles. In this context, recycled textile materials, especially cotton and polyester, are gaining increasing attention as sustainable insulation systems. This review article aims to critically evaluate the thermal insulation, environmental performance, and potential use of woven textile insulation structures based on recycled cotton, recycled polyester, and an equal combination of both in internal wall retrofitting. This article systematically reviews the available scientific literature and presents a conceptual framework based on multilayer woven structures. This review highlights that increasing the number of layers can play a significant role in improving thermal resistance, reducing heat transfer, and limiting internal energy loss by increasing the static air spaces between the fibers. Furthermore, the use of recycled textiles can also achieve environmental benefits such as reducing textile waste, conserving natural resources, and reducing overall carbon emissions. The research also offers a useful guiding framework for the development of sustainable building technologies based on low-carbon construction, efficient use of resources, and a circular economy.