Textile waste is one of the most challenging forms of waste to treat since it is often a blend of materials, and it can take years to centuries for it to degrade naturally. It is, therefore, essential to look at sustainable options for producing clothing and recycling it. From a post-consumer perspective, a significant focus is placed on recycling the waste generated. However, this could be made more efficient by selecting appropriate materials and production methods to enhance the final garments’ recyclability and minimize waste generated by their production. Textile structures are porous, and in many cases, this can also be attributed to the fibers used to produce them. This has led to thermal insulation products being one of the most common items to be created from textile waste since it offers an easy method to create a valuable product with minimal treatment of the waste necessary. The prediction of thermal insulation of textile structures is critically dependent on quantitative characteristics of their morphology and textile fibers’ physical parameters, such as density and thermal conductivity.