This article looks at the history of the use of insulating materials in architecture, starting with primitive huts where furs were used to regulate the internal environment. Evolution has led to a variety of traditional and modern insulation materials including wool, linen and cellulose. Sustainability and environmental considerations in material selection are emphasised. Innovations such as aerogels and vacuum insulation panels, which provide high thermal efficiency, are reviewed. The use of transparent insulating materials that interact with light to provide insulation and natural light is also described. Digital technologies for measuring insulation levels and modelling comfortable interior spaces are presented. New approaches to interior insulation, including organic compounds and innovative materials, present popular solutions for protecting buildings and occupants from external influences.