The type axis of Residential Insulation segmentation differentiates five material families: fiberglass, cellulose, spray foam, mineral wool, and rigid foam. Fiberglass, the most established option, retains a 35 % market share due to its cost‑effectiveness and broad availability, especially in wall cavity applications. Cellulose, derived from recycled paper, captures roughly 20 % of the market, favored for its superior air‑sealing properties and lower embodied carbon. Spray foam, encompassing open‑ and closed‑cell variants, commands about 25 % of revenue, driven by its high R‑value per inch and ability to eliminate thermal bridges in complex geometries. Mineral wool, valued for fire resistance and acoustic performance, holds an estimated 10 % share, primarily in industrial‑grade residential projects. Rigid foam boards, including polyisocyanurate and expanded polystyrene, represent the remaining 10 % and are preferred for exterior sheathing and basement perimeter insulation. Each material’s contribution to total market size reflects a balance of performance attributes, installation complexity, and regional cost sensitivities, underscoring the nuanced market taxonomy.