Abstract: An insulation product includes a fibrous layer and a facing layer. The fibrous layer includes synthetic fibers, has first and second opposing major surfaces, and has an average denier of less than about 3.0. The facing layer includes a paper-backed facing adhered to one of the first and second major surfaces of the fibrous layer. The insulation product has: a flame spread index of no greater than 25 and a smoke developed index of no greater than 50 as measured in accordance with ASTM E84; a thickness of between about 0.5 and 2 inches; and a thermal conductivity of less than about 0.3 Btu-in./ft2-hr-° F.