Properly insulating a structure using Johns Manville building insulation helps preserve our environment by reducing energy consumption for heating and cooling, reducing the pollution resulting from fuel burning, reducing the emission of hazardous air pollutants during manufacturing and reducing waste through the utilization of recycled materials. High performance insulation for extra thermal control. It is lightweight, thermal and acoustical fibreglass insulation and best for use in 2 x 4 walls, crawlspaces and underfloors. 50% recycled content JM fibreglass insulation carries the UL Ecologo certification for reduced environmental impact