Johns Manville Formaldehyde-free Climate Pro blow-in loose-fill fiber glass insulation is a premium alternative to cellulose. It is blown into attics, nonconforming spaces and hard-to-reach areas, like corners, edges and around framing. When applied to the recommended thickness and specifications, one can be assured that the home is energy efficient, with minimal heat loss. And unlike cellulose, it won't settle, decay or provide food for animals or microbes.