Fiberglass insulation is commonly found in air ducts, pipes, roofs, walls and floors. There are two types: fiberglass loose-fill insulation, which is blown in, and fiberglass blanket insulation, which comes in batts or rolls and in different densities, widths and lengths. Fiberglass is fibrous and made of sand and recycled glass, rendering it naturally noncombustible. If exposed to water, it won't retain moisture; instead, it will dry out and retain its original R-value. R-values for fiberglass insulation range from R-11 to R-38.
Fiberglass insulation can reduce energy use in homes and lower utility bills. This is why the North American Insulation Manufacturers Association considers it a cost-effective and energy-saving product. It has environmental benefits, too. Because it improves buildings' energy efficiency, fiberglass insulation helps reduce the amount of fossil fuel combustion needed to cool and heat buildings. The amount of carbon dioxide emitted into the atmosphere is thereby reduced.