Fiberglass Insulation

Modern fiberglass was invented by accident in 1932, when a lab worker discovered that a high-pressure blast of air could turn a stream of molten glass into fine strands of glass. Owens Corning trademarked Fiberglas© in 1938 and began to find new uses for the material. In addition to being made into insulation, fiberglass has been woven into fabric and used to make fishing rods, boat hulls, rigid panels
and other products.

Recycled content, but energy-intensive manufacturing

Like all insulation, fiberglass insulation can be considered a "green" material because it helps conserve energy, thus lessening emissions from fossil fuels that are burned to generate electricity or heat. Most fiberglass insulation also contains a certain percentage of recycled glass, another green value. However, the manufacturing process for fiberglass is very energy intensive. High furnace temperatures (up to 2500 degrees F) are required to turn molten glass into fiber, and this factor makes fiberglass insulation less desirable than its main competitor in the insulation market, cellulose insulation.

Batts, blankets and blown-in insulation

Fiberglass insulation is available in several forms. Glass fibers are formed into narrow blankets called "batts" that come in different thicknesses and widths. The widths correspond to standard spacing (primarily 16-in. and 24-in. on-center spacing) between studs, joists and rafters. Batts are available unfaced or faced with different materials such as kraft paper, plastic or foil. Facings usually provide several benefits: simplified installation, an air/vapor barrier and (with foil facings) a radiant barrier.

Fiberglass insulation also is available in blanket form (wider and thinner than batts, with plastic facing on one or both sides), and as a loose-fill insulation designed for blown-in installation. Blown-in fiberglass insulation is primarily used to insulate unfinished attic spaces.

PROS & CONS
Weighing the benefits and limitations of fiberglass insulation will help you decide whether this is the right insulation option for your house.

PROS

• One of the least-expensive types of insulation available.
• Widespread availability.
• Easy installation (although careful installation is required to maximize energy savings)

CONS

• Energy intensive to manufacture (not nearly as "green" as cellulose insulation).
• Low R-value compared to other types of insulation (around R-3.2 per in.)
• Highly permeable; will not stop energy losses due to air leaks.
• Irritating and potentially hazardous to handle (dust masks and protective clothing required during installation & handling).
• Favored as living space by mice & other rodents.
• Will lose R-value when wet or compressed.
• Can absorb moisture and support mold growth.

Let Dr. Energy Saver's home energy specialists help you decide whether fiberglass is a good choice for your home insulation needs. Call or contact us online for a Free Home Insulation Estimate.

Back to previous page