By Steve Graham, Networx
Buying insulation is a lesson in the complexity of measuring sustainability. Insulation is designed to conserve energy, so all insulation companies can claim to be green — and most do. But materials, production-cycle energy and toxicity are all other factors to consider. Considering all that, how green is traditional fiberglass insulation, and is it getting greener?
Fiberglass batts are in the walls and ceilings of 90 percent of U.S. homes. They are cheap and efficient, providing the greatest energy savings per dollar spent on insulation. Twelve inches of fiberglass batts offer a thermal resistance to R-39, the recommended minimum for ceilings in most of the country, and cost about 60 cents per square foot.
Loose-fill fiberglass insulation is less dense but also effective. Loose-fill cellulose insulation, a popular new alternative, is more dense than either type of fiberglass. However, it is also more expensive and will settle, losing insulation value over time.
Either type of loose-fill insulation can sneak into every gap and crack, where batts might come loose or fit poorly around wiring and light fixtures. Batts are easy to install but hard to install well. Loose batts and flimsy installation will dramatically reduce insulation values.
Most new insulation products, like soy foam insulation, can’t beat fiberglass on value, so they publicize their recycled materials and low-energy manufacturing. Fiberglass is starting to catch up on materials. The industry average is now 30 percent recycled glass fibers — an improvement, to be sure, but far below the 80-percent recycled newspaper content in some brands of cellulose insulation.