When it comes to green building products, insulation stands out as a natural fit. After all, one of the main tenets of green building is increasing energy efficiency, and long before being green was in vogue, that’s always been insulation’s primary purpose. Now, with the rush toward all things green in the home building industry, insulation is one of the first categories builders look to when setting out to construct an environmentally friendly home.
“You could say all insulation is green, regardless of what it’s made of,” says Robin Bectel, director of communications for the North American Insulation Manufacturers Association, a trade association of fiberglass and mineral wool insulation manufacturers based in Alexandria, Va. “By definition, insulation saves energy.”
Yet, as with all areas of green building products, insulation comes in different shades of green, based on its recycled content, whether it gives off any emissions, and the amount of energy it saves versus the amount of energy needed to produce it.
Fiberglass and cellulose manufacturers, who enjoy the overwhelming majority of residential sales in the United States—an estimated 80 percent to 90 percent—go tit-for-tat to differentiate themselves on those criteria. Fiberglass advocates, for instance, tout the fact that their product saves 12 times the amount of energy it takes to produce in its first year of use.
But cellulose manufacturers, who make insulation out of ground-up recycled newspapers, say their product far outshines fiberglass. “Cellulose saves over 200 times the amount of energy it takes to make it,” says Dan Lea, executive director of the Cellulose Insulation Manufacturers Association in Dayton, Ohio. Cellulose producers also like to point out that their product is made of up to 80 percent recycled content, compared with the 35 percent of recycled glass that goes into fiberglass insulation.
Of course, in terms of performance and ease of installation, each category has its dedicated followers. “We started using cellulose in 1992, when the spotted owl had a corner on the wood market, and a lot of people were using steel framing in their homes,” says Craig Matteson, director of sales and technical services at ARC Insulation in Romeoville, Ill., which insulates approximately 800 homes a year. “We just found that in terms of performance, cellulose won hands-down when compared to conventional fiberglass insulation.”
Fiberglass installers, of course, feel quite differently, especially those who apply blow-in fiberglass, using the same kind of wet spray machine cellulose installers employ. “Unlike cellulose, spray-on fiberglass doesn’t absorb the water you use to install it,” says Jesse Horn of Horn Insulation in Rantoul, Ill., which insulates more than 500 homes per year. “Because fiberglass is lighter and less absorbent, once you spray it in there, the water tends to just drain right out.” Horn’s point is important, as any insulation can promote mold growth inside a wall if it holds moisture for prolonged periods.
While industry estimates peg other types of insulation as making up just 10 percent or less of the overall market, other “green” choices abound. For instance, The Green Building Products Directory, published by Brattleboro, Vt.-based green watchdog group BuildingGreen, lists a full spectrum of insulation types from mineral wool; rigid polyiso panels; EPS foam; and foamed-in-place, cotton, and even soybean-based products as green. Atlanta-based Greenguard Environmental Institute, which advocates for a healthy indoor environment and measures the emissions of thousands of building products, has given its stamp of approval to insulation types ranging from fiberglass to mineral wool, expanded polystyrene (EPS) and polyester.
Growing Concern A concern over indoor air quality, and the hyper-focus on using low-or no-VOC-emitting building products, has spotlighted that area as a central facet of the green debate. Fiberglass manufacturers have grappled with the use of formaldehyde as a curing agent in their product (see “Formaldehyde Factor” at right), while cellulose producers are often questioned on whether their product introduces tiny fiber particles into the indoor air environment.
The debate has helped a relative newcomer, the cotton insulation market, enjoy increased interest—and sales—in the past two years. Manufactured from the leftover scraps of denim jeans and cotton shirts produced by the textile industry, cotton insulation provides high R-values, while borate additives help produce a Class A fire rating. The product also is particularly effective as a sound barrier in homes.
“Due to the irregular shape of the natural fibers, cotton has very good sound absorbtion,” says Randy Robinson, regional sales manager for Inno-Therm Fiber Insulation. “A lot of people use it in quiet rooms or media rooms, where they’ve got big speakers and sound they want to control.”
Sherry Furr, a cotton insulation distributor and installer who works at InsulTechonologies, says one of cotton’s primary benefits is its ease of installation. It comes in rolls, and can be cut with scissors, so pre-sized batts aren’t an issue. “You don’t need any special equipment or masks or gloves,” Furr says. “And it doesn’t have the particles that get into your skin, like fiberglass, because it’s just cotton.” To stress this point, Inno-Therm uses a picture of a soft-skinned baby, perched on top of its insulation, on its Web site, and the phrase, “Go Ahead, Touch It.” It should be noted, though, that some health experts question whether airborne cotton fibers can create health risks, as well.
And of course cotton, like cellulose, is heavier than fiberglass. That means flat, attic applications reach a threshold that restricts more material from being used, due to loading limits. Cotton also tends to be about a third more expensive than fiberglass, which puts it in the same price range as cellulose. Robinson points out, though, that cotton insulation doesn’t have a government warning about cancer on its label, as fiberglass does. “So cost isn’t everything,” she says.
This story first appeared in BUILDING PRODUCTS magazine.
