Fiberglass insulation, manufactured in the United States since 1897, is made from silica, sand and limestone with binders, fire retardants, glass, and sometimes dyes.
  It is generally manufactured by melting the sand and recycled glass into glass fibers. These fibers are then held together with a binder.
To comply with the Environmental Protection Agency’s (EPA) guidelines, 20% recycled glass is required. Most manufacturers currently exceed this by 10% or so. However, 90% recycled glass content is feasible.
In addition to its recycled content, fiberglass has other advantages. It is inherently non-combustible and not subject to pests, making it the least chemically treated insulation. Mineral oil and silicone are commonly added to control dust. Most fiberglass batt has good thermal efficiency, rated R15 to R28 and costs approximately 20¢ per foot. Contractors are familiar with this material, giving it an extra advantage.
Demystifying concerns about sustainability and health effects of conventional fiberglass is challenging. The concerns have included tiny short glass fibers being an irritant to skin and respiratory system, especially among production workers and installers. Traditionally used phenol formaldehyde binders and dyes used in the pink variety are considered toxic and unsustainable. In addition, it is possible that batt insulations can be an absorbent for VOCs, although use of an impermeable membrane, called a vapor barrier, can cover the insulation and assist in resolving this problem.
Because of these toxins and free particulates, manufacturers have been required to post cancer warning labels and offer recommendations for safer installation practices which include: wear a respirator; avoid contact with skin by wearing long sleeved clothing and gloves; wear eye protection; wash your hands immediately after handling; shower and wash your work clothes separately from other clothes as soon as possible and wipe out the washer when finished.
Once properly installed and carefully separated from a living space, fiberglass should pose little health risks to occupants. It is recommended that fiberglass without a fully protective enclosure be kept away from HVAC units to prevent the tiny fiber particulates from being recycled by the vents into the living spaces.
Some manufacturers are addressing these health concerns and developing more sustainable fiberglass products. Among them are fiberglass batts wrapped in perforated polyethylene and a new type of fiberglass which does not require a binder. Because there are no binders or other chemicals, pollution emissions during manufacturing are negligible and offgassing should prove to be of no concern. Other new developments include use of an acrylic resin replacing a formaldehyde-based resin binder.
Many years ago an enterprising company developed a machine specifically to enable the recycling of insulation. They named it “The Big Green Machine Insulation Reprocessor.” This machine was developed with the contractor in mind so that used or left-over insulation could be chopped up and reused. Now resurrected and redesigned, the GREEN MACHINE can quickly grind scrap to a predetermined fiber length.
Fiberglass Loose Fill is essentially the same product as batt. Loose fill needs even more careful measures taken during installation to prevent breathing of these fibers. Full separation from the living spaces is imperative so that loose fibers are behind tightly constructed boards, even in the smallest spaces. Loose fill insulations have a tendency to shift downward over time, diminishing some of their effectiveness.
Fiberglass Board is also available with the same advantages and disadvantages of all fiberglass insulation. However, most of the board versions contain more resin binder to make them denser and more rigid.


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