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From the Editors of E/The Environmental Magazine
Insulating with Least Earth-Impact
Which spray insulation products are safest?
Spray insulation is commonly used to fill spaces in unfinished walls, attics and floors. Most of it is made from polyurethane and closed foam cells, which means it forms a nearly impenetrable barrier. The material is widely recognized as a highly efficient insulator, effectively reducing heat transfer.
Despite the practical benefits, however, there are some environmental and health drawbacks. Although chlorofluorocarbons, known as CFCs, were phased out by the insulation industry because of the damage they were shown to inflict on the Earth’s ozone layer, spray insulation is today typically blown into place with hydrochlorofluorocarbons, CFC-alternatives that are still not completely ozone-friendly. They, too, are set to be phased out completely by 2030). Also, polyurethane can off-gas formaldehyde and other irritants, potentially jeopardizing indoor air quality and causing discomfort to those with chemical sensitivities.
Meanwhile, open-cell insulation such as Icynene requires no ozone-depleting chemicals in its manufacture and is usually blown into place with water. Also, it emits no harmful or irritating chemicals, yet provides a thermal barrier said to be more than 30 times as effective as traditional fiberglass insulation. The downside of open-cell foam is that it is derived from petroleum products and, as such, requires the extraction of finite fossil fuels.
While newer and less well known, Air Krete is a thermally efficient and non-toxic spray insulation that is easily foamed into open or closed cavities in walls, roofs and ceilings. The product’s basic raw-material components are air, water and cement which, when combined, create a cost-effective, safe and high performance product. The National Audubon Society installed Air Krete in its New York City headquarters as part of an overhaul designed to green up that organization’s entire operation.
Beyond sprays, there are many other forms of healthy and environmentally responsible insulation, such as cellulose, cotton, radiant metal barriers and plastic PET batting. Some such products can be found on the shelves of local building supply stores or at Home Depot. But for the widest selection, green-building specialty stores such as the Environmental Home Center in Seattle, which sells online, are a good bet. Others can be found by searching for local retailers, by product desired, at greenerbuilding.org, a service of the non-profit Center for ReSource Conservation, based in Boulder, Colorado.
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