How Green Is Cellulose Insulation?

Posted on July 14, 2008
Tag(s): Energy, Going Green, Green Building
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We all know that a well insulated house is more energy efficient than one that lacks proper insulation. Several types of insulation are available, so which one is the greenest? This week, we’ll take a look at the various types.

Cellulose insulation has high recycled content (approximately 80%) of post consumer newsprint and other wood fiber feedstocks and provides excellent performance of thermal insulation. Its R-value averages 3.4 per inch.

Another environmental attribute: It uses up to 90% less energy to manufacture than mineral wool.

Typically, non-hazardous boric acid is used as a fire retardant and makes up about 20% of cellulose insulation by weight. Dust that is released into the air during installation may be irritating and unpleasant, but the benign ingredients in cellulose insulation (including fire retardants), do not pose a health hazard. Low-dust cellulose is now available for blown in insulation to maintain a clean work environment.

Studies have shown that the dense fiber structure of cellulose and the fire retardants slow the spread of fire through a building, giving occupants more time to escape and fire fighters more time to save the structure. It has also been documented that cellulose insulation has a higher fire resistance than fiberglass insulation.

Wet-spray and loose fill cellulose guard against air infiltration through ceilings and exterior walls better than fiberglass batts. Cellulose insulation fits tightly against pipes, wires and electrical boxes creating a tight thermal barrier. This reduces the amount of energy required to heat and cool a structure.

Wet spray cellulose is used to fill wall cavities and then covered with sheetrock. Even though all loose-fill insulation settles after installation to some extent, the R-value and coverage data are always stated at settled density. This means that until settling occurs, homeowners are getting an even higher R-value out of the product. It also maintains its resistance to heat transfer under virtually all weather conditions in North America.

Source: Cellulose Insulation Manufacturers Association