Denim Insulation vs. Fiberglass Insulation: Acoustics and Fire Resistance
Acoustics: Contractors and builders often mention the noise reduction coefficient, or NRC, when discussing the acoustic performance of insulation. NRC values commonly range from 0 (reflects all sound) to 1 (absorbs all sound), but it's possible to have an NRC above 1, depending on the material's shape or surface area. Fiberglass batting with a thickness of 3.5 inches (8.9 centimeters) delivers an NRC of 0.90 to 0.95 [source: NRCratings]. The same thickness of denim scores 1.15, which means blue beats pink again when it comes to blocking airborne sound transmission [source: Bonded Logic].
Fire resistance: In the U.S., the fire resistance of materials is generally rated as Class A, B or C, according to the applicable standards published by both Underwriters Laboratories and ASTM International. Class A denotes the ability of a substance to withstand severe exposure to fire originating from sources outside the building. Both unfaced fiberglass and denim insulation have received Class A fire ratings. It should be noted, however, that the brown paper (or facing) on some fiberglass batting is flammable.
So, denim can hold its own against the usual suspects in terms of meeting the basic functional requirements of insulation. Of course, the economic benefits of using denim insulation aren't immediately apparent. The initial costs of denim far exceed those of fiberglass. According to the Home Depot Web site, UltraTouch denim insulation retails for $6 per roll (16 inches by 48 inches or 41 centimeters by 122 centimeters), while Owens Corning fiberglass insulation costs $3.15 for the same size roll. That works out to about $1.12 per square foot for denim insulation and about 60 cents per square foot for fiberglass.
Denim insulation is easy to install, however, and that can save time and money. We'll tackle installation on the next page.