Insulation Properties of Denim, Wool & Cotton

Updated April 17, 2017

Alternatives exist to the itchy, scratchy fibreglass insulation that still maintain an R value in the median range of R-13. Denim, wool and cotton insulation all produce similar R values. R-value indicates insulation's resistance to heat flow, and the higher the R-value, the greater the efficacy of the insulation. Slightly higher in cost, these natural fibres can be installed without using protective clothing and respirators. If you're looking for a green alternative for insulating your home, denim, cotton and wool are worth consideration.

Denim Insulation

Denim is not just for blue jeans anymore. Denim insulation, made from 85 per cent natural denim and cotton fibre factory scraps, is an effective green insulation. It has an R-13 rating in 2 by 4 walls, or R-3.4 per square inch. Treated with a Boron-based fire retardant that is also resistant to pests and the growth of mould and fungi, denim absorbs sound and works well in blustery weather.

Wool Insulation

Wool, long used as a way to keep the human body warm, is now found in the walls of homes. As insulation, it provides an R value of R-3.5 per inch. Treated with either Boron or Thorlan IW to reduce pests, mould and resist fire, wool holds large amounts of water, which can be an advantage in some areas.

Cotton Insulation

Cotton has transitioned from cotton balls to cotton insulation. Versatile in its uses, this material can keep you warm even when you're not wearing it. Made from recycled product like its denim cousin, cotton has found yet another use as home insulation. Eighty-five per cent cotton fibres, the remaining 15 per cent are plastic fibres that are treated with borate to deter fire, insects and rodents. It has an R value of R-3.4 per inch. Non-toxic, it is safe to install without protective wear.

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About the Author

Joni Ryan has been writing public interest and how-to articles since 1989. Based in a suburb of Charlotte, N.C., Ryan has written for the "Charlotte Racing News," "The Current" and "The Oceana Herald." She studied the principles of business ontology for two years with the Unicist Research Institute. Ryan completed the Coach Training Alliance life coaching program in 2006.