Denim vs Cellulose Insulation | Everything you need to know

March 24, 2021

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Denim and cellulose insulation are the most popular recycled insulation products. In this article, we’re going to look at how they are made, their main differences as well as their pros and cons.

Denim / Cotton Insulation

Denim insulation is primarily derived from recycled cotton, typically sourced from discarded jeans. The cotton is collected, cleaned, stretched, and spun into fibers, then mixed with blue indigo dye and a reducing agent called sodium hydrosulphite, which turns the fibers blue in the presence of air. The jeans are transformed into small pieces, free from zippers, buttons, and rivets, then shredded and bundled into 1000-pound bales.These fibers are mixed with other cotton fibers and a non-toxic borate solution, serving as a fire retardant and mold and mildew repellent. The mixture bonds in an oven before being pressed and cut into shape.

Denim insulation finds applications in various products, such as UltraTouch Denim Insulation available in batts and loose-fill for walls, ceilings, floors, and crawl spaces. UltraTouch Radiant Barrier serves automotive, aircraft, and marine uses, protecting against air currents, vapor, moisture, and radiant heat.

Cellulose Insulation

Cellulose insulation, on the other hand, is primarily made from recycled paper and cardboard boxes. Wood chip waste from logging and sawmill operations is broken down in pulp digesters, transforming it into a pudding of cellulose fibers. The fibers are then cleaned and screened multiple times. A thin layer of liquid paper pulp is deposited on a wire screen, and as the water is removed, the cellulose fibers bond together, forming paper. The aper is then pressed and dried through a series of heated rollers. The remaining paper is shredded and treated with boric acid or ammonium sulfate to prevent decay and repel pests, mold, and mildew.

Cost

Denim insulation by Bonded Logic is the sole manufacturer in the US. The cost varies, but for example, a 6-pack of R6.7 16″x48″ batts was previously priced at $36.72. Currently, R19 and R13 batts are available for bulk purchase. Greenfiber cellulose insulation is competitively priced, with a 19-pound bag costing $9.68. Both denim and cellulose insulation achieve an R-value of R3.5 per inch, costing approximately $1.12 and $1.20 per square foot, respectively.

Installation

Denim insulation is easy to handle and doesn’t cause itching or irritation. While it can be cut with scissors, Bonded Logic recommends using specialized tools like insul-knives, foam rubber cutters, grinders, or table saws. Perforated seams have been introduced to address some customer feedback regarding the width of the batts. Denim insulation installs similarly to fiberglass, fitting well around pipes, wires, and outlets.

Cellulose insulation has two installation methods: dry or damp fiber. Dry fiber is common for retrofits in open attics and enclosed walls, while damp cellulose is used for open wall cavities in new construction. Both methods require caution, with damp cellulose necessitating protection of windows, doors, and electrical boxes.

Noise Control, Water Test, and Fire Test

Both denim and cellulose insulation offer good acoustical properties, with denim having a Noise Reduction Control rating of 1.15 and a Sound Transmission Control rating of 52, while cellulose boasts an NRC rating of 0.9 and an STC rating of 44.

In a water repellency test, denim insulation performed poorly, allowing water to pass through easily, while cellulose insulation effectively contained moisture. During the fire test, both insulations showed impressive fire resistance and received a Class A fire rating, thanks to the high percentage of borate in their composition.

Environmental Impact

Denim insulation, with 85% recycled content, diverts approximately 300 tons of material from landfills monthly and is considered zero waste since any scraps can be recycled. It contains no VOCs and is 100% recyclable. Bonded Logic also donates insulation to Habitat for Humanity, a commendable act.

Cellulose insulation, with 85% recycled content, diverts paper and cardboard from landfills and is biodegradable after its useful lifespan of 20 to 30 years. While it cannot be recycled into new insulation products due to fire retardant chemicals, it can be used as mulch and compost.

Conclusion

Denim and cellulose insulation offer eco-friendly solutions, recycling discarded materials and reducing waste. They perform well but are costlier than traditional fiberglass insulation. Denim insulation’s acoustical properties make it an attractive option, while cellulose is popular for attic retrofits. Nonetheless, manufacturers need to bring down prices to make them more competitive. Both insulation types contribute to sustainable practices, but addressing the entire lifecycle of cotton production and fast fashion consumption is essential for a more comprehensive solution.