Last Updated: Jul 10, 2021
Properly insulating a home is one of the most critical elements of an energy-efficient, sustainable home. Along with super tight building envelopes, high-efficiency insulation is one of the foundational principles of passive house design. As the building industry has evolved, however, new types of insulation are continually hitting the market. Foam insulation, for example, is one popular option that is easy to apply (especially for container homes) and high performance. However, not all homeowners will choose to use insulation containing byproducts of the petrochemical industry in their homes. Cotton batt insulation offers a natural insulation alternative with a low environmental footprint alongside optimum performance and health targets.
When most of us think about greenhouse gas emissions, we probably think about huge industries or gas-guzzling SUVs. However, every product that we purchase and use also comes with a carbon footprint. In the case of our wardrobes, "fast fashion" is also responsible for an enormous amount of carbon emissions. The World Bank estimates that 10% of annual global carbon emissions stem from the fashion industry - which amounts to more than all international flights and maritime shipping combined. If the sector continues to grow at the current rate, its emissions will increase by more than 50% by 2030.
What does our wardrobe have to do with how we insulate the walls, foundations, and roofs of our home? Americans, on average, throw away about 80 pounds of clothing items every year. Reducing the clothing we purchase is undoubtedly one aspect of a more sustainable lifestyle. However, finding ways to recycle and reuse old garments is also essential. Donating to Goodwill or other local charities is an excellent first step. Turning your old jeans and other cotton garments into high-performance insulation for your home is another way to reduce landfill waste.
Cotton batt insulation is made of small, cellulose fibers sourced from used denim jeans and other types of clothing items. It was initially developed in the 1990s from the enormous amount of scrap denim sourced from clothing manufacturers. Today, cotton batt insulation is usually made from recycled jeans and other clothing items. The individual fibers are bound together in batts, which are easy to install in walls, floors, attics, and ceilings. Cotton batt insulation products are usually sized to fit between the studs of your home and come in different widths for a variety of R-values.
The most obvious environmental benefit of cotton batt insulation is that it allows homeowners to reuse and recycle materials that would otherwise end up discarded in landfills. Waste from the fashion and clothing industries is continually rising.
A publication from the World Economic Forum states that the fashion industry has doubled production in the past 15 years. Meanwhile, the lifespan of clothing has decreased by about 40%. Unfortunately, 73% of this discarded clothing ends up in landfills. Only about 12 percent of all clothing items get recycled, most of which are destined for mattress fill or insulation.
Increasing homeowner demand for recycled cotton batt insulation could stimulate demand for more clothing waste to be given a second life as insulation products. Unlike foam-based insulation alternatives, cotton batts can be made from 100% natural materials. This inherent quality reduces the possibility of volatile organic compounds (VOCs) from negatively affecting your indoor air quality.
Cotton insulation products can play an important part in helping our society transition into a more circular economy. Traditional economic patterns are linear in that they follow the following process: extraction, production, use, and then discard as waste. A circular economy is founded on the principles of reducing waste and pollution through the design process, keeping products and materials in use, and regenerating natural systems. Cotton batt insulation would reduce waste by giving old clothing "new life" as home insulation. When insulation does need to be replaced, cotton batt insulation is entirely biodegradable, thus reducing demand for further landfill space.
Cotton and fiberglass insulation can be hard to differentiate at first sight. Both of them come as batts that are relatively easy to install. In terms of insulation performance, fiberglass batts do slightly outperform their cotton counterparts.
In general, cotton insulation will have an R-Value that ranges from 3-4 per inch. In contrast, fiberglass insulation batts will have an R-Value of 5-7 per inch. In colder climates that require more insulation, thicker batts or doubling the layers of cotton insulation can compensate for the slightly lower R-Values. It should also be noted that should cotton insulation be compressed, the R-value and performance of your insulation will be drastically lower.
Fiberglass insulation does come with certain disadvantages that are often ignored. Installation of this common insulation material often leads to skin and eye irritation during the installation process. Inhaling the small fiberglass shreds can cause lung damage and respiratory problems. On a more severe level, a 1994 study by the U.S. Department of Health and Human Services determined that fiberglass was "reasonably anticipated to be a carcinogen." Subsequent studies have found that fiberglass insulation within the home studs generally provides limited risk to homeowners. However, opting for more natural cotton batt insulation can further reduce your vulnerability to potentially dangerous health issues.
Cotton batt insulation offers excellent acoustic properties for homeowners living in areas where noise could be a problem. Whether you have noisy neighbors, high winds, or live next to the train tracks, thick layers of cotton batt insulation can provide silent interiors.
Cotton insulation has virtually zero fire resistance. Wool insulation is a similar natural insulation alternative. The lanolin that is naturally present in wool, however, does offer fire resistance properties. For homeowners who opt to install cotton batt insulation, using borate flame retardant products can drastically reduce your home's vulnerability. Boric acid, borax pentahydrate, and borax decahydrate are three natural flame retardants. They offer protection for cellulose insulation while also protecting against insect infiltration.
No, cotton batt insulation is susceptible to water damage. Roof or plumbing leaks, especially when not quickly detected, can destroy your cotton insulation and lead to expensive renovations. Of course, the same is also true of fiberglass insulation, and over half of all new homes continue to opt for this insulation option.
Water leak detectors can help to avoid damage to your insulation and other parts of your home. However, even if homeowners spot a leak relatively quickly, the fibers in cotton insulation can become compressed with even minimal moisture exposure. This problem can lead to the development of mold. If water damage is a threat, homeowners might consider opting against cotton insulation products.
Cotton batt insulation costs $1.20 to $1.50 per sq. ft. for an R-value of 19, which is roughly 6 inches thick. This price is for material only and does not include the cost of installation by an insulation professional.
Finding and using cotton batt insulation and other recycled and reclaimed home building materials is a great way to reduce the embodied energy footprint of your household, limit the demand for further extraction of raw materials, and reduce waste. Cotton batt insulation is also a healthier alternative for homeowners who want to take practical steps to improve air quality and reduce chemicals in their homes.
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.