Green Insulation 101: Cellulose, Fiberglass, Foam and Cotton

Choose natural forms of insulation for your home.

UltraTouch Natural Cotton Fiber Insulation

UltraTouch Natural Cotton Fiber Insulation is made from recycled denim.

Photo Courtesy Bonded Logic

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Wall and ceiling insulation reduces noise and helps keep your home warm in winter, cool in summer. Whether you’re building a new home or improving an uninsulated one, choose natural forms of insulation. Here’s a look at several of the more eco-friendly types.


• Recycled newsprint that’s blown into walls, ceilings, and attics. A water-activated adhesive helps it stabilize when applied to an open cavity. Can also be densely packed into closed cavities.
• Treated with nontoxic borate or ammonium sulfate fire retardant.

Soy-Based Polyurethane Foam 

• Sprays on, then expands to fill structural cavities.
• Seals leaks by filling tiny crevices and cavities.
• Made from soybean oil (a renewable resource) and petrochemicals.
• Does not use ozone-depleting CFC- or HCFC-based blowing agents. Uses water- or carbon dioxide-based blowing agents.
• Requires special equipment and a contractor.


• Comes in batts or blown-in formulation.
• Most contain at least 30 percent recycled-glass content.
• Many brands contain a phenolformaldehyde binder; some formaldehyde-free products are available.
• There’s debate over whether inhaling airborne fibers causes cancer.


• Created from clothing manufacturing remnants (denim, T-shirts). Comes in batts like fiberglass.
• Treated with a natural, boron-based fire retardant/pest inhibitor.
• Doesn’t itch; easy to handle.
• Contains no formaldehyde.
• Difficult to cut; takes longer to install.

Source: Rich MacMath, architect, Austin Energy Green Building Program; Green Building Products (Building Green, 2005).