The energy efficiency benefits of insulation are easily achieved and widely understood. While preservationists generally do not recommend its installation between walls of historic buildings – due to its potentially damaging effects to historic materials, high cost, and less effective energy savings – insulation installed in the attic and roof can save a historic-home owner a lot of money and energy.
While the energy efficiency benefits of insulation are easily achieved, not all types of insulation are equally healthy choices – for the building’s inhabitants or the buildings themselves.
Some cellulose insulation, for example, uses ammonium or aluminum sulfate as fire retardants, as opposed to the less harmful boric acid. Ammonium or aluminum sulfate create sulfuric acid when they react with moisture in the air, causing damage to brick, wood, stone, and most metals. In addition, cellulose insulation can cause breathing difficulty and irritation among building inhabitants due to dust and released chemicals, such as formaldehyde, chlorine, fluorine, lead, iron compounds, sulfur compounds, cadmium, nitric oxide, and methane, among others.
Another commonly used insulation material is fiberglass, which is made of tiny glass strands. Though somewhat safer for building materials than cellulose insulation, fiberglass insulation can cause itchiness and irritation of the skin, eyes, nose, and throat when it comes into direct contact.
How can historic-building owners choose the least harmful products while further practicing environmental sustainability with their insulation solutions? Luckily, many new insulation products exist that achieve energy efficiency with natural and recycled materials, such as cotton, hemp, and paper.
Bonded Logic, Inc., a member of the U.S. Green Building Council, offers Ultra Touch, a non-irritant, cotton insulation made from 85% post-industrial recycled materials. The cotton insulation is made from recycled denim scraps, 100% recyclable, and it is free of VOCs and formaldehyde.
Dutch company HempFlax manufactures hemp insulation with some polyester filler and soda, which acts as a flame retardant. Hemp is naturally resistant to various types of insect infestation, thus avoiding the need for chemical repellent.
Excel Warmcel thermal insulation is made from 100% recycled newsprint and is fully recyclable after use. Free from VOCs and formaldehyde, this type of insulation will not emit toxins, and it is fire resistant as well.
Historic-home owners are used to creative thinking and thoughtful application when achieving environmentally sustainable preservation. Proper installation of insulation offers a useful method of energy savings and efficiency. As the negative health effects of some insulation types become more apparent, environmentalists and manufacturers are developing newer, safer, and more environmentally sustainable insulation choices – allowing the historic-home inhabitant various choices in the realization of their home’s green potential.
For More Information:
Bower, John. “Cellulose Insulation,” Healthy House Institute.
Ibid. “Fiberglass Insulation: Use with Care,” Healthy House Institute.
Dunn, Collin. “Tree Hugger Picks: Green Insulation,” TreeHugger.com
“Healthy Foundations,” National Geographic Green Guide.
Lord, Noelle. “Embracing Energy Efficiency,” Old House Journal.com.
Rose, William B. “Should the Walls of Historic Buildings Be Insulated?”, APT Bulletin, Vol. XXXVI, No.4, 2005.
Smith, Baird W. Preservation Brief 3: Conserving Energy in Historic Buildings. National Park Service.