By: Arthur B. Weissman, Ph.D.
President & CEO, Green Seal

At first thought it would seem self-evident that using thermal insulation products in a building, whether for new construction, renovation, or retrofit, would be a sustainable choice.  After all, the products conserve energy in heating and cooling a building.  What complicates this are the various environmental and health impacts of the insulation products themselves, both in their manufacturing and installation. Therefore, when choosing more sustainable insulation products, we seek to reduce those impacts while retaining the energy-conserving benefits and applicability of the products.

Green Seal faced this challenge when it developed its environmental leadership standard for insulation products (GS-54) in 2015-16.  There are hazards of some sort or another attached to virtually all insulation products on the market today, ranging from the toxic or greenhouse-gas-producing ingredients of foam insulation to the lower performance and propensity to mold of seemingly innocuous cellulose products.  In between are products like wool fibers or fiberglass that have moderate impacts but may not be cost-effective or easily widely applicable.

In its leadership standards, Green Seal seeks to identify the most sustainable products.  We consider this level to be approximately the top 15-20% of products in a category.  It is sometimes hard know which are the top products, due to the multitude of product types and applications.  For example, what works for a fill-in may not work well for a wall, roof, or basement below ground.  As a result, we chose to identify the most sustainable products in each insulation product sub-category (e.g., mineral wools, foam, etc.) that also satisfied the functional needs and requirements.  (All Green Seal standards contain functional performance criteria to ensure that a “green” product actually works well.)

The draft insulation standard we proposed for public comment did not categorically exclude foam insulation products, including spray polyurethane foam (SPF) (whose required agent, MDI, is a proven asthmagen but has no known substitutes) and polystyrene foam (whose blowing agents are potent greenhouse gases). Not surprisingly, the proposal received substantial criticism from some health and environmental groups.  These stakeholders believed that a standard for “green” products should only allow less toxic or harmful products like fiberglass, mineral and animal wools, cellulose, and fabrics like denim.

Green Seal takes all substantive comments on its proposed standards seriously, and we worked with stakeholders to try to resolve differences.  While the final standard did not ultimately prohibit foam insulation, it did incorporate a number of additional protections related to the installation of SPF and the allowable greenhouse gas levels of polystyrene blowing agents.  In our view, SPF and other foam insulation products will continue to be used for applications where they are best suited, and it is better for users to choose the most sustainable versions of these products.

For more information on Green Seal’s GS-54 insulation standard and its standard development process, check out the enclosed website links or email our team at

This is a guest blog written by Dr. Arthur Weissman, President & CEO of Green Seal, the nation’s premier non-profit environmental certification and standard development organization. The ideas and opinions put forward in this blog do not represent those of the Building Energy Exchange or its employees.   


  • Passive House / High Performance

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