Innovation Challenge Spotlight: Insulation

Tags: insulation (1) , innovation challenge (1) , green insulation (1) , green building (2)

The Innovation Challenge: Create a building product that is safe, healthy, affordable, effective, and designed to be returned safely to nature or industry after use. This blog, posted weekly leading up the announcement of the Innovation Challenge winners on November 15, spotlights the key issues with conventional building materials and how the ten finalists’ innovations stand out. This week, we focus on insulation.

Insulation reduces the need to artificially heat and cool. As heating and cooling is energy-intensive, installing the most effective insulation has been touted as a key environmental consideration for builders. Yet an insulation choice is actually very complicated.

Conventional options are often laced with toxic flame retardants. Many flame retardants are reproductive and developmental toxins.1 Both brominated flame retardant HBCD and chlorinated flame retardant TCPP are common in insulation materials. HBCD is generally considered more dangerous than TCPP,2 though both should be avoided.

Both spray foam and foam board require a chemical blowing agent. While the ozone-depleting blowing agents of the past have mostly been phased out, manufacturers sometimes use hydrofluorocarbon (HFC) blowing agents instead. These gases don’t deplete the ozone layer, but they are very strong greenhouse gases.3

A study by Alex Wilson of the Environmental Building Network found that the Global Warming Potential (GWP) of HFCs is so high that it can take over 30 years for a building insulated with these materials to offset (in avoided emissions from heating and cooling) the global warming impact from the blowing agent leaking from the foam and from the embodied energy inherent in producing the insulation. This is very high compared to other materials; all other materials included in the study had an embodied emissions payback period of less than 6 years.4

HFCs aren’t the only blowing agents available. When choosing an insulation material, look for options without HFCs and without halogenated flame retardants.

How the Finalists Stand Out
Two finalists bring insulation materials to the Innovation Challenge. The first, Ecovative Mushroom® Insulation, is made from agricultural wastes bound together with a fungal material. The second, Bellwether Materials’ Softbatts, is made from waste sheep’s wool. Both materials are naturally fire-resistant and do not require added, toxic flame retardants or the blowing agents that contribute to climate change. They are also compostable and can return to nature after use.


1 The Green Science Policy Institute. (2010). Halogenated Flame Retardant Chemicals. Retrieved from

2 Wilson, A. (2013). Getting Flame Retardants Out of Foam Insulation. Environmental Building News, 22(1). Retrieved from

3 Wilson, A. (2010). Avoiding the Global Warming Impact of Insulation. Environmental Building News, 19(6). Retrieved from

4 Wilson, A. (2010). Avoiding the Global Warming Impact of Insulation.