Reducing Building Insulation Products’ Embodied Carbon and Carbon Payback Time

(XPS) Rigid Foam Insulation installed on a commercial roof

Globally, society is not yet on a path to avoid the worst impacts of climate change and time is running out. The building and construction industry accounts for nearly 40 percent of the world’s carbon emissions, and the manufacturing of building materials accounts for 11 percent of global carbon emissions. As part of the global solution to address climate change, the building industry must achieve carbon neutrality and deliver solutions focused on climate resiliency.

There has been significant progress in recent years toward reducing its environmental impact.

While there are many contributing factors to this progress, one is the overall efficiency and operational carbon mitigation of the building envelope as we consider thermal, moisture and air performance. The use of insulation, sealants and weather barriers is increasingly important to the performance of a building.

The construction industry has received much attention through the increasing focus on its carbon footprint, also known as embodied carbon. Concrete, steel, and finishes contribute approximately 75 percent of the building’s total embodied carbon (as depicted in the nearby pie chart). Embodied carbon impacts climate change in the near-term, therefore addressing this aspect of building materials is relevant and important.

Another factor to consider is the environmental impacts of the products in application. Higher performing buildings benefit from the installation of quality insulation and air sealing products to directly reduce operational energy usage through a reduction in heating and cooling needs. Not only does this help ensure more affordable housing for occupants, it offers a more comfortable and healthier living environment.

Although insulation products contribute a small portion of a building’s total embodied carbon (identified as “Thermal and Moisture Protection” in the pie chart) relative to other building materials, DuPont Performance Building Solutions (PBS) has set out to drive a more sustainable future, which includes acting on climate change. Extending decades of building science expertise to address sustainability challenges, DuPont PBS has recently announced its 2030 Sustainability Goals, including a 75 percent reduction in greenhouse gas emissions from operations relative to 2019 levels. With the large volume presence in the insulation market, a meaningful and immediate impact will be made by projects that drive progress against this goal, such as launching reformulated Styrofoam™ Brand XPS Insulation and Froth-Pak™ Foam Insulation that utilize a reduced Global Warming Potential (GWP) blowing agent . The result is a reduced embodied carbon profile for these products, which are being launched in 2021.

Long-term Impact on the Carbon Footprint

There are many contributing elements that go into a product’s carbon footprint, including:

  • raw materials;
  • manufacturing processes;
  • transportation;
  • installation;
  • maintenance, and
  • end of life/recycling.

In the case of blowing agents used in some insulation products, their full impact on the environment takes place over decades since they are contained within the product, diffusing very slowly out of the product in-use and at the end of life.1 Environmental Product Declarations (EPDs) help customers understand the impact of blowing-agent GWP on the final product’s embodied carbon and total carbon footprint over the entire life cycle.

Insulation products play a critical role in a building’s operational carbon footprint. This can be quantified through well-known mathematical modeling.2 However, this information is not required or standardized for insulation EPDs. Simply put, in the first five years of a building’s life, when utilizing natural gas for heating, the avoided carbon emissions of one inch of insulation can reach two times that of its total embodied carbon. This is often expressed as carbon payback time.

The carbon payback time of insulation products is relatively short and getting shorter, even for those using blowing agents with higher characteristic GWP (such as HFCs). For example, two inches of blue StyrofoamTM Brand XPS Insulation has a typical payback time of 4.5 years in colder climate zones, but the reduced GWP StyrofoamTM Brand XPS Insulation has a payback time of only 2.5 years based on the positive in-use benefits delivered.3 This carbon payback time estimation only considers the carbon savings due to reduced energy usage related to heating and is even shorter when one considers the additional energy savings from reduced requirements related to cooling. Over the anticipated 75-year lifetime of a building, the carbon emissions saved through energy use reduction associated with StyrofoamTM Brand XPS Insulation could be as much as 19-32 times the carbon emissions associated with its production3, although this ratio will be slightly lower as energy grids move towards decarbonization.

Manufacturers, such as DuPont PBS, are continuously working to improve their products’ energy-saving and comfort-related qualities, while also striving to reduce products’ carbon footprint. You can expect exciting changes to come in the years ahead.

References

  1. Chau, V. V.; Paquet, A. N. An Evaluation of the Thermal Conductivity of Extruded Polystyrene Foam Blow with HFC-134a or HCFC-142b. J Cel Plas 2008, 40, 205-228.
  2. Mazor, M. H.; Mutton, J. D.; Russell, D. A. M; Keoleian, G. A. Life Cycle Greenhouse Gas Emissions Reduction From Rigid Thermal Insulation Use in Buildings. J Ind Eco 2011, 15(2), 284-299.
  3. Estimate is based on installation in ASHRAE climate zone 5 using energy emissions factor associated with natural gas for heating (117 lbs CO2e/MBTU), relative to an uninsulated wall