Polyiso CI
Meeting Building Energy Efficiency Standards
by Justin Koscher, President of the Polyisocyanurate Insulation Manufacturers Association
As global efforts to decarbonize intensify, buildings hold immense potential. The International Energy Agency (IEA) reports that operations of buildings account for 30% of global final energy consumption. Because of their high consumption, adopting forward-thinking strategies to improve performance in new and existing buildings can offer unparalleled opportunities for energy savings. Underlining this point, an IEA study suggests that buildings account for nearly 41% of global energy savings potential by 2035.
Recognizing this opportunity, federal, state, and local governments are adopting stringent energy codes and building performance standards that require new and existing structures to meet sustainability targets, invest in energy-saving improvements, and reduce climate impacts over time. For example, California’s Building Energy Efficiency Standard, Title 24, which includes CALGreen, is updated every three years to meet the state’s goal of all new and existing residential and non-residential construction to achieve Net Zero Consumption by 2030.
As similar performance implications become mandatory and widely adopted across other states, a key approach to reducing energy consumption could be to target a building’s highest energy-consuming activities. Of note, the U.S Energy Information Agency’s Commercial Building Energy Consumption Survey indicates space heating alone accounts for 32% of energy use in all United States commercial buildings.
The building envelope can play an important role when it comes to prioritizing building energy performance as it serves as the physical barrier between interior conditioned spaces and external environments. To make strides in the right direction, Western architects can adopt advanced building materials and strategies when constructing new buildings or completing building envelope alterations to minimize heat transfer and decrease whole-building energy consumption.
Prioritizing Energy Efficiency
To meet energy efficiency objectives, Western architects have traditionally specified insulation into wall cavities to achieve the desired R-value or as required by code. These methods typically place insulation between framing members, such as wood or steel studs. While compliant with traditional energy code requirements, this approach creates individual bridges for thermal conductivity that provide a path of least resistance for heat to escape or enter the building during the summer. Even in otherwise insulated buildings, thermal bridging can account for up to 30% energy loss.
Specifying continuous insulation (CI) as part of the wall assembly can help mitigate heat transfer. Unlike traditional methods, CI covers entire opaque surfaces, alleviating thermal bridging and ensuring a more energy-efficient, code-compliant building. Western architects aiming to improve building performance can utilize proven solutions like polyiso continuous insulation. With one of the highest R-values per inch, Polyiso CI has superior thermal resistance and effectively reduces energy loss due to thermal bridging.
In application, Polyiso CI improves a building’s energy efficiency while reducing the load on the mechanical systems, leading to lower operational carbon emissions. Depending on the required minimum R-value for opaque wall assembly, climate zone, and thickness of the product used, a wall system with Polyiso CI can help Western architects meet energy code and building performance requirements with limited, or no, cavity insulation.
Minimizing Air Leakage & Condensation
In addition to a building envelope’s R-values, several variables affect energy consumption and carbon emission. Among these, air leakage is one of the leading contributors to energy loss. The United States Department of Energy estimates that air leakage through the envelope is responsible for nearly 6% of energy use in commercial buildings annually.
To reduce energy consumption, minimizing air leakage is crucial. Modern energy codes and performance standards place importance on addressing air leakage and recommend varying levels of airtightness. To meet these requirements, Western architects can use Polyiso CI as part of the building’s air barrier system to mitigate air intrusion. Flexible in design, Polyiso CI with properly sealed or taped joints can serve as an effective air barrier, reducing air infiltration, and exfiltration. In fact, model building codes recognize Polyiso CI at a minimum ½-inch thickness as an air barrier when installed with approved flashing tape or otherwise sealed in accordance with the manufacturer’s instructions.
Another crucial reason to mitigate air leakage is to reduce the risk of condensation. In colder climates such as Alaska or Wyoming, exfiltration can lead to condensation on the interior-facing surface of the exterior sheathing. Similarly, in hot and humid climates like certain parts of California, infiltration can lead to condensation on the outer-facing surface of the exterior sheathing material. Both cases can compromise building performance and increase its operational carbon footprint. Playing multiple roles, polyiso’s closed-cell foam is inherently water resistant, which makes it possible for Polyiso CI to minimize the risk of bulk water intrusion when used as the wall systems’ priority water barrier.
Key Considerations for Western Architects
A versatile solution, Polyiso CI can significantly fortify the thermal envelope, effectively curbing energy consumption and emissions. Elaborating further on the benefits of Polyiso CI, Greg Fantin, Vice President of Marketing at Rmax® Insulation said, “Integrating Polyiso CI in a wall assembly allows the possibility of removing additional elements like gypsum or weather-resistive barriers. With a high R-value per inch and simplified control layers within an assembly, Western architects can thin the overall wall assembly and realize more usable floor area within the existing footprint of the structure while still meeting building emission and performance requirements.”
Beyond wall assembly, roof systems hold significant energy savings potential as the largest component of a typical commercial building’s envelope. While roofs in newer buildings are designed to comply with current code-required R-values, many older buildings fall well short of modern standards for insulation. In such projects, prioritizing roof replacements with code-compliant levels of insulation like polyiso, can greatly enhance a building’s energy efficiency. An independent analysis conducted by ICF International on behalf of the polyiso industry suggests that this strategy can achieve up to a 10% reduction in whole-building energy consumption, depending on the building’s type, size, and location.
By embracing this proven material in the building envelope, Western architects can not only ensure compliance with progressive energy codes and building performance standards such as Title 24 but also be active participants in realizing a more sustainable future.
