In the construction sector, the pursuit of immediate cost savings during the design or building phase—whether through hiring less qualified professionals, using low-quality materials, or modifying construction systems without technical backing—can lead to financial losses and future rework, compromising a building's performance and durability. The Franklin Township Library in Somerset, New Jersey, is a clear example of the consequences of inadequate material choices, particularly regarding energy efficiency and carbon footprint.
During its construction in 2005, the originally specified Kalwall translucent fiberglass-reinforced polymer (FRP) panels were replaced with polycarbonate panels on the roof to achieve an initial savings of $90,000. This seemingly harmless decision quickly proved problematic, resulting in significant operational challenges.
Since the polycarbonate panels were not specified for this particular use and lacked proper technical analysis, they caused excessive solar heat gain, overloading the library's HVAC system. Originally designed for a 40-ton capacity with the specified FRP panels, the system required an additional 20 tons to compensate for the inefficiencies of the substituted material. The cost of upgrading the HVAC system alone was estimated at $200,000. Furthermore, over 19 years, the library faced annual energy losses ranging between $50,000 and $60,000, far exceeding the initial material cost savings.
The choice of translucent materials for roofing and façades is crucial in architectural projects that aim to optimize natural light and create bright, welcoming spaces. The ideal material should offer adequate thermal performance, glare control, and a sense of openness to the exterior. Traditionally, frosted glass and polycarbonate have been widely used, but they often present limitations in energy efficiency and durability. In contrast, FRP panels, such as those supplied by Kalwall, stand out for their strength, lightweight nature, and superior thermal performance. Widely employed in translucent façades, sports facilities, and industrial buildings, these panels optimize natural light, eliminate excessive glare, and significantly reduce operational costs.
Beyond financial costs, the decision to replace the panels directly impacted the building's carbon footprint. Operational carbon, which refers to CO₂ emissions from electricity consumption, heating, and cooling, increased significantly due to the overburdened HVAC system. This aspect, often underestimated, accounts for approximately 28% of global energy-related CO₂ emissions. Additionally, embodied carbon, associated with material extraction, manufacturing, transportation, construction, and disposal, must also be considered when evaluating a building's environmental impact. Materials such as concrete and steel are major contributors to these emissions, accounting for roughly 9% of global greenhouse gas emissions from energy use.
To correct the negative impacts of this initial decision, the library underwent a roof renovation, replacing the polycarbonate panels with the originally specified Kalwall translucent FRP panels. These panels now cover over 14,000 square feet (1,300 m²) of interior space, including the adjacent butterfly garden's solar roof, which spans 600 square feet (56 m²). This intervention not only improved the building's thermal performance—reducing energy consumption and operational costs—but also enhanced light quality and occupant comfort.
The new composite sandwich roof panels feature upgraded specifications to maximize efficiency and thermal comfort. The external face has a 0.70 crystal type A finish, while the internal face features a 0.45 white type 25, both designed to optimize natural light diffusion and minimize excessive heat gain. The system was developed with a U-factor of 0.18, utilizing custom Kalcurve® skyroof technology, ensuring superior thermal insulation and significantly contributing to energy savings. Additionally, Kalwall panels hold an Environmental Product Declaration (EPD) certification, ensuring transparency regarding their environmental impact and energy efficiency.
The Franklin Township Library case underscores the importance of considering not only upfront costs but also the long-term environmental and operational impacts when selecting materials for a project. Investing in materials with lower embodied carbon and higher energy efficiency is essential for reducing a building's carbon footprint and aligning with global sustainability goals. Moreover, architects and engineers must conduct energy simulations and review environmental certifications before making modifications to the original design to prevent costly and environmentally detrimental mistakes.
