In the quest for energy-efficient buildings, windows have long been a double-edged sword—offering natural light and views but also contributing to thermal discomfort and energy waste. A groundbreaking study published in the *Journal of Daylighting* (translated from Spanish as *Journal of Daylight*), led by Maureen De Gastines of the Instituto de Ambiente, Hábitat y Energía (INAHE) in Mendoza, Argentina, sheds new light on how Solar Control Films (SCFs) can enhance year-round thermal comfort, particularly in high solar irradiance climates.
De Gastines and her team developed a solar-adjusted analytical framework that evaluates indoor thermal comfort by integrating dynamic shortwave solar radiation effects, spatial zoning, and occupant behavior. This approach is a significant departure from traditional comfort assessments, which often overlook these critical factors.
The study, conducted in a cold arid (BWk) climate, found that absorbing SCFs with solar transmittance values between 0.22 and 0.40 can reduce heat-related discomfort by a staggering 70–90% across all orientations. Even more impressive, the reflective film completely eliminated heat-related discomfort under all studied conditions. “The reflective film performed exceptionally well, particularly in orientations where heat discomfort is most critical, such as north and northeast,” De Gastines explained.
However, the researchers noted that while SCFs increase cold discomfort hours, the overall impact remains beneficial. By integrating hourly clothing adjustments into the framework, the team reduced predicted warm discomfort by more than half and cold discomfort by 28% on average. This dynamic approach offers a more realistic evaluation of occupant experience and highlights the importance of adaptive behavior in thermal comfort assessments.
The choice of metric also played a crucial role in performance rankings. For average Thermal Comfort Availability (TCAmean), the reflective film excelled in north, northwest, and west orientations, while absorbing films performed best in east and northeast. For time Thermal Comfort Usability (tTCU10-90), the reflective film outperformed other options across most orientations, doubling hours with 90% of the space in comfort conditions in north and northeast orientations.
Beyond improving thermal comfort, SCFs also reduce overheating near windows and homogenize thermal comfort across spaces, enabling optimized HVAC operation. This can lead to significant energy savings and reduced carbon emissions, making SCFs an attractive option for the energy sector.
The study’s findings have profound implications for retrofitting strategies and climate-responsive design. By integrating solar radiation impacts and dynamic, spatially resolved metrics into thermal comfort assessments, architects, engineers, and policymakers can make more informed decisions about building design and retrofitting.
As the world grapples with the challenges of climate change and energy efficiency, this research offers a promising path forward. “Our work highlights the potential of SCFs to enhance thermal comfort and energy efficiency in buildings,” De Gastines said. “By considering solar radiation impacts and occupant behavior, we can create more sustainable and comfortable indoor environments.”
This research is a significant step forward in the field of building science and energy efficiency. As the construction industry continues to evolve, the insights gained from this study will undoubtedly shape future developments, paving the way for more sustainable and comfortable buildings.