Automated insulating window shades can cut energy consumption by about 25% and may recoup the cost of installation within three to five years, according to a landmark study conducted by Illinois Institute of Technology researchers at Willis Tower.
The study, funded by ComEd, showcases a promising path for sustainability and energy efficiency in architectural design.
Temperature regulation typically accounts for 30-40% of the energy used by buildings in climates similar to Chicago. The research team, led by assistant professor of architectural engineering Mohammad Heidarinejad, focused on the role of window shades, which are often overlooked in energy-savings solutions.
Dramatically reduce energy consumption
The findings underscore how insulating window shades, when connected to an automated control system, can dramatically reduce energy consumption in both heating and cooling seasons.
Heidarinejad says addressing energy waste in standing buildings is a major problem.
"If you're designing a new building, you have a lot of freedom to look at new technologies that save on energy consumption, but for existing buildings, you have limited options," says Heidarinejad.
The study was conducted over a ten-month period in collaboration with Parata Solutions LLC and Amatis Controls at the Equity Office at Willis Tower, a building with single-paned windows and a high window-to-wall ratio. Three control strategies for Parata's patented insulating shades were tested: fully manual control, a predefined schedule, and a sensor-based system considering factors such as outdoor conditions and room occupancy.
The findings were impressive, indicating a 25% decrease in energy use during both heating and cooling seasons with the use of the motorised shades. Even more significant was the positive response from office users, with 80% expressing preference for the new shades over the old blinds.
Christopher Nurre, CEO of Parata Solutions LLC, praised the collaboration with Illinois Tech.
"Working with Mohammad Heidarinejad and his team at Illinois Institute of Technology was a game changer for our company," says Nurre. "Their rigorous field measurements helped confirm the efficacy of our shade system to drastically reduce energy use while offering a solution that occupants and building owners prefer over the incumbent."
Sustainable architectural solutions
The study not only contributed to sustainable architectural solutions but also served as a real-world learning experience for Illinois Tech students involved in the project. Heidarinejad noted the importance of students learning to collaborate on real projects.
"We had students doing instrumentation, data collection, and modelling, and their results were implemented in the actual build study," says Heidarinejad. "It was important for students to learn how to collaborate on a real project."
Further research is planned to explore the effectiveness of these innovative window shades under different conditions, such as in buildings that use natural gas, in different climates, or with windows facing different directions.
Brent Stephens, a co-principal investigator on the project and the Arthur W Hill Endowed Chair in Sustainability, highlighted how this innovative, immediately applicable research aligns perfectly with Illinois Tech's mission.
"In addition to the exciting findings of energy savings and payback period, this project served as a perfect example of the type of industry-relevant research we enjoy – combining field measurements and computer simulations to evaluate a unique strategy to save energy in one of the most famous buildings in the world," says Stephens.