Daylight Redirecting Technology

The Challenge: Acquiring Reliable Data on Daylighting Products

Innovative daylighting and shading technologies such as sunlight-redirecting films can significantly reduce energy use for cooling and electric lights, yet commercial building operators have been slow to adopt them. Without independent evidence of how products perform in the real world, building managers can be understandably reluctant to install them.

PG&E and other California utilities can help accelerate market adoption of these technologies by offering financial incentives to building owners and design teams. But before PG&E could decide on the types of daylight-redirecting products to include in its rebate programs, it needed to verify which of them could deliver measurable energy savings without sacrificing indoor environmental quality and occupant comfort. Beyond that, the utility needed a detailed understanding of any real-world factors that could undercut product effectiveness.

The Solution: FLEXLAB®

PG&E commissioned the U.S Department of Energy’s FLEXLAB® facility at Lawrence Berkeley National Laboratory to conduct a full-scale monitored study of specific daylighting technologies. Researchers evaluated four daylight-redirecting technologies over a six-month period, assessing energy savings, comfort and indoor environmental quality. FLEXLAB delivered concrete, third-party measured evidence of how the products perform in real-world scenarios. This vital analysis enabled the utility to make more informed decisions when constructing program interventions that would support technology adoption in the market.

The Bottom Line: Daylight Redirecting Technologies Can Save Energy

Several manufacturers have introduced products designed to bounce sunlight across an indoor space. These daylight-redirecting technologies promise to boost interior natural light while reducing the need for artificial lighting. Some of these are thin-film window coatings with microscopic features that redirect the sun, while others are automated, motorized upper-window blinds combined with automated lower-window roller shades. Researchers at FLEXLAB® put these systems to the test and were able to verify up to 63% energy savings, giving PG&E the context it needed to design the right incentives for consumers. FLEXLAB's unique facilities enable insights and recommendations for technologies that will be essential to meeting California's zero net energy goals for buildings.


Download the full case study here: Building Envelope Daylighting