A team of material scientists from the US Department of Energy’s Lawrence Berkeley National Laboratory has engineered a spray-on nanocrystal coating that uses electricity to control how much light or heat passes through it—and has partnered with a “smart window” startup from California to bring it to market. The team claims unprecedented regulation of both visible and infrared light, including effectiveness after 2,000 test runs—and “huge implications” for residential and commercial energy efficiency.
The spray can be used on existing windows, meaning it’s possible to enhance performance without losing any of the resources already invested in a building’s infrastructure. As a nano-scale spray, it’s quite thin and presumably requires less material than other films—and certainly less than shades, blinds and other add-ons used to control light or heat entering a building. In addition, the product packs a one-two punch by combining two functions, light and heat control, into a single material.
Shifting from conventional to high-performing materials that use far fewer resources opens exciting opportunities to optimize performance through dematerialization. A short blog post like this one from Wired magazine is meant to excite and spark interest—to evoke the possibilities of a new material as a true game-changer. But beneath the surface of glowing potential, what is unspoken or omitted? For an environmental designer who specializes in materials that deliver maximum performance for minimal resource consumption, it is important to approach the technology with caution, and evaluate its larger implications.
At a basic scientific level, consider the properties of the material: this particular innovation is not going to alter the inherent insulation properties of glazing, for example. For a transparent coating such as this, it might be desirable to block intense sunlight and decrease heat infiltration during the summer—in some regions more so than others—but in the winter, excessive glazing, combined with the limited insulation value of glass, might cause substantial heat loss—again, more significantly in some climates. During winter, an over-glazed building envelope will still have heat loss, even with this coating, and additional strategies will be needed to maximize building energy performance. It is essential to understand performance over the course of the day, across changing seasons, and over time.
With respect to its performance over time, the product’s testing results are promising—2,000 test runs and it’s still going strong. But it is unclear under what conditions the technology has been tested, and whether it has shown endurance under a range of normal and extreme weather and climatic conditions. The rigor of analyses and quantitative data is critical for a complete evaluation.
Then there is the reality that this is not the first—or the last—material in development or on the market to promise revolutionary gains in efficiency. How well does this product perform relative to traditional or conventional materials, as well as other innovative solutions? It may help to think from the perspective of limited resources. This nano-scale coating has the potential to optimize temperature regulation—and reduce heat loss—using fewer resources than other technologies.
In addition to considering a product or technology’s performance as a material, there is its environmental impact. This analysis takes into account product lifecycle and the amount of resources embedded in it, as well as whether the material, its components and its manufacturing process comply with standards for environmentally responsible design, such as those outlined in LEED. Finally, as part of a cradle-to-cradle approach to materials, the product should be evaluated for its ability to be recycled.
Of course, there’s the practical side, and whether it will pass the test of feasibility. Are the cost, ROI and replacement value justifiable—for a predictable level of performance? And is it something that a client is likely to invest in?
It’s easy to get excited about new innovations coming to market; the challenge comes in evaluating whether those innovations truly deliver higher performance. Using a resource perspective and considering how the innovation optimizes performance—and saves resources—while itself, using fewer resources—is an effective approach that yields new insights in the process.
- Ray Ho Environmental Designer at Atelier Ten.