Net-zero-energy buildings and homes, which rely on high-performance glazing to reach efficiency goals, are currently a small, specialized niche in the overall North American housing market. However, it’s one that’s starting to show solid growth, according to a new report from the Net-Zero Energy Coalition.

The group found that that the number of multifamily and single-family homes that meet the net-zero standard grew by 33 percent from 2015 to 2016.

Today, there are more than 8,200 net-zero units across the U.S. and Canada. In 2016, most new net-zero buildings (61 percent) were part of multifamily structures. Additionally, the report said the number of projects in the planning stage rose by 81 percent, from 408 in 2015 to 741 in 2016.

“Momentum is steadily building in the residential ZE (zero-energy) sector, and will continue to accelerate,” the report says.

The report finds that state and local governments are driving the adoption of net-zero-energy construction, especially in California, where the number of net-zero units rose by 104 percent in 2016.

Net Zero and Windows

The Department of Energy says supplying power to buildings accounts for 41 percent of carbon emissions in the United States. Net-zero-energy buildings are those in which energy use is reduced by 60 to 90 percent through efficiency improvements. Because the building envelope plays a major role in reaching that goal, the growth of net-zero-energy construction could present a major business opportunity for window companies, according to Steve Selkowitz, group leader of the Windows and Envelope Materials Group in the Building Technology and Urban Systems Division at Lawrence Berkeley National Laboratory.

Window technologies for achieving net zero including building integrated photovoltaics (BIPV) for providing electric power and adaptation of “smart” technologies in addition to maximizing the efficiency of glazing and components.

“The ideal [would be an] integrated approach to façade/lighting/HVAC building systems to achieve optimum energy efficiency and comfort,” Selkowitz said during the American Architectural Manufacturers Association’s Western Regional Summit in Phoenix in February. To achieve that kind of integration would require advances in building envelope insulation, intelligent control systems, and new delivery models to bring developments to the market faster and more reliably.

A high-performance building envelope would involve components such as insulating technologies to achieve very low U-factors, the active management and optimization of sunlight, dynamic daylight redirecting systems and ventilation technologies that employ thermal capture. Selkowitz mentioned several that are now in development or on the market, including “thin lightweight triple” (TLT) glazing, which reduces the weight of highly energy-efficient windows and allows them to be used in a greater number of applications.

Integrated, responsive systems would also encompass mechanical shading devices, passive control of solar gain through photochromic or thermochromic glass, and active control through glass employing liquid crystal, suspended particle display (SPD) and electrochromic technologies.

Selkowitz said the net-zero-energy challenge will only be met by balancing people, policy, technology, processes and the market.

“Think big, start small, act now,” he said.