At one time, the idea of a zero net energy building seemed like science fiction, similar to flying cars and jetpacks. Yet, as of 2016, there were 332 zero net energy verified buildings in North America, according to the New Buildings Institute. As building owners demand more energy-efficient buildings, and codes become more rigorous, this number will grow, as will the requirements for building insulation.

An examination of building code trends indicates steady movement toward an eventual future of all zero net energy commercial buildings. U.S. Dept. of Energy (DOE) data show that the energy use intensity (EUI) of commercial buildings is nearly 50 percent less under ASHRAE 90.1-2013 than it was under ASHRAE 90A-1980. That trend has accelerated over time, with EUI dropping especially sharply with the adoption of the 2001 and 2007 versions of ASHRAE 90.1.