The state of energy efficiency covered in latest ebook

October 12, 2021

The magazine’s series of sponsored ebooks continues with a focus on modern exterior design practices. Photo courtesy Hoffmann Architects

On February 24, 2017, The New York Times ran an article regarding the eventual de-commissioning of the Indian Point nuclear power plant just north of New York city.

According to the article, the governor intends to close the plant by 2021. This raises the question: How does New York state intend to replace the energy the plant created so they can still meet power demands?

As it turns out, they do not; not entirely. The article goes on to cite a report that determined New York’s best option is not finding alternative sources of power, but to follow states like Massachusetts and Rhode Island in enacting programs to reduce energy use.

New York is not alone in applying this calculus to energy policy, and the cumulative effect such decisions have on the built environment is significant. In 2010, the required insulative value for a new, low-sloped roof on a commercial building in climate zone 4  (the region that includes New York City) was R-20. Today, the 2018 International Energy Conservation Code (IECC) requires that same roof to have a value of R-30—a 50 percent increase. For windows, the change has been even more dramatic. In 2010, new fixed windows needed an R-1.82; today it is R-2.63—a 45 percent increase. Further, while similar values for exterior walls have remained largely the same, the method of assessing performance has changed greatly.

The 2018 IECC is the latest in a line of increasingly stringent regulatory requirements. While it is not necessarily a response to, these regulations certainly support a shift in policy being adopted by states like New York that seek to meet energy needs in part by reducing usage.

Today, the path to energy code compliance can be nuanced and complicated, requiring knowledge not just of standards and materials, but a basic understanding of scientific concepts like the laws of thermo- and fluid-dynamics. Stricter requirements now bring designers into potential conflict with competing codes on issues like combustibility and structural stability. It is, of course, unlikely this trend will ever reverse itself. Instead, the requirements for energy performance will simply continue to become more stringent and paths to compliance will be more complicated. With all of this in mind, an overview of the 2018 IECC and the science behind it might be helpful. To simplify things, the discussion in this article will be limited to commercial buildings.

This article appears in a collection in Modern Exterior Design Practices, a free, downloadable resource. To get your copy in either pdf or digital edition, visit

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