Originally published on March 26, 2021 by BNP Media through the Building Enclosure Blog.


When it comes to operational energy efficiency, the building design and construction industry continuously raises the ceiling through myriad collective avenues including the increased stringency of volunteer rating systems, monitoring-based commissioning, verified zero energy buildings, and much more.

However, in order to transform the building sector toward a low/no-carbon future, our minimum standards for energy performance must be improved as well. The floor must be raised along with the ceiling.


Raising the ceiling on energy performance

When he issued the 2030 ChallengeAIA Gold Metal awardee Edward Mazria, FAIA, effectively advocated to make the 2003 Commercial Buildings Energy Consumption Survey (CBECS) the baseline by which to measure our progress. The survey is comprised of data collected in 2000. In effect, building energy performance measured in the year 2000 is the baseline.

In order to meet the 2030 Challenge, all new buildings and major renovations shall be carbon-neutral by 2030 – meaning the buildings do not require fossil fuel greenhouse gas-emitting energy to operate. Today, the goal of the challenge is foremost pursued through energy conservation strategies. It is called a “challenge” for a reason. According to the latest AIA report, the collective action of the several hundred leading U.S. design firms formally signed to pursing the AIA’s 2030 Commitment achieved an all-time high in whole building predicted energy use intensity (pEUI) reduction relative to the 2003 CBECS – averaging a 49% improvement across all projects.


Energy codes can raise the floor

At the other end – back to the floor – we have our minimum energy performance standards established by codes.

How far beyond the year 2030 might zero energy buildings become a minimum standard through our building codes? The answer may surprise you.

Two regularly-updated documents that commonly serve as models, or templates, for state energy codes are ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings and the International Energy Conservation Code (IECC). Both model documents are becoming more stringent as a growing number of states are looking to drive their building stock toward zero energy performance – i.e., consisting of buildings that produce as much energy as they use over the course of a year, with performance achieved through energy efficiency and renewable energy technologies.

According to the Pacific Northwest National Laboratory and the New Buildings Institute, the most recent editions of ASHRAE Standard 90.1 and the International Energy Conservation Code (IECC) are nearly 50% more efficient than they were in 2000. Even an archaic state energy code based on ASHRAE 90.1-2007 is about 30% better than the 2003 CBECS baseline. That is not insignificant.

Moreover, if we draw linear trendlines and extrapolate to 100% reduction in net energy consumption over the 2003 CBECS baseline, both ASHRAE 90.1 and IECC will establish a zero site energy model standard between 2035 and 2040.

If we have the collective resolve to raise the floor along with the ceiling for building energy performance, then we may be about halfway through a transformative journey that will realize zero energy buildings as a minimum standard for all building projects. The potential benefits of doing so for energy security, infrastructure endurance, environmental impact, and community resilience would be enormous.

Figure 1: Predicted energy use intensity (pEUI) reduction in building energy codes (2000-2019). Image by Daniel Overbey. Adapted from Fuertes, G. et al. (2020).