CALGreen versus LEED

Alex Spliger

The California Green Building Standards Code (CALGreen) is the first statewide green building code in the country and seeks to establish minimum green building standards for the majority of residential and commercial new construction projects across California.  As the requirements of CALGreen take effect this year, many wonder how the new code compares with other established green building standards, such as the U.S. Green Building Council’s LEED rating system.

CALGreen may be the first green building code formally adopted by a state, but green building standards are nothing new in California. The state has over 1,000 LEED-certified projects, more than any other state in the country. The question is, how will LEED – the established industry benchmark – be affected by the emergence of CALGreen for new commercial buildings?  In the answer lies the future of the green building landscape in the Golden State; and as goes California, so goes the nation.

To address this question, one must look at differences and similarities between CALGreen and LEED in areas such as site characteristics, energy efficiency, water reduction, materials, and the indoor environment. When comparing individual areas within each standard, it’s important to recognize that LEED is a voluntary point-based rating system with four levels of certification. CALGreen, on the other hand, is a mandatory green building code that also includes optional “tiers” for projects seeking to go beyond the minimum level required.    

Both CALGreen and LEED address five main categories relating to new commercial buildings:  site, water, energy, materials and the indoor environment.  Since LEED is a point-based rating system in which projects must achieve at least 40 of 110 possible points, it allows for flexibility and has few mandatory prerequisites. In contrast, all of the measures within CalGreen are mandatory, with the exception of the optional tiers.

One of the main differences between CALGreen and LEED is their approach to energy efficiency.  CALGreen does not require energy efficiency above the Title 24 code minimum, while LEED requires at least 10 percent improvement, and will therefore always be more stringent than CALGreen’s mandatory measures. 

Within the site category, both standards address storm water pollution, bicycle storage, preferred parking for carpools and low-emitting vehicles as well as light-pollution reduction. But unlike CALGreen, LEED emphasizes the location of the site in relation to basic services and public transportation, accounting for the significant environmental impact of automobiles.  Accordingly, a project that meets the basic CALGreen requirements would achieve at least two out of 26 possible points within the site category of the LEED for New Construction rating system. 

In water efficiency, both LEED and CALGreen address indoor and outdoor water use, as well as wastewater reduction.  Within these areas the specific performance benchmarks differ, with LEED being somewhat more stringent.  A project that meets the minimum CALGreen requirements would not necessarily achieve any of the 10 possible LEED points awarded for water efficiency. However, CALGreen also requires water meters, which are not formally addressed by LEED.

When evaluating materials, both LEED and CALGreen address construction waste diversion. However, LEED also takes other factors into consideration such as salvaged, recycled content, regional and rapidly renewable materials. LEED addresses sustainably harvested wood as well. In general, a project that meets the minimum CALGreen requirements would receive at least one of 14 possible points for materials and resources within the LEED NC rating system.

Lastly, in the indoor environmental quality section, CALGreen and LEED focus on similar areas, such as construction indoor air quality, low-emitting materials, air filters, outdoor air delivery, and carbon dioxide monitoring.  CALGreen also accounts for acoustics, while LEED addresses lighting, thermal comfort control, daylighting, and views to the outdoors. In general, projects that meet the minimum CALGreen requirements would achieve at least five of 15 possible LEED points in the indoor environmental quality section.  

In short, CALGreen’s mandatory measures overlap with some areas of LEED, but  overall, LEED requirements are more stringent and cover a broader spectrum of green building strategies, such as daylighting, sustainably harvested wood and site selection.  One might say that CALGreen raises the floor, while LEED raises the ceiling.

CALGreen can only help to promote green building practices throughout the state by requiring all projects to meet minimum measures.  At the same time, it provides a catalyst for encouraging LEED and other third-party rating systems to adapt and improve as state agencies enter the green building standards market to both complement and compete with non-profits such as the USGBC.  As the future of green building in California unfolds one thing is certain: Regardless of which green building standard applies, we will see progress.