Ten years after the first LEED certification was issued, there’s no doubt that sustainability has become entrenched in building design. But questions linger about how much green initiatives impact energy efficiency.
An analysis coordinated by the ACEEE examines credits in energy efficiency across successive LEED for New Construction (NC) rating versions. The findings confirm that the latest NC designs are 29% more efficient than ASHRAE 90.1-2007.
The LEED NC v2.1, v2.2, and v2009 rating systems account for 9,026 certified commercial projects totaling over 851 million square feet in the U.S. Each of these included the Energy & Atmosphere category, which awards points on a sliding scale by the percentage documented efficiency improvements over the ASHRAE 90.1 baseline.
Results showed credit achievement in the Energy & Atmosphere category has increased over time – the mean LEED EA category credit achievement in 2006-2008 was 6.4 points and increased to 7.0 points during 2009-2011.
LEED NC v2009 projects demonstrate an average improvement of 29% over 90.1-2007, which is a significant advance in design efficiency compared to the roughly 20% savings seen in NC v2.2 using the 90.1-2004 standard.
The 2009 version now requires projects to demonstrate a 10% design improvement over the newly updated ASHRAE 90.1-2007 before achieving points for energy efficiency under the EAc1 credit, which will spurn even greater efficiency gains.
Learn more in The LEED Plaque Unpacked: What a Decade of LEED Project Data Reveals about the Green Building Market at accee.org.