The first of two public comment periods for proposed updates to the USGBC’s LEED rating systems and credits, including LEED for Homes (LEED-H), will close on Jan. 14. The second period will run from July 1 through Aug. 15, 2011, with a projected release of revised LEED requirements set for November 2012. Overall goals of the LEED-H updates will be to streamline the certification process, reduce paperwork, and move toward performance-based criteria. “LEED has always pushed codes,” LEED for Homes technical development manager Asa Foss said during the 2010 Greenbuild conference. “And whenever we stretch the LEED requirements we try to balance how far to go and how fast.” Specific proposed changes to the LEED-H rating system include:
¦ Changing the certification point scale from 136 points to 100 points to align with other rating systems
¦ Weighting credits within their categories to reflect their environmental impact
¦ Updating Energy and Atmosphere credits to meet new Energy Star for Homes Version 3.0 requirements
¦ Requiring all projects to complete Energy Star 3.0 HVAC inspection checklists
¦ Adding 10 new credits including those for trades training, WaterSense Homes certification, solar-ready rough-ins, and HRVs and ERVs
¦ Addressing plug load management.
Perhaps the most significant changes would shift credits from relative performance comparisons like HERS rating levels to what Foss referred to as “absolute metrics” for annual energy consumption. This performance pathway would establish a prerequisite for “Maximum Absolute Energy Performance,” and award credits to “Optimize Absolute Energy Performance.”
This new approach would actually reward design decisions that affect performance in ways that a prescriptive path can’t, and offer fairer comparisons between homes—including existing homes. “The real metric here,” added Foss, “is the total energy consumed.”
Many of the changes to LEED-H that are under consideration by the USGBC have been stimulated in part by new Energy Star 3.0 requirements going into effect this month. Energy Star levels are referenced as baselines in a number of LEED credit practices, so changes to Energy Star would by definition affect the LEED Rating System. Energy Star 2011 provisions include new building science–based requirements, measures to reduce thermal bridging, a change to a variable HERS threshold that will lead to lower HERS ratings, and new checklists covering Thermal Enclosure System, HVAC System Quality Installation, and Water Management.
Visit www.usgbc.org and click on “LEED Rating System Draft” to review proposed changes and submit comments.