M10 AM Building Life-Cycle Capacity in the Greening of Buildings and Construction Consideration
Monday, 14 November 2005: 8:00 AM - 11:40 AM in 341-342

(HUM-1117-647081) Towards a Better LEED Scoring System.

Humbert, Sebastien¹, Abeck, Heike^{1, 2}, Bali, Nishil¹, Horvath, Arpad³, ¹ Graduate Student, Dept. of Civil and Environmental Engineering, University of California, Berkeley, CA, USA² Principal Process Engineer, Chiron, Emeryville, CA, USA³ Associate Professor, Dept. of Civil and Environmental Engineering, University of California, Berkeley, CA, USA

ABSTRACT- LEED (Leadership in Energy and Environmental Design) is a building rating system that is growing in popularity. It is composed of 69 credits, each providing 1 point if "implemented" in the building. However, actual environmental benefits each credits provide do not seem to be always of the same order of magnitude: a higher rating does not necessarily equal more environmental friendliness. In this research, benefits and burdens of LEED have been applied to an actual office building in California, and evaluated using a life-cycle assessment (LCA) approach. The impacts of this building are dominated by operation and maintenance, which is dominated by energy consumption and employee commuting, whereas water consumption and waste management have small impacts. The credits that provide the most environmental benefits are the one geared toward green power, reducing energy consumption and commuting, and increasing the recycling/reuse of the structure during renovation. Credits related to water efficiency, waste recycling, building footprint reduction, or recycling content in the furniture appear to provide much less benefits. The main difficulties in this assessment included the evaluation of the effectiveness of credits targeting the reduction of employee commuting, and the actual environmental benefits due to reduced land use. Observations indicate that the benefits of LEED credits are not always consistent with the points assigned. We find that some credits have larger benefits than others. As a correction to the existing LEED system, benefits and burdens have been aggregated in one indicator per credit, and a new scale for the LEED points system has been developed to reflect the actual magnitude of the environmental benefits of each credit. It appears that several credits leading to large benefits are in fact not the ones targeted in practice. This miscorrelation needs to be addressed and corrected in the current LEED rating system.

Key words: Green buildings, LEED, Office building, Life-Cycle Assessment (LCA)