Impact of the bonus approach on recertification strategies for LEED-EB v3 office projects in major US metropolitan areas: A case study

Abstract

Leadership in Energy and Environmental Design for Existing Buildings (LEED-EB) version 3 (v3) encourages the recertification of existing buildings by offering them four bonus points (“bonus approach”). This study investigates the influence of a bonus approach on recertification strategies. We analyzed 112 LEED-EB v3 certification-to-recertification office space projects in Washington, DC; Chicago; and New York City. The percentage of average score (PAS) was used to evaluate the difference in certification strategies between (1) gold certification and recertification (with bonus); (2) silver certification and gold recertification (with bonus); (3) gold certification and recertification (without bonus); and (4) silver and gold certification, and gold recertification (combined data from Cases 1–3). In Case 1, recertification showed worse results in the materials and resources (MR), and indoor environmental quality (EQ) categories. In Case 2, recertification showed better results in the water efficiency, and energy and atmosphere categories. In Case 3, certification and recertification showed the same results. We found that recertification of LEED-EB v3 projects with a four-point bonus system resulted in lower results in the MR and EQ categories. This highlights the need to include additional controls in the LEED-EB v3 and v4.1 bonus systems, possibly including a moderate penalty for diminishing achievements in certain categories.