Green Star uses a prescriptive method by giving credits for initiatives that are implemented into the design. These credits are translated into points using an internal Green Star weighting system. The total score will give the design a final rating. Depending on the credits utilised, the final environmental performance can vary significantly for the same final rating when a scientific calculation method is used to quantify the results. For example, eTool conducted a study that a 6-star Green Star building can have a performance range from 28% to 77% in greenhouse gas (GHG) emissions1 reduction. The building performance will also vary depending on project type and scale.
Life Cycle Design (LCD) methodology is performance based and the improvement strategies are quantified and prioritised based on their performance for the specific project. LCD provides a greater emphasis on initiatives that deliver real and quantifiable environmental benefits rather than using a prescriptive method. LCD uses a comparative analysis, quantifying and comparing the performance of the proposed design against a code compliant benchmark building of the same function obtain the final result. LCD uses various impact indicators to provide quantitative results.
Example: The overall benefits of solar PV will depend on; the environmental performance of the electricity grid the project is connected to, the impacts associated with embodied carbon (materials, repair, replacement, transport) over the life of the building, efficiency of the system, generation capacity and others. The only way to quantify the real final performance is by running a life cycle assessment of the PV system applied to a specific project.
Posted in: Life Cycle Design vs Green Building Rating