Comprehensive Assessment System for Built Environment Efficiency (CASBEE) is a method for evaluating and rating the environmental performance of buildings and the built environment. It is a comprehensive assessment of the quality of a building, evaluating features such as interior comfort and scenic aesthetics, in consideration of environment practices that include using materials and equipment that save energy or achieve smaller environmental loads.The CASBEE assessment is ranked in five grades: Superior (S), Very Good (A), Good (B+), Slightly Poor (B-) and Poor (C).
CASBEE was developed by a research committee established in 2001 as part of a joint industrial/government/academic project. The first assessment tool, CASBEE for Offices, was completed in 2002, followed by CASBEE for New Construction in July 2003, CASBEE for Existing Buildings in July 2004 and CASBEE for Renovation in July 2005. The CASBEE assessment tools were developed on the basis of the following three principles:
-  Comprehensive assessment throughout the life cycle of the building
-  Assessment of the Built Environment Quality and Built Environment Load
-  Assessment based on the newly developed Built Environment Efficiency (BEE) indicator
Space-scale classification and time-process classification
CASBEE is comprised of assessment tools tailored to different scales: construction (houses and buildings), urban (town development) and city management. These tools are collectively known as the CASBEE Family.
As shown in the figure 1, CASBEE-Housing and CASBEE-Building are applied for individual houses and buildings to assess their environmental performance. CASBEE-Urban Development is used to evaluate environmental performance of urban blocks and town development. CASBEE-City evaluates environmental performance on a local government scale. These are assessed based on BEE indicators by CASBEE.
Fig1. Stratified structure of a scale of defined areas for CASBEE assessment
CASBEE was developed in the suite of architectural design processes, starting from the pre-design stage and continuing through design and post-design stages. Corresponding to the building lifecycle, CASBEE is composed of four assessment tools for building scale: CASBEE for Pre-design, CASBEE for New Construction, CASBEE for Existing Buildings and CASBEE for Renovation, and to serve at each stage of the design process.
Fig2. Four tools of CASBEE for building scale corresponding to the building lifecycle