BELS is a third-party certification in Japan which represents energy-saving performance of buildings. Real estate companies are required to display energy-saving performance of buildings based on the Improvement on Energy Consumption Performance of Buildings Act (“Building Energy Efficiency Act”) after April 2016. BELS is evaluated based on the guidelines for display of energy saving performance for buildings which the display method is defined. The evaluation is represented with seven-star ratings (from no star to six stars) after April 2024 while it was represented with five-star ratings (from one star to five stars) before April 2024.
Net Zero Energy Building (“ZEB”) is a building that aims at zero energy balance with considerably reduced annual energy consumption by saving as much energy as possible via better heat insulation, solar shading, natural energy and high-efficiency equipment, coupled with creating energy by photovoltaic power generation (or other energy generating methods), while maintaining a comfortable environment. Since the Building Energy Index (BEI), which is used for BELS evaluation, is also used for ZEB evaluation, it is possible to display ZEB evaluation in BELS evaluation. ZEB evaluation can be indicated with four levels, "ZEB," "Nearly ZEB," "ZEB Ready," and "ZEB Oriented," depending on the zero energy achievement status.

For details about BELS and ZEB, please refer to the URL below.

• BELS (Japanese only)
• ZEB (Japanese only)

CASBEE (Comprehensive Assessment System for Built Environment Efficiency) is a comprehensive rating system provided by the Institute for Building Environment and Energy Conservation (IBEC), a non-profit organization supervised by the Japanese government, which assesses and evaluates buildings' environmental functions based on various factors including environmentally friendly construction materials and workplace comfort/amenities, and how the building complements the local community and environment. CASBEE Certifications are based on a five-scale system ("Rank S (excellent)," "Rank A (very good)," "Rank B+ (good)," "Rank B- (slightly inferior)" and "Rank C (inferior)") for buildings that have been completed for more than one year.

LEED (Leadership in Energy & Environmental Design) was developed and operated by the U.S. Green Building Council (USGBC), the non-profit and reviewed by GBCI for certification, and a system for evaluating the environmental performance of built environments (building and urban environments)
In order to receive LEED certification, you must meet the mandatory requirements for each certification system (Building Design and Construction (BD+C), Interior Design and Construction (ID+C), Operation and Maintenance of Existing Buildings (O+M), Neighborhood Development (ND), and Housing (HOMES)), and earn points for selected items. Based on the number of points achieved, a project earns one of four LEED rating levels: Platinum (80+ points), Gold (60-79 points), Silver (50-59 points), and Standard Certification (40-49 points).