Expressions of the overall or partial energy performances of buildings, which include intermediate levels (as e.g. heating need), are needed for different purposes: 1) Regulations: to enable the establishment of regulations regarding energy performance of buildings; 2) Decisions: to facilitate decisions or actions in the private or public domain, and 3) Information and communication: on a specific building element, building or building stock; for building designers, owners, operators, users and policy makers. This International Standard focuses on aspects concerning the setting of EPB requirements related to the fabric and the thermal energy balance, thus covering the objectives 1) and 2) above. Table 1 shows the relative position of this International Standard within the EPB package of standards.