Rising energy costs, climate commitments and increasing expectations for sustainable development have placed energy performance firmly on the agenda. Without this shared framework, energy assessments become inconsistent, difficult to compare and, ultimately, less reliable. “One of the principal challenges remains the availability of qualified energy auditors”Equally important is the distinction between assessing a building’s theoretical energy performance and evaluating how energy is actually managed in practice. While EN ISO 52000-1 establishes the methodology for calculating the energy performance of buildings, ISO 50001 approaches energy from a different perspective. Energy performance, despite its long-term benefits, can easily become secondary to more immediate business pressures.