Minimising the energy performance gap in Australia's commercial buildings: Energy modelling practice, process, and performance

Evidence suggests that energy modelling with a 'design for performance' approach and Commitment Agreement has reduced the energy performance gap (EPG), primarily in Australia's prime office sector. Yet no research has documented the energy modelling practices and processes employed across the full spectrum of commercial building types in the country; what are the factors driving different types of energy modeling? And what are the challenges and opportunities stakeholders face? This study fills this research gap by surveying energy modellers and building operations teams, groups whose insights have been rarely considered up to now. The results show a marked difference in energy modeling practices between prime offices, mid-tier offices, and other commercial buildings. For instance, compliance-based energy modelling makes up 85% of modeling in non-office buildings, but only 53% in office buildings, and 49% in premium offices. The practice of engaging energy modellers throughout design and operational stages and designing to a specific operational energy performance target are also more prevalent in the office sector, than in non-offices. Energy modellers note how an inadequate scope of engagement and design uncertainty are the two greatest challenges they face in tackling the EPG, and call for energy monitoring and benchmarking, tuning and commissioning, better collaboration and education. The conclusions suggest that policymakers should explore mandating operational performance targets at the design stage, along with performance disclosure in operations, and encourage building owners to perform ongoing benchmarking, monitoring, and tracking of operational performance to reduce the EPG across the broader commercial sector.