Abstract—Buildings consume a large amount of energy in Australia. To assess the sustainability performance, including energy performance, of buildings, Australia has developed several evaluation systems with the main ones being Green Star, NABERS, NatHERS and BASIX. Industry practitioners have a certain level of freedom to choose from these evaluation systems to evaluate the sustainability performance of their buildings. However, there is a lack of systemic comparison among these evaluation systems in general, and between the ways that the energy performance of buildings is assessed by these systems in specific. This study provides a systemic comparison between these four main evaluation systems regarding their approaches to assess the energy performance of buildings in Australia. The results show that these systems use different assessing methodologies, namely indicator-based or simulation-based methods, to assess different types of buildings based on data from different sources. These differences reveal the possibility of merging these existing systems to propose a new system that could better assess the energy performance of buildings in Australia.