This paper presents an energy conservation measures prioritization process of a residential Australian building. For this purpose, a simulation model of the building has been implemented and validated based on the information from the energy audit report. Further, a preliminary set of potential energy conservation measures has been identified according to specific information collected during the building survey phase. DesignBuilder software has been used as the simulation tool and yearly energy benefits have been quantified for each intervention. Finally, an economic assessment is conducted based on the most common economic tools (net present value, internal rate of return, profitability index and discounted payback period). As a consequence, a final building performance simulation has been conducted in order to properly quantify the potential energy benefit of the whole retrofit intervention. As results, this study highlights how arduous could be, in certain cases, to achieve a cost-effective retrofit intervention and how economic indexes could bring users to exclude a priori certain energy conservation measures during decision-making process even when these interventions are necessary to improve thermal comfort and energy efficiency.