Australia is receiving an average of 58 million PJ of solar radiation per year, which is about 1000 times larger than its total energy generation. Roof-top solar photovoltaic (PV) systems alone can supply a phenomenal fraction of the nation’s total energy. The architectural design and orientation of roofs have considerable impacts on the energy efficiency of roof-top solar PV systems. These aspects, however, have received scant academic attention within the literature. To address this knowledge gap, this research seeks to increase the energy production of roof-top solar PV systems through roof design. The energy generation of roof-top solar PV systems is modelled using Helioscope software, and then validated using real-time monitored data. Based on the verified model, the impact of different tilt angles and shading from surrounding obstructions upon energy generation are analyzed in detail. To ground the research in practical terms, the aesthetic design of five typical roof design patterns (including flat, shed, gable, hip, and butterfly roof) are explored to compare the energy generated from solar PV systems fitted to each design. Findings indicate that: (1) the simulated energy generation from the solar PV system is close to the monitored data, with equal annual generation; (2) the shading of surrounding obstructions can reduce the energy generation of roof-top solar PV systems considerably, where up to 24% energy loss is reported; (3) the optimal tilt angle is about 35°, which is close to the latitude angle of the studied location; and (4) the shed roof design provides the maximum potential for solar energy generation when compared to that of other roof design patterns. The energy generation variation of other aesthetic roof patterns   is also presented, providing support for informed decision making on the roof design. This study contributes to the field through improving the energy production of roof-top solar PV systems based on roof design along with considering aesthetic concerns. Novel insights generated will be beneficial for researchers and government policy makers alike; the work also introduces simulation-based methodological approaches for practitioners who seek to improve the energy generation of roof-top solar PV systems.