This study explores the feasibility, challenges, and opportunities of integrating photovoltaic (PV) systems into heritage buildings situated in the hot and arid climate of Kashan, Iran. A total of 91 heritage buildings, representing a range of roof dimensions and courtyard typologies, were examined to estimate potential PV energy production and projected energy consumption under a hypothetical hotel conversion scenario. The core of the quantitative analysis is based on electricity consumption and PV energy production data collected in 2023 from a case study involving a historical building retrofitted with a rooftop PV system. The results indicate that buildings with a single courtyard and two adjacent facades exhibit the most stable energy balance performance. Furthermore, the analysis identifies a clear inverse relationship between roof area and the self-sufficiency ratio. Smaller buildings tend to show minimal energy deficits and, in some cases, operate as positive energy buildings. Overall, the study reveals that heritage buildings in Kashan possess considerable potential for solar energy production, with a combined estimated annual generation of approximately 3,675.1 MWh of clean energy. This finding highlights the strategic value of heritage buildings in advancing solar energy deployment, emphasizing their role in urban decarbonization and the sustainable transformation of historic city centres.