PV system is an eco-friendly option to meet the need for energy due to its lower carbon footprint when compared to the fossil-fueled power plants. In this research, we performed techno-economic and regulatory impact analysis on a rooftop PV system on a mosque in Purworejo, Indonesia under a net metering mechanism. The use of PV system on the mosque rooftop can reduce its entire carbon emission from its annual energy usage, which equals to 4 tonnes of carbon dioxide equivalent. However, the economic feasibility of the PV systems, measured by the NPV of the electricity bill saving, shows negative values for all PV system configuration, defined by the type and number of panels. This low financial attractiveness is resulted from several unsupportive regulations: the subsidized electricity tariff, the minimum grid electricity usage limit and the less rewarding net metering scheme. The abolishment of minimum usage limit incurs the greatest increase of NPV to the PV system that is designed to entirely supply the load demand. While the implementation of higher electricity tariff incurs the highest increase of NPV for the PV systems with partial supply scenario. This study shows that at the current electricity tariff, costs of components, and the implemented regulations around the adoption of PV system, it is financially unfeasible to install a PV system on the mosque rooftop.