The growth of renewable energy, especially photovoltaic (PV) rooftops has significantly increased in the past decades. This would lead to a rise in generated energy on the power network. The increase is due to the advanced development of PV cells, PV modules, and inverter technologies, which result in higher generated energy, lower energy consumption, and higher efficiency in streamlining production processes. However, it can allow the potential benefit of such dynamic electricity tariffs. It is well known that electricity pricing varies over time. The electricity tariff will play an essential role in increasing the incentive of the consumer who uses and plans to install PV rooftops. Therefore, this research aims to design, develop and analyze the effects of electricity tariffs on the optimal PV rooftop installation. Because it can provide subsidies for electricity billing and reduce the carbon footprint, the investment in the PV rooftop will become much more incentive, and the payback period will be shortened; hence, it encourages the consumer to install the system. The electricity tariffs are typically based on the electricity provider, which depends on the area, type of business, and type of consumer. Thus, the research focuses on Thailand’s electricity providers, especially the Metropolitan Electricity Authority (MEA) and Provincial Electricity Authority (PEA), as they are typically supplied in urban and rural areas, respectively. The case studies were based on the Type 1 Residential Service of MEA, Type 2 Small General Service of MEA, Schedule 1 Residential Service of PEA, and Schedule 2 Small General Service of PEA. The results showed that the electricity tariffs directly affected the incentive and the payback period for investment in the PV rooftop.