To reduce CO2 emissions in the residential sector, the installation of high-efficiency energy supply equipment and development of zero energy house are progressing in Japan. It is important to appropriately select energy system configuration, such as the number of installed equipment and capacity when designing the system configuration. There are various studies on the configuration of energy systems. The purpose of this study, we analyze the trends of the relationship between optimal configuration and household characteristics. Then, based on the derived configuration, we evaluate the system configuration from a long-term perspective. We assume a smart residential building consisting of multiple households that introduces photovoltaics (PV) and battery (BT) as common assets and has variations in the number of occupants and demand profile. In addition, we consider various thermal devices, which is a gas-fired water heater (GH), heat pump water heater (HPWH), and solid oxide fuel cell cogeneration systems (SOFC). Deriving the optimal configuration of energy systems over the year is difficult from the viewpoint of calculation load. Therefore, we select 7 representative days for each month and derive optimal configuration such as minimizing CO2 emissions in each evaluation period. Then, we aggregate the results and decide the optimal configuration of the residential building in the target year. As a result, when the CO2 conversion factor for electricity is 0.400 kg/kWh or more, installing SOFC to the few-person household is effective. On the other hand, in the case of the many-person household, the SOFC installation effect is lower than the HPWH from the viewpoint of CO2 emissions.