In this paper, we proposed a simulation methodology for evaluating the performance of CO2 Emission (CE) and Investment Value (IV) of Green Roof shape Integrated Photovoltaic System (GRIPV) of a Wooden Detached House using GA. CE and IV acting as evaluation indices were studied. It is an analytical comparative study of searching for efficient GRIPV by maximizing IV and minimizing CE simultaneously. Three typical locations in Japan are taken into account: Sapporo, Tokyo and Naha. We achieved optimal Pareto curve of each location.