Introduction of clean or high-efficiency energy systems that are called eco-energy system such as photovoltaic/solar heating/wind power system and cogeneration system is important, since the rise of energy price and a scarcity of fossil fuel are feared. However, suitable design and operation of eco-energy system were not easy for energy system users, because measurement of energy demand and weather data were needed. The supporting tool “EcoTOP” that suggests suitable design and operation to the energy system users and their facilities at any location in Japan was developed and evaluated.