Abstract
After evaluating the life cycle of a household photovoltaic power system, based on the payback time of energy consumption, carbon dioxide emission, and cost, we investigated residents' awareness of such systems and the economic incentives related to their installation. Using a questionnaire survey, we asked over 200 residents of Kusatsu City about their awareness of household photovoltaic power systems, to investigate the factors related to installation of the system in the residents' houses . The residents' awareness of energy costs was the most significant factor. Subsidies that enabled recouping the cost in less than 20 years would be sufficient for 67.6 % of residents to install a household photovoltaic power system.
