Iiyama city, located at the north of Nagano Pref., is known among the snowy areas in Japan. The removal of snow costs a lot of labors and anxiety to the citizens. The authors suggested a few systems for melting snow on the roof, and examined the performance of those using test devices. The following results were obtained: (1) The snow melting system, utilizing solar energy or geothermal energy, fulfilled the purpose. It was evident from simulation analysis that the hybrid system, using the solar energy and thermal energy of auxiliary boiler, was applicable to the most severe situation. (2) The partial snow melting operation method was more efficient than the perfect melting towards the energy conservation and economical construction.
