Air-conditioner is going to be set up in public elementary schools. The setting rate reached 64% in Tokyo 23 wards in 2007. The increase of energy consumption is concerned about in case when air-conditioner spreads all over the country. In this study, the forecast of energy consumption until 2030 is illustrated. That is calculated by forecasting the number of classes, the air-conditioner setting rates and air-conditioning load in each 47 prefectures. In addition, the environmental measures scenarios such as natural ventilation and Low-E glass are accounted. It is possible to reduce energy consumption at the level of 1990 by 2030, when all the measures and improvement in COP of air-conditioner are taken.