PURPOSE: To obtain an economical equalization of temperature distribution in the building by a method wherein movable energy is generated in a heat transportation fluid by solar energy incident into windows on the sunshine side, the movable energy functioning to transport the solar energy to the part in the building where the sunshine does not reach or the temperature is relatively low.

CONSTITUTION: In the window 2 on the sunshine side of the building, a solar energy absorbing part 4 is constituted and connected to a heat discharger 6 on the shaded side through a circulation pipe 5. Within the circulation pipe 5, a coolant such as fleon or the heat transportation fluid such as bline is filled, and a check valve 7 is interposed in a rising part on the sunshine side. When the sun beams are made incident into the window 2, the heat rays thereof is absorbed by a heat ray absorbing glass 9. The heat ray absorbing glass 9 of high temperature heats the air within spaces S1 and S2 defined between outer and inner glasses 8 and 10 so that a rising airstream is generated. By this, the heat transportation fluid in an upper frame member 11 is heated through fins 16. The heat transportation fluid thus heated is made to discharge heat by a heat discharger 6, thereby heating rooms on the shaded side.