The authors installed vertical blinds outside glass windows and sprinkled mist over the space between the glass and the blinds, presuming that mist sprinkling would reduce the temperature of the space and that dampened blinds and glass would produce evaporative cooling of their surface. We also assumed that the installation of exterior blinds would boost the effectiveness of solar radiation shading and evaporative cooling. The blinds can be operated manually not to spoil the view. Tests were conducted both at a mock-up with windows facing south about two square meters and at an experimental building about 165 square meters. The test results show that energy can be saved by about 52 percent.