A calculation method of transmittance, reflectance and absorptance for Venetian blinds has been organized, taking into account the shapes and reflective properties of slats as well as the condition of incident solar radiation with direct, diffuse and ground reflective components. According to the organized calculation method, a computational program has been developed and calculations have been executed. It is found that the transmittance and reflectance of Venetian blinds vary with slat angle, specular and diffuse reflectance of the slat, profile angle of direct solar component, and amount of each component of the incident solar radiation.
