A method for searching the optimum shading coefficient for given window is presented, taking into consideration the energy consumption of the building for heating, cooling and daylighting. A comparison between the performance of different shading devices like glazing materials, external and internal shading, is accomplished. The method is demonstrated on a case study for which diagonal shading devices were found to be the best solution. The problem of optimal window shading arises in regions with hot climates. In many cases, energy saving in summer is dominated by the shading parameter more than by other design parameters, due to the reduction of cooling load during the summer. On the other hand, window overshading reduces the amount of daylighting. Also, the additional artificial illumination may increase significantly the cooling load in summer. The present work analyses the climatic and light conditions of the different options in solar control devices for windows. Taking in consideration the consumption of energy and the comfort of the occupants, the variants used in the diagnosis are studied using scale models and comparative with computer available programs, with the principal aim to demonstrate in didactic way the concepts used to the students of the career of architecture.