In the case of ventilated double skin facades, good management of shading devices and rational use of the ventilation channel are the two most effective ways to reduce the penetrating undesirable load inside interior spaces, especially during warm periods. This paper examines the effect of solar radiation, incidence angle and slat angle on the thermal properties, as well as, the solar transmission into the interior environment for a double skin facade equipped with a venetian blind. In addition, the ventilation efficiency was examined as a function of material emissivity, inlet air flow rate and inlet air temperature. To complete this operation the CFD code, FLUENT 6.3, was used with a realizable k–ɛ turbulence model. In order to solve the radiative transfer equation and to quantify the solar and thermal radiation, the discrete ordinates (DO) radiation method was implemented using a two-band spectral model. It was concluded that, the solar transmission is influenced by the solar radiation, the incidence angle, the slat angle and the material emissivity. The results showed that, when the slat angle exceeds 60°, the heat flux transmitted reach minimum values. The results indicated also, that the dynamic insulation efficiency, ɛd is independent of the ventilation strategy when θ>75°, and its assessment is important, when the incidence angle is 0° and the slat angle is 85°. Thus, the ventilation channel is necessary when the solar radiation incident on the exterior glazing is maximal and the slat prevents that the solar radiation penetrates into the interior environment.