A recent architectural current, mainly carried by a desire of building transparency proposed completely glazed facades, released from their function bearing and reduced to the role of envelope. In this case, the only manner of limiting to the maximum the losses in an entirely glazed building is either to build an entirely glazed additional skin, or to use the most efficient possible glazing. The argument justifying the overcost of an additional facade is very often that of the energy effectiveness of the double-skin facade and the improvement of the interior environment. However, this argument must be taken with many precautions. The efficiency of the double-skin depends indeed on many factors such as the type and the use of the building, the orientation, the level of insulation, the proportion of opaque and glazed surfaces of the inside skin, the operating mode of the double-skin, the type and the position of the shading devices, the quality and the dimension of double-skin openings towards outside and inside the building, the strategy of control of the equipment integrated into the facade, such as the opening of the windows or the use of the shading devices... This study compares consumption of heating and of cooling in a building with or without double-skin when the heating and cooling natural strategies are or are not used, according to the level of insulation and the orientation of the double-skin. (c) 2006 Elsevier B.V. All rights reserved.