This paper describes a new approach of using simulation directly in construction industry in Czech Republic. Building simulation is used by facade manufacturer in order to present the prediction results to investors, architects and other building specialists to generate discussions and create cooperation. This is necessary for optimal design of highly glazed or intelligent buildings. The paper presents examples of three studies where simulation was used to support design in different stages of the project. The need for simplified simulation tools ready to use during the meeting with investors and architects allowing fast decision making is identified. The paper is concluded with future work which is needed to gain full acceptance by Czech investors and architects.