Sensitivity of façade performance on early-stage design variables

Early-stage façade design is a complex and multi-objective process. There are two principal barriers in the process of identifying an optimal façade solution. Firstly, the number of design variables and their uncertainty are relatively large, making design decisions difficult. Secondly, each design variable is likely to affect several performance indicators simultaneously, which makes it difficult to quantify the impacts of the design variables. In this paper, we perform sensitivity analyses on two generic building scenarios (a cellular office room and an open-plan office floor) in three geographic locations (London, Helsinki, and Rome). A series of façade sensitivity coefficient charts for early-stage façade design are produced for these locations thereby providing quantitative relationships between a comprehensive list of design variables and façade performance indicators. The sensitivity coefficient charts provide a guide for allocating the limited design time and construction budget to the design variables that will generate the largest impact on facade performance.