In the construction sector, the integration of active elements functioning both as building envelope material and on-site electricity generator is identified as a key measure to achieve the 2050 targets and carbon neutrality (Aguacil Moreno, 2019; Aguacil Moreno, Lufkin, & Rey, 2019). Despite an increasing confluence of the photovoltaic (PV) industry and the building glass manufacturers, which offers high design freedom in relation to size, colour and texture, architects and engineers continue to address the issue in a traditional way, by limiting themselves to the application of "standard" catalogue products that particularly constrain their designs (Bonomo, Frontini, De Berardinis, & Donsante, 2017; Zanetti et al., 2017). This way of working, which makes it difficult to integrate PV systems into the building envelope and, therefore, into the overall building design, often leads to a method of sizing that largely makes abstraction of the building’s electricity needs. This article presents the application – in an ongoing design process – of an innovative active surfaces selection method adapted to the design phases using 3D-modeling and hourly-step simulations (Aguacil Moreno et al., 2019) using Rhino (Robert McNeel & Associates, 2019) and Grasshopper (Davidson, 2018). Through an integrated-design approach, the proposed workflow allows to quickly obtain visual and quantitative results on the building envelope, and supports a design decision-making process that proposes an alternative approach to usual practice.