Architects need continuous support in their sustainability choices for building design because of the excessive amount and dispersal of information on sustainability. Currently architects utilize BSA tools that provide them general information with a checklist of sustainability measures. However, it is observed that these tools do not fully support a design process; they are mainly developed for assessing a finished design. In that respect, improvements of the existing tools or developing new ones become inevitable to supply architects with more sufficient design support. In this paper, as a part of a diptych, we discuss issues involving the architect’s needs for support in designing a high-performance green building, such as the current support tool, the interconnectedness of performance criteria and the architectural design process. Furthermore, it presents a method for a survey, from which the results are presented in our second paper.