Building is the end product of a design decision making process that starts at the board of an architect. Therefore, in order to make this process responsive to ecological context, which is the theme of this paper, the process must become scientific. The process presented in this paper developes a logical approach based on quantitative assessment leading to qualitative design decisions. A design tool, enabling decision making both at the conceptual and final stages of design, is developed and presented as a decision making matrix. Following the process, contemporary solutions in the form of designs for some projects designed by the author are presented. This approach is by no means inhibiting to architectural creativity and expression.