This paper combines two research publications working toward the development of an integrated framework for commercial sustainable building design. Current methodologies utilize a traditional architectural top-down approach to sustainable building design practices that consumes financial and temporal resources early in the design process. By identifying the array mechanical subsystems required to meet modern building standards such as net-zero energy and water, and recognizing the importance of these interactions, designers can mitigate this resource consumption. The first paper presents an anthropological case study of the schematic design process of the Oregon Sustainability Center, a net-zero building slated for construction in Portland, Oregon. This research outlines the complexity of mechanical subsystems required to achieve net-zero standards and how project stakeholders affect the design process. The second paper further explores this concept by analyzing building subsystems in the context of a traditional complex system (airplane, automobile, etc.), and uses optimization techniques to understand significant system interactions. A computer model is created that optimizes lighting availability for a commercial workspace incorporating cost, building standards, and user environment. By considering post construction building usage, each subsystem can be designed for maximum user productivity, reducing costs associated with sustainable design practices.