It is estimated that in the United States, people spend 90% of their time in buildings. In order to ensure quality of life for communities, we propose a human-centric design approach to building "functionality." "Functionality" is defined as the set of "essential services" to meet occupant needs for safety and well-being. These services include lighting, heating and cooling, ventilation, water supply, and wastewater management. At present, a multidisciplinary top-down approach exists where owners dictate the building operations to architects. Our central thesis is that a bottom-up approach based on occupant safety and well-being should drive the functionality design process. Research on occupant well-being conducted by social scientists should be considered by architects in creating the building functionality layout. One of the results of this research should be a set of the type and level of services required for well-being. Architects and engineers should work together to design physical systems to ensure that the derived acceptable levels of the services not be exceeded for various frequencies of occurrence tied to the weather conditions at the site. In order to make this approach viable, minimal amounts of continuous electric power must be made available such as through building integrated photovoltaic panels. The corresponding onsite power generation and storage needs are therefore a critical aspect of the proposed formulation. It is anticipated that significant interactions during the iterative building design process among the architects and social scientists with the engineering disciplines will change an existing multidisciplinary approach into an interdisciplinary one.