To improve energy efficiency of existing buildings, various analyses, computational simulations and performance monitoring are conducted throughout the lifecycle of the building, especially during the planning and design phases. One of the most common shortcomings in the current computing infrastructure is that there are bottlenecks in the building processes due to imperfect information exchange, causing frequent and significant delays as, for example, the missing information and data need to be re-produced. This paper discusses the development of a building systems process model being developed as a part of a major energy efficient building initiative that focuses on energy-efficient renovation of medium-sized commercial and multi-family residential buildings. The map aims to depict an integrated building design process flow, especially for analyses, simulations, and information exchanges among the core activities contributing to key decision-making points. In particular, this paper focuses on the development of such a process map through literature review of existing integrated processes and workshops, and defines the requirements and strategies for efficient and seamless information exchange among project participants from different disciplines.