This paper describes computer software developed specifically for the analysis of airflow in the design of automotive A/C systems and its applications for improving performance of such systems. Traditionally, design of an A/C system involves building and testing of prototypes. The objective of this project was to develop predictive capabilities where an engineer can assemble a system in the computer to obtain desired air-flow performance. The computer program is integrated and customized for designing A/C systems. It has two parts: the first part, performance analysis, requires the air circuit modeling of an A/C system where each component is modeled in terms of appropriate design parameters. A system analysis is performed to predict the interaction of the components and the total system performance. The second part of the computer program performs component analysis. The geometry of each of the part are first modeled on a CAD system and then imported to form a simpler engineers model. This model is used by the engineer as a tool for building a finite element grid and then to perform the finite element flow analysis. Obtained numerical results predict the details of the flow field and the critical regions for generating pressure losses. An engineer can modify the geometry of the part and rerun the program towards finding a geometry that can provide improved flow performance.