This study proposes an Architectural Expert System (AES) to act as a design partner for architectural designers. Architectural designers are faced with a very complex task of searching a solution space, which is a labyrinth of several domains ranging from social to cultural, and from aesthetic to scientific. With the number of domains come a number of experts of that domain. After progressing through tedious analytical procedures involving the physical principles in architecture, and applying the knowledge of experience, the experts are able to convert the raw data into useful design guidelines. Research in the field of artificial intelligence has developed techniques which can capture such expertise in a computer program, which then emulates the expert. This technology is know as Expert System (ES). This study has used this technology to develop a system to aid architectural design. An AES model is derived from literature review. As the nature of a system based on this model is complex and would require custom built software, an alternative is developed based on the derived model. Based on this alternative, a prototype is developed for energy audit and energy conservation by capturing the expertise of an energy conscious design expert. This prototype module is one component of the sub-system of AES and provides an example for further modules. Various areas such as design, architecture, artificial intelligence and expert systems technology, and energy conscious design and energy conservation converge, and become parts of this study. / Master of Science