This paper focuses on the thermal engineering design and analysis of solid oxide fuel cell (SOFC) units, with emphasis on cell performance and component design. In engineering practice, insulation materials would be deployed as the enclosure of an SOFC stack to reduce the heat loss to the environment. In this work, a computational methodology has been implemented to characterize the thermal engineering performance of a planar SOFC. The present calculation procedure integrates the steady-sate electrochemical reactions of the SOFC with finite-element models for thermo-mechanical analyses of the interconnect through iteration processes, so that a unified temperature distribution with heat loss effect can be obtained. Present results show that the convergent rate of the adopted methodology is quite efficient, and that the temperature patterns are compatible with those reported in the literature. Furthermore, this work has also developed a bulk heat-transfer model for simplified design analysis. The concept of total heat resistance is employed to facilitate the one-dimensional (1D) analyses and to determine the predominant parameters that affect heat-transfer behaviour. Moreover, some accommodation factors have been deduced to correlate the 1D results of lateral heat transfer with those of two-dimensional (2D) finite-element analyses, as this will be beneficial for rapid prototyping processes. (C) 2004 Elsevier B.V. All rights reserved.