A new model for predicting the thermal and electrical performance of solid- oxide fuel cell (SOFC) cogeneration devices for residential buildings has been developed. This is a system-level model that considers the thermodynamic performance of all components that consume energy and produce the SOFC- cogeneration device’s thermal and electrical output. The model relies heavily upon empirical information that can be acquired from the testing of coherent systems or components and is designed for operation at a time resolution that is in the order of minutes. Hence it is appropriate for use in wholebuilding simulation programs where it can be applied to assess the energy and greenhouse gas emissions benefits of this nascent technology.