As part of the Tarbase project, the Tarbase Domestic Model was developed to assess the energy performance of dwellings and options for carbon-saving refurbishments. While subject to the usual limits of steady-state building models, the Tarbase model allows the estimation to be tailored to a specific dwelling, with climate and internal activity accounted for. A wider discussion of steady-state models is given, and the application of the Tarbase model to a real case-study of 100 homes is described. The use of such models can be a valuable, and convenient, way of quantifying the approximate performance of a range of individual dwellings, leading the user to solutions for carbon-saving improvements. However, allowing the model to capture the variation in building specification is of great importance, as is the philosophy of seeing the building as being a product of location, construction and activity/operation. (C) 2011 Elsevier Ltd. All rights reserved.