This paper describes the application of a building simulation program to construct a decision-support tool for use by policy makers addressing the needs of the Scottish domestic sector. It is argued that the generic nature of the tool renders it suitable to support the cumulative roll-out of upgrade measures in the long term, both within and outwith the UK. The tool is then used to appraise the impact of the upgrade measures that might be applied to the Scottish housing stock. (C) 2004 Elsevier B.V. All rights reserved.