S-curves to model and visualise the energy performance gap between design and reality – first steps to a practical tool

New and refurbished non-domestic buildings are failing to live up to their anticipated performance. Shortfalls show in excess energy consumption, high carbon dioxide emissions and other failings in quantitative and qualitative performance metrics. This paper describes the component parts of the performance gap using evidence from building performance evaluations. It introduces a way of visualising the consequences of decisions and actions that are known to compromise performance outcomes using a performance curve methodology (the S-curve) which plots performance, and the root causes of underperformance, from project inception to initial operation and beyond. The paper tests the hypothesis with two case studies. The authors conclude that use of S-Curves could visualise performance problems before they become chronic shortcomings, and could be useful for informing activities on Soft Landings (1) projects.