The Chapter will include an introduction to the context of the performance of buildings in use – changing energy and environmental targets and the development of new designs, materials, and technologies to meet these targets. The questions that emerges is, are these successful? Are the targets being met and if not why not? And are there related effects on performance – do improvements in one area lead to deficiencies in others?

In effect the construction industry is conducting a series of experiments and it is important that we go back and check the results, and more importantly, learn from these. However, this type of activity is not standard practice in the construction industry. This chapter describes a series of projects that have developed and undertaken building performance evaluation (BPE). These include the development of tools, examples of BPE projects, and case studies of the type of insights that can be gained from such projects; and will conclude with a summary how these can inform both clients and designers.