Quo Vadis, energy performance gap?

The topic of the energy performance gap (the difference between predicted and measured energy use) attracts significant attention in the building simulation community. This viewpoint article, which doubles as an editorial on this subject matter, provides an overview of recent trends in the area, whilst also providing a critique on three main issues: (1) the need to specify in some detail what type of performance gap is being addressed, (2) the need for a more holistic approach if we want to address the many root causes of performance gaps and (3) a reminder that we need to be realistic in our ambitions, and that some amount of performance gap is fully natural and unlikely to go away.