Review of the building energy performance gap from simulation and building lifecycle perspectives: Magnitude, causes and solutions

The building energy performance gap (EPG) seriously restricts the improvement of building energy efficiency. Currently, although many studies on EPG, it is not yet fully understood and addressed. To fill this gap, this paper conducted an extensive review of EPG research. Firstly, the magnitude of EPG was summarized from many case studies, and the results showed that it varied greatly among building types, with gap ratios ranging from 0.5 to 4 for educational/research buildings, concentrated between 0.5 and 2.5 for residential buildings, and between 0 and 1 for office building. Then, fifteen direct causes and seven in-depth drivers of EPG were analyzed from simulation and lifecycle perspectives, and the linkages between them were established. Furthermore, solutions for EPG were summarized, including some state-of-the-art technical and “soft” measures, and their correspondence with the underlying causes. Finally, eight future research recommendations were proposed based on the limitations of existing strategies.