This paper aimed to review the literature of the past ten years about the energy performance of buildings
during their operational stage. The focus of this review was empirical works that examined the energy
use in real buildings. An overview of the literature survey is presented. A meta-analysis technique al-
lowed the identification of two approaches of study: building-level analysis and stock-level analysis. The
building-level analysis considers the building as the system of study. Otherwise, the stock-level analy-
sis considers a group of buildings as the subject of study while the buildings are elements inside the
system. Notable research topics were addressed involving performance gap, energy audit, retrofit savings
assessment, Zero Energy Buildings (ZEB), benchmarking, regulations and strategies to overcome climate
change. This literature review summarised the level of information of the studies by listing the granular-
ity of the energy performance data according to the purpose of the study. Furthermore, a specific section
was dedicated to assemble the methods and tools adopted. Finally, we proposed conceptual models for
both approaches (building and stock-level) that outlined the main aspects and dynamics identified in this
literature review. Thus, we obtained insights to be investigated in further studies.