Deep energy renovation (DER) of the existing building stock is a key challenge to fulfill the European Union (EU) target of energy efficiency improvement of at least 32.5% by 2030. However, the depth and rate of current energy renovation are far below in achieving this goal. Energy efficiency renovation needs to go beyond the individual building perspective by introducing strategic larger-scale renovation approaches for investment optimization. Yet, due to several hindrances, a slow implementation pace is observed. Therefore, this study identifies the challenges of scaling up retrofitting initiatives from a single-building approach to stock-based analysis. A systematic synthesis method (scoping, systematic review, and meta-analysis of the results) is applied in this paper. Scientific articles collected from SCOPUS and Web of Science together with case study reports assessed through the EU project database have been analyzed within this research. The research discusses the publications available from three main aspects, motivation to initiate large-scale renovation initiatives and drivers & barriers influencing the entire renovation process in the context of the EU environment.  It is observed that the district scale represents a more complex model to be analyzed, calculated, assessed, and managed compared with single buildings. Still, it provides a much better offer regarding renewable energy technology applications, financial viability, smart and innovative design tools. Different technical, social, and economic-related factors could be identified that need to be addressed adequately to initiate the "European Renovation Wave." This review, therefore, advocates the need for a holistic consideration of the entire process, based on which to structure further disciplinary developments. Research gaps are highlighted, and new directions for future research are suggested.