## 1 Introduction
The study focuses on the Italian territory and the prevalent building typology, providing insights into the economic feasibility of energy requalification interventions under the Superbonus scheme. In [5], the authors introduced a novel energy storage system that comprises a supercapacitor bank and a bidirectional six-phase interleaved DC/DC converter. Through simulation tests, they investigated the energy savings achieved by this proposed system. The model of the system considered all the relevant physical constraints, and its accuracy was validated using field measurements. By utilizing the validated simulation model and considering the physical constraints, reliable results were successfully obtained. The proposed energy storage system's performance was evaluated under various conditions, and the simulation model was further tested, using elevator traffic data obtained from the measurements of the existing elevator system. The simulation results demonstrate the effectiveness of the proposed energy storage system and highlight its potential for significant energy savings. In [6], the authors presented a novel design for a transfer learning approach that addresses dissimilarity issues by incorporating a specific data selection methodology. This procedure utilizes neural network models and analyzes prediction uncertainties associated with the target application samples. To validate the proposed methodology, it is applied to a semi-supervised transfer learning case study, involving two publicly available air-handling unit datasets that include various fault scenarios. The results highlighted the potential of the proposed domain dissimilarity analysis, whereby it achieved a classification accuracy of 92% within a transfer learning framework. This represents a significant improvement of 37%, compared to conventional approaches. Finally, in [7], the objective of the study was to examine the impact of human thermal plume on the measurement performance of thermohygrometers. To achieve this, a simple and replicable \"Do-It-Yourself\" device was utilized. The device consisted of 10 iButtons attached to 3D-printed brackets, enabling their placement at various distances from the body. The device was affixed to the user's belt while in a seated position. Two scenarios were considered: a summer scenario with an air temperature of 28 \({}^{\circ}\)C and a clothing thermal resistance of 0.5 clo; and an autumnal scenario with an air temperature of 21 \({}^{\circ}\)C and a clothing thermal resistance of 1.0 clo. The findings demonstrated that the proximity of the measurement station to the body significantly influences the accuracy of the measurements. This factor should be considered when developing new wearable devices for assessing thermal comfort. As a recommendation, it is suggested that the development of a new wearable device that is attached or embedded onto a belt should include at least two thermohygrometers. The first should be positioned as close to the body as possible, while the second should be placed at least 8 cm away. This approach enables the assessment of potential discrepancies between the standard thermal comfort evaluation and the user's personal perception, as well as the exploration of the potential role of spatial proximity in thermal comfort assessment. The seven papers published in this Special Issue of _Applied Sciences_ collectively reinforces the crucial need to conduct further studies in relation to this topic, in order to enhance our comprehension of all the elements that constitute an \"efficient\" building within a multi-domain context. All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication. All authors have read and agreed to the published version of the manuscript. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as potential conflicts of interest.