The third volume of this Special Issue includes ten contributions (eight research and two review papers) from across the world, focused on very interesting research topics. These studies are as follows: Numerical Simulation and Experimental Validation of Thermal Break Strips' Improvement in Facade LSF Walls; Embodied vs. Operational Energy and Carbon in Retail Building Shells: A Case Study in Portugal; Evaluation of Heated Window System to Enhance Indoor Thermal Comfort and Reduce Heating Demands Based on Simulation Analysis in South Korea; Thermal Performance of Lightweight Steel Framed Facade Walls Using Thermal Break Strips and ETICS: A Parametric Study; Application of Machine Learning to Assist a Moisture Durability Tool; Energy Design Synthesis: Algorithmic Generation of Building Shape Configurations; Simplified Guidelines for Retrofitting Scenarios in the European Countries; Thermophysical Parameters and Hygrothermal Simulation of Aerogel-Based Fibre-Enhanced Thermal Insulating Renders Applied on Exterior Walls; Energy Efficiency of Tall Buildings: A Global Snapshot of Innovative Design; and, finally, Advanced Active and Passive Methods in Residential Energy Efficiency.