This paper provides a comprehensive review of phase change materials (PCMs) integrated into building walls. It discusses various physical considerations, heuristic arguments, and thermophysical properties measurements related to PCMs. The review covers both organic and inorganic PCMs, their integration methods, and experimental and numerical studies. The authors highlight the potential of PCMs to reduce energy demand and improve thermal comfort, but also emphasize the need for further research to fully assess their effectiveness. Key topics include the phase change theory, the integration of PCMs in building envelopes, containment methods, and the measurement of thermal properties. The paper concludes by noting the potential of PCMs to enhance energy efficiency and thermal comfort, but stresses the need for more systematic evaluations under real-world conditions.This paper provides a comprehensive review of phase change materials (PCMs) integrated into building walls. It discusses various physical considerations, heuristic arguments, and thermophysical properties measurements related to PCMs. The review covers both organic and inorganic PCMs, their integration methods, and experimental and numerical studies. The authors highlight the potential of PCMs to reduce energy demand and improve thermal comfort, but also emphasize the need for further research to fully assess their effectiveness. Key topics include the phase change theory, the integration of PCMs in building envelopes, containment methods, and the measurement of thermal properties. The paper concludes by noting the potential of PCMs to enhance energy efficiency and thermal comfort, but stresses the need for more systematic evaluations under real-world conditions.