Polymer-Based Phase Change Materials for Smart Glazing: Enhancing Thermal Regulation and Energy Efficiency in Buildings

Phase change materials (PCMs) for thermal energy storage have attracted significant attention due to growing demand for more environmentally friendly, low-energy building materials. As far as novel technologies are concerned, PCMs based on polymers which are incorporated direct in window panes represent an appealing possibility to achieve a passive control of the indoor temperature by storing and releasing heat. This article reviews the fundamentals, synthesis methods, performance parameters and limitations for PCM SMART glazing systems. It is regarded with organic, inorganic as well as eutectic PC and latent heat storage properties especially the polymer matrices (PMMA/PUR/PVB) which were used for encapsulation, stabilization and optical clarifying process. Recent studies (2020–2025) show that PCM in glazing can reduce annual heating and cooling demand by 15–35%, achieve the latent heat of 60 and 90 kJ•kg⁻¹, while it maintains Tavis >65%. Advanced Strategies Micro-encapsulation, Nanofiller Loading (Graphene, BNNS), and Polymer–Nanocomposite Hybridization Advanced strategies for enhancement of thermal conductivity, durability, and transparence have been developed. However, there are also problems of how to suppress the leakage, RFHC and optical–thermal conflict for PCM16-glazing process. Challenging developments are bio-based PCMs, solid–solid transitions and smart façades in the Internet of Things (IoT) involving real-time thermal response. Life-cycle and techno-economic analyses reveal favorable energy payback times (2–5 years) and CO 2 savings potential. The review in its entirety demonstrates the potential of polymer PCM glazing as a promising multifunctional solution for net-zero and adaptative building envelopes from material science, architecture design and environmental sustainability perspectives.