Thermal energy storage is a key strategy to reduce energy demand in buildings, particularly through the integration of phase change materials (PCMs) into building envelopes. Incorporating PCMs into building envelopes enables latent heat storage within a narrow temperature range, enhancing the dynamic thermal response without increasing structural mass. Numerical studies have demonstrated the potential of PCM- façades under different climates and configurations [1]. However, most existing models rely on simplified phase change representations and neglect key effects such as hysteresis, phase change interruption, or time-varying indoor boundary conditions, limiting their applicability under realistic operating scenarios [2]. This work addresses these limitations by developing a finite differences model for the transient heat transfer of adaptive building envelopes incorporating macroencapsulated PCMs, under time-varying boundary conditions. The model solves the one-dimensional heat diffusion equation using the effective heat capacity method, where the phase change is represented by temperature-dependent heat capacity functions. The model accounts for interrupted phase change induced by realistic climate and indoor temperature variations. The model was applied to façade configurations of different mass and thickness, typical of Spanish constructions. Simulations were performed using realistic exterior climate data and variable indoor conditions, allowing the assessment of PCM activation, latent heat utilization, and their impact on the dynamic thermal response. Results show that PCM integration significantly reduces temperature oscillations when the phase change temperature is properly aligned with indoor conditions. The proposed model provides a robust numerical tool for analyzing latent thermal energy storage in building envelopes and contributes to closing the gap between simplified PCM simulations and real operating conditions. Its general formulation makes it suitable for supporting the design and optimization of adaptive envelopes aimed at improving energy utilization and demand matching in future energy-efficient buildings. [1] R. A. Kishore et al. “Parametric and sensitivity analysis of a PCM-integrated wall for optimal thermal load modulation in lightweight buildings”, Appl Therm Eng, 187, 116568, 2021, doi: 10.1016/J.APPLTHERMALENG.2021.116568. [2] I. A. Laasri et al., “Evaluating passive PCM performance in building envelopes for semi-arid climat