As buildings evolve to meet the challenges of energy efficiency and indoor comfort, phase change materials (PCM) emerge as a promising solution due to their ability to store and release latent heat. This paper explores the transformative impact of incorporating PCM on the hygrothermal dynamics of multi-zone constructions. The study focuses on analyzing heat transfer, particularly through thermal conduction, in a wall containing PCM. A novel approach was proposed, wherein the studied system (sensitive balance) interacts directly with a latent balance to realistically define the behavior of specific humidity and mass flow rates. In addition, a numerical model implemented in MATLAB software has been developed to investigate the effect of integrating PCM on the hygrothermal balances inside the building. The obtained results indicate a consistent response in internal temperatures, specific humidity, and mass flow rates, with temperature differences ranging from 5°C to 13°C and a maximum phase shift of 13 h. In addition, the findings provided valuable insights into optimizing the design and performance of multi-zone constructions, offering a sustainable pathway for enhancing building resilience and occupant well-being.