The growing demand for efficiency in construction has accelerated the adoption of prefabricated modular systems, which streamline manufacturing and assembly, reducing costs and production time. Among the components of modular construction, facades significantly influence thermal performance, structural integrity, and architectural expression. However, their integration requires a careful balance between efficiency, adaptability, and regulatory compliance. This research investigates facade solutions for modular construction, focusing on parameterization and thermal optimization. A parametric design approach was used to explore variations in wall composition that improve thermal performance, as measured by U-value, while meeting formal design rules. To validate the methodology, the opaque facade of a one-bedroom 3D module designed for student housing was modelled. The study applied insulation parameterization based on the portuguese thermal regulation, along with contextual variables such as climate zone and material properties. The results highlight the potential of parametric design and modular construction to enhance thermal comfort, increase efficiency, and support the development of integrated, regulation-compliant facade solutions for future modular buildings.