The Ecuadorian construction sector lacks thermal comfort standards, causing building’s design to disregard the existing variations between the climatic regions in the country. Indoor comfort levels are generally poor, encouraging the use of unsustainable cooling and heating systems. A building´s envelope plays an important role in the energy and environmental performance of a building. This research investigates whether indoor comfort can be improved by renovating existing facades with a prefabricated facade system that can be mass-customized to respond to different types of climate conditions. A project that uses state-of-the-art technologies, such as CNC milling, to mass-customize construction elements is the WikiHouse. It provides construction solutions with multiple variations, easy assembly processes and the demountability of its components. It guarantees its reusability and reduces the high demand for resources in the construction industry. This research focuses on the design of a facade system that can be mass-customized by combining the construction system of the WikiHouse project and multiple layers with different properties to build one modular and symmetric component with several variations. The replication of the components variants on an existing building´s facades should improve the indoor comfort by responding to the localtions weather. During this research, components variants are developed, by using computational prototyping and simulations. The most suitable components combinations for each facade orientation are selected. This study highlights the influence of climate factors in all its design steps, as well as setting a circular workflow throughout the manufacture, use and return processes. The final outcome of this study is a prefabricated facade system that can be mass-customized to respond to different types of Ecuadorian climate conditions to improve the current indoor comfort levels and allows its demountability and reusability.