Le Corbusier's reimagining of society through his unique vision of modern architecture involved creating the ideal environment to house it. In this context, the ocular-centric approach was complemented by an increasing focus on the non-visible dimensions of architecture. Consequently, thermal comfort emerged as a significant topic, as evidenced by proposals such as the Air exact and the Brise-soleil. However, the architect’s experiments with thermal control were controversial throughout his career due to the significant contradictions between his theories, which were based on the sun, physiology, and climate, and the actual experiences and issues faced by inhabitants. While his machinist conception of indoor climates during the 1920s has been extensively analyzed, his transition to an architecture that interacted with inhabitants and climates from the late 1930s, and especially in the 1950s, has been only superficially studied. In this context, we argue that the figure of the French engineer André Missenard was crucial in understanding Le Corbusier’s architecture as the construction of thermal environments. As a thermicien and physics enthusiast, Missenard's influence on Le Corbusier extended beyond technical aspects (such as radiator design, radiant floor heating, and aérateurs) to encompass the entire concept of thermal comfort he envisioned for modern society. Consequently, Missenard’s proposal of the Science of Artificial Climates integrated contributions from physiology, technology, and climatology to create a comprehensive body of knowledge. His collaboration with Le Corbusier during the 1950s transformed the architect’s works into a laboratory for thermal comfort for both of them. This research examines the personal and professional relationship between Le Corbusier and Missenard from 1937 to 1965, a period during which the architect’s works were influenced by the engineer’s approach to thermal comfort and environmental regulation systems. The study explores how their collaborative efforts led to a new understanding of the relationship between architecture, inhabitants, and climate.