First coined by American indoor climate engineers in the 1920s, the concept of the comfort zone has since gained traction beyond buildings and houses, in domains as varied as psychology, business management and education. This paper provides a genealogy of the term, tracing its roots in classical political economic theory. It situates comfort zones in a world ecology, from the domestic sphere to the farm, from the office to the factory floor. Today, comfort zones are shaping both the climate crisis and responses to it. The construction of climatically regulated spaces is central to capitalism’s vital operations, exclusions and sacrifices; oriented to the lifecycles of machinery, microchips and microorganisms as much as humans; and shadowed by a politics of discomfort.