This paper explores the origins of an air-condition dependency which evolved with 20th century architecture and is related to other developments that affected buildings in the last century, such as the lack of flexibility/adaptability of buildings and their short life span. It then looks at some passive design principles as frequently found in heritage buildings from the pre-air-conditioning era, which are based on heat avoidance and harnessing of natural energies. The paper concludes with a series of recommendations for a holistic pathway to zero-carbon, climate-adaptive buildings.