Part 3/14:
Ancient civilizations devised more inventive systems. The Greeks and Romans, for example, developed foundational central heating methods for large buildings. The Romans pioneered hypocaust systems, where heated air was directed beneath floors and into wall cavities, warming villas and baths—an extraordinary feat for the era. Similarly, Korea’s ondol floors used heated stone underfloor systems, demonstrating early understanding of radiant heat. However, these systems were complex and typically limited to the wealthy elite.