What were some of the earliest forms of heating and ventilation used by ancient civilizations?

The ancient Greeks, Romans, Egyptians, Chinese, and Indians all developed innovative ways to heat and ventilate their homes and public spaces. For example, the Egyptians used manual fans, while the Indians employed rope fans. The Romans, on the other hand, developed a central heating system known as hypocaust, which featured a furnace in the basement and flues to distribute heat throughout the building. This system even included radiators for heating rooms and steam for bathing. These early innovations laid the groundwork for modern HVAC systems.