The so-called “Great Heating Divide” of China (GHD) is the term for one of the most far-reaching climate policy decisions made during the 20th century. In the early 1950s, the new Communist rulers determined that for economic reasons, heating would only be allowed in the country’s northern but not its southern half. This political decision, also known as the “Huai River Heating Policy,” has had an enormous impact on the thermal infrastructure, the environment, and everyday life in this vast country to this day. While south of the demarcation line the population is exposed to the cold wet without any official protection from building services and insulation during the winter months, the north must deal with elevated levels of air pollution and associated higher mortality rates due to the widespread heating systems. The main energy source in China for heating is still coal. With its insufficient thermal comfort and high air pollution, the politics of the GHD affects both the interior and exterior of buildings.