- Those dug in loess cliffs, on the side of the valley: a typical example is the city of Yan'an;
- Those dug around an excavation conducted at the surface, serving as interior courtyard, called yaodong-well or sunken courtyard.
The most important and unique characteristic of a Yaodong is that inside it is cool in summer and warm in winter. Generally, the temperature in the room remains between 10ºC to 22ºC and the relative humidity is 30% - 75%. The comfortable temperature and humidity help keep the dwellers fit to some degree. The natural architectural features protect the cave dwellers from being affected by the changes of environment or weather. Besides, its creation does not damage the environment or usurp farmland. Another feature is that you will feel quite quiet inside. In Yan’an in Northern Shaanxi, a family usually has 3 to 5 caves. The middle one is the principal residence, in which the grandparents or parents live. At the bottom right of each cave, people usually leave a small horizontal pass for their pets, such as cats or dogs, to go through. When constructing the gate for the whole yard, there is a traditional taboo that none of the caves should be in line with the gate. Otherwise, bad luck may fall upon this family.
Characteristics:
Plan: Square or rectangular, 6-8 meters long and 3 meter wide
Walls: Cave
Details: None
Height: One floor, 3 meters high
Roof: None, cave with an arc form on the ceiling
Structure: The most newer have in the inside stone or brick as a stand-alone structure
Fire resistant: Unknown
Illumination: Only the front entrance had entrance of light