There have been many skilled craftsmen in China since ancient times. In the Qin dynasty, some people built the walls of houses into hollow sandwich walls, and set up cylindrical pipes at the entrance below to ignite them, so that heat could enter the walls and the whole house was warm. This kind of firewall has high heating cost. In addition, there is a well-known fire kang in the northeast, which burns charcoal fire directly at the door or communicates with the kitchen stove, making it very convenient to sleep and keep warm. Generally speaking, the heating water temperature is about 65 degrees. However, the situation in different regions will be different, and the heating water temperature will definitely be different, so the specific degree must be determined according to the actual situation in the region. If the residential area is heated by a boiler, the water temperature should not exceed 60 degrees.