Kang Bed-stove
The Kang (Chinese: 炕; pinyin: kàng; Manchu: nahan) is a traditional long (2 meters or more) sleeping platform made of bricks or other forms of fired clay and more recently of concrete in some locations. Its interior cavity, leading to a flue, channels the exhaust from a wood or coal stove. The heat of a cooking fire, usually in an adjacent central room which serves as a kitchen, either a low stove or a stove actually set just below floor level, may be used for maintaining comfort in cool weather. Typically, a kang occupies one-third to one half the area the room, and is used for sleeping at night and for other activities during the day. A kang which covers the entire floor is called a dikang Chinese: 地炕, di meaning "floor".
Like the European ceramic stove, a massive block of masonry is used to retain heat. While it might take several hours of heating to reach the desired surface temperature, a properly designed bed raised to sufficient temperature should remain warm throughout the night without the need to maintain a fire.