Our sleeping experience on the farm in Hongcheon was a unique one in that we were in a very traditional house. Many Koreans sleep on the floor, and this night provided no exception, but the truly unique thing was in how the heating is provided.
I’ve seen a few homes in the U.S. which are heated by radiant heating, coming from the floor by way of embedded pipes carrying hot water through them. Although rather new to American homes, this idea was apparently first developed around 3,000 BCE as part of the traditional Korean home where the sleeping area is heated by a unique under-floor heating system powered by the wood-burning stove in the adjacent room.
The system, known as “ondol” is built around the fire which is often used for cooking dinner. As the fire burns, the flue carries all of the smoke (and heat) outside. In a typical home, this heat just escapes straight up through a chimney, but in the case of the traditional Korean home, however, the flue runs underneath the house and out the other side before it gets to the chimney. During the process, the floor is heated up, so much so that one fire in the early evening was enough to keep the floor and room toasty warm all night and through the next morning!