Ondol

Traditional Korean rooms have multiple functions. Rooms are not labeled or reserved for a specific purpose; there is no definite bedroom or dining room for example. Rather, tables and mats are brought in as needed. Most people sit and sleep on the floor on thick mats. Underneath the floors are stone or concrete flues. Traditionally hot air was vented through the flues to provide heat. Clay or cement would be placed over the stones to protect the residents from noxious gasses. This type of under floor heating is called "ondol." Nowadays hot water is piped through cement floors covered with linoleum.