An ondol, also called gudeul, in Korean traditional architecture, is underfloor heating which uses direct heat transfer from wood smoke to the underside of a thick masonry floor. In modern usage it refers to any type of underfloor heating, or a hotel or sleeping room in Korean (as opposed to Western) style. Ondol had traditionally been used as a living space for sitting, eating, sleeping and pastimes in most Korean homes before the 1960s. Unlike the western style, Koreans are accustomed to sitting on the floor, sleeping on the floor, and working and eating at low tables instead of raised tables with chairs. With the traditional ondol heating, floor spots closer to the furnace were normally warm enough with warmer spots reserved for elders and honored guests.