▶ Watch the 1-minute version: Cold feet in winter? Korea solved it by heating the floor
How it works
A traditional ondol has three parts:
- Agungi (아궁이), the firebox, usually in the kitchen, where wood is burned for cooking and heat at the same time.
- Gorae (고래), channels under the floor that carry the hot air across the room and heat the flat stones laid on top, called gudeuljang.
- Gulttuk (굴뚝), the chimney at the far end, which pulls the air through and lets the smoke out.
The stones hold the heat for hours after the fire dies, so the floor stays warm through the night. That is why Korean home life happened on the floor: people sat, ate and slept close to where the warmth was.
An old description
The Old Book of Tang, a Chinese history compiled in 945, describes the people of Goguryeo, an ancient Korean kingdom. It says that in winter they built long heated platforms and lit fires beneath them to keep warm. Historians read this as an early form of the same idea.
From one corner to the whole floor
Early ondol heated only part of a room, a raised strip called jjokgudeul, with the rest of the floor left cold. Over time the heated area spread. By the 1600s floor heating was spreading fast across regions and social classes, and the fully heated floor became the Korean standard.
Ondol today
Most Korean homes no longer have a firebox. Hot-water pipes run under the floor instead, heated by a boiler, but the idea is unchanged: the warmth starts at the floor. In 2018 ondol culture was designated a National Intangible Cultural Heritage of Korea. If you stay in a Korean apartment in winter, expect a warm floor and do as locals do: take your shoes off.
FAQ
What does ondol mean?
Ondol (溫突) is the Korean floor-heating system, also called gudeul. Heat from a firebox runs through channels under the floor and warms flat stones.
How old is ondol?
A Chinese history compiled in 945 describes heated platforms with fires beneath them among the people of Goguryeo, an ancient Korean kingdom. Whole-floor heating spread widely in the 1600s.
Do Korean homes still use ondol?
Yes, in modern form. Most homes heat the floor with hot-water pipes instead of a wood fire. Ondol culture became a National Intangible Cultural Heritage in 2018.
Sources
- Encyclopedia of Korean Culture: "Gudeul" (구들, Korean)
- Woori History Net: the development of ondol (Korean)
- Encyclopedia of Korean Culture: "Ondol culture" (온돌문화, Korean)
Written by the Korea in Time team. Each fact above is checked against the sources listed. Found a mistake? Tell us.
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