Korean Traditional Ondol Heating System Explained

South Korea's Arirang news teaches about Korea's traditional underfloor heating system, which originated in the north and spread to all of Korea in the Joseon period, and is still used today in both traditional and modernized forms. The documentaries visit rural areas to show the traditional smoke-based ondol system in use, and also show the uses of modernized water-based ondol system.

"Embodiment of Green Energy, Ondol under the Global Spotlight"

Ondol is a heating system that uses a humble furnace to warm the entire house. Considered one of the 3 great inventions of Korea, along with Hangeul and movable metal type, the ondol system has grabbed the world's attention.

[Visitor to ondol house] "The fire is very pretty when lit up, and the sweet potatoes that are baked in the live embers taste so good."

For Korean people, stones are very useful tools for overcoming the freezing winter. Heated pebbles can serve as pocket heaters, while wide stone slabs are sometimes used as cooking utensils. In this village in Gapyeong, Gyeonggi-do Province, the neighbors have gathered around a large stone slab over a fire to warm up. There is something special about this stone slab that is acting like a grill -- it's none other than a geudeljang [stone for making ondol floor]. They are cooking meat on a heated geudeljang.

Ondol also enabled traditional greenhouses, using the underfloor heating of the smoke to control temperature combined with steam from cooking pots to control humidity (@25:17)

Joseon's greenhouse came 170 years ahead of Europe's first heated greenhouse ... The greenhouse was built to cultivate various crops and vegetables even during the winter. Its special feature is the ondol system ... The technology can easily pass as something used in today's world ... Thanks to this greenhouse, people were able to eat fresh vegetables in the middle of winter.

[Resident of traditional house] "Living in an ondol room is good for your health. Your heart becomes warm and opens up more easily. All your troubles just melt away." [Other interviewees] "It's very warm. I remember how, as a child, I used to sit in an ondol room, where the air was cool while the floor was warm." "This ambiance of hanok [traditional house] is something that you can't experience in even the most luxurious hotels."

@38:22 you can see a train which has ondol floor in its cabins, people sit on the train floor to feel the ondol heating

[Discussing modernized ondol which uses heated water instead of smoke] What will happen if the ondol heating system, considered clean, green energy, meets solar power? The result could be a perfect zero energy building.

"100 Icons of Korean History, ep. 35: Ondol"

The Korean traditional floor heating system "ondol" dates back to the Gogureo era. It originated in cold northern regions and spread to all southern areas during the Joseon period. It still remains the indispensable part of Koreans' everyday lives. That's why many idioms in Korean are about the heated floor "ondol" or "gudeuljang."

[Visiting Jeong-eup, North Jeolla Province] People here still use firewood to heat their houses and cook. Mothers cook for their families to the alluring scent of burning wood in the kitchen during cold winters and warm the rooms. When the family members come home, they snuggle under the covers and chat on the warm floor.

Ondol is nostalgia. Smoke rising from a house's chimney evokes nostalgia in Koreans, who cherish even the familiar scent. Ondol brings people together and helps them forget about the cold.

[Resident of Gunsan interviewed] "It's a good experience for foreigners as well. I'm proud to say Korean ondol is the best."