ONDOL 온돌
Created Aug 30 2007 by Walus, Mirek
온돌
Korean winters can be chilly, but Koreans of the Choson Dynasty
had used a method similar to the Greek and Roman method of heating for
centuries.
Shivvvverrrring in Korea's cold winter weather, we are invited
into the home of a smiling householder. The welcoming indoor air warms our cold
bodies, though no heater or radiator is in sight. After removing our shoes at
the entrance, we step up onto the floor and find that it is warm. Sitting on the
floor and resting our hands on it, we feel our frozen hands begin to thaw.
In Korea almost every house has this kind of floor heating. It is called
Ondol.
The word 'Ondol' means warm stone. It is loved by foreigners as
well as by Koreans.
Ondol floor heating exhaust stack
Traditionally, the source of heat for the ondol was a
fireplace. This might be located in the kitchen or on the outside wall of the
living room. A kitchen with two or three fireplaces could be surrounded by a
matching number of ondol-heated rooms. In an old Korean kitchen, you might find
one or two big iron cauldrons on the fireplace. Thus, the fire used for cooking
rice or soup was also used to heat the room next to the kitchen!
In general,
the kitchen was built two or three feet lower than the room that was being
heated. The difference in level made it easy for the smoke and hot air to run
under the floor of the elevated room. Smoke running under the floor? Yes, that
is the secret of Ondol.
A traditional Ondol floor heating system conducts the flue
gases of a fire under the floor of a living space. Horizontal flues passageways
for heat and smoke ran beneath the room's floor, connecting the fireplace and
the chimney. Hot air from the fire passed through the flues and heated the stone
and mud floor. This was not as easy as it sounds. Two conflicting requirements
had to be met. For the fuel to burn well, its smoke had to pass quickly through
the flues and go out the chimney unhindered. Flues that were straight and short
were best for that purpose. For the heat from the fire to warm the floor,
however, the hot air and smoke had to stay in the flues as long as possible. To
accomplish this, the flues were made to cover the area under the whole floor,
thus preventing the hot air from going out through the chimney too quickly. When
a happy medium between fast and slow was reached, a room could be kept warm all
night with a fire that lasted only a couple of hours.
Heated floors of the Buddhist temple
It is said that there was once an ondol room—hundreds of
years old—that had incredible thermal efficiency. Because of the design of the
room's flue structure, its floor would remain hot for 45 days with just one
heating! Warmth could supposedly be felt for 100 days. Unfortunately, that room
was destroyed during the Korean War in the early 1950's. In 1982, engineers
restored the structure, and tourists can visit its ondol room. The present
thermal efficiency is not nearly as good as the original. Still, after one
heating, the floor remains warm for ten days in spring and fall, and for three
days in winter, even when the temperature is below 14 degrees Fahrenheit.
Ondol has had a great impact on the Korean life-style. For one
thing, because the floor is much warmer than the indoor air, people naturally
sit on the warm floor rather than on colder chairs. Koreans thus sit, eat,
associate, and sleep on the floor. To keep the floor even warmer, they sometimes
cover it with a thick bed quilt called ibul. When family members come in from
outside, they put their cold legs under the bed quilt to enjoy the comfortable
warmth together—a real bonding experience!
...And this is why you can't see any radiators,
registers, space heaters or extension cords. The form has to be pure, light
and clean.
Photo: Robert Desczyk
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