Discover Ancient Korean Underfloor Heating

round the year 37 AD the Koreans developed an underfloor heating system to rival that of the Roman hypocaust Although it arrived later than the Roman style of underfloor heating some experts believe it to be more efficient and accessible to the general populace. The heating system called, ondol which literally means warm stone incorporated underfloor heating into the general practicalities of running a house.

Where the hypocaust used an external furnace to heat one main room of the house which then distributed the heat underfloor to the rest of the house, the ondol actually heated the house from the heat produced by the stove in the kitchen. The heat from the kitchen located at a lower level was channelled through a system of smoke passages using the convection caused by a chimney fitting that created a draft.

The heat travelled through the smoke passages which were lined with thin stone called kudul, translating as fired stone. These stones would retain heat and the floor used insulation in the form of layers of paper on the floor to assist in trapping of heat. Due to this mechanism the heating system could retain heat from one heating from 30 days to 3 months making it the most energy efficient ancient heating system.

In the early 1990s, as Western heating systems began to replace modern forms of ondol the Korean people spoke out claiming that they were losing part of their culture. This lead to the resurgence of ondol and even today hotel rooms can be booked which use this traditional form of underfloor heating as opposed to modern Western heating systems.