Radiant Heat BESI's "Radiant Roll" EPDM tubing system disappearing under a pour for a new radiant, hydronic slab. by Paul Hanke Praised for its ability to provide draft-free, even heating that is economical and virtually noiseless, radiant heating has been used for centuries. The Romans used a hypocaust to channel warm air under the floors of their villas. A similar system, the ondol, was used in Korea to channel flue gases underfloor, thereby providing warmth on the way to the chimney. More recently, large masonry stoves that radiated heat into living spaces for hours or days after fuel ceased burning were used in several eastern European countries. In the U.S., Frank Lloyd Wright championed radiant