newsweek.ro/international/secretul-de-2000-de-ani-

For over 2,000 years, Koreans have used the ondol heating system, which warms homes from the floor up, effectively combating extreme cold. This traditional method, integral to hanok houses, channels heat from a cooking fire through underground flues, heating the floor and maintaining warmth long after the fire goes out. Modern adaptations utilize water pipes or electric systems, but the principle remains the same: a uniformly heated floor. While efficient, the effectiveness of ondol depends on construction quality and insulation. Traditional ondol requires professional installation due to safety risks, unlike modern systems that can be DIY. Overall, ondol exemplifies a sustainable heating solution that has endured through centuries.