In this blog post, we’ll examine the nature-friendly architectural methods and heating and cooling principles of hanok—comparing them to Spain’s Park Güell—and explore eco-friendly elements that can be applied to modern architecture.
Not long ago, the popular variety show “Grandpas Over Flowers” featured a segment where the cast visited Park Güell in Barcelona, Spain. In particular, the segment highlighted many of the eco-friendly features Gaudí intentionally incorporated into Park Güell’s various architectural elements. For example, rainwater collected in the plaza is designed to flow through columns and drainage structures into an underground reservoir, and water flows out through a lizard-shaped structure located in the center of the staircase. In this way, Gaudí enabled the collection, storage, and utilization of natural rainwater through architectural design in water-scarce Barcelona. This serves as an example of Gaudí’s environmental consciousness, as he sought to effectively utilize rainwater in the architecture of his time.
At a time when environmental awareness is growing, a building designed over 100 years ago by a genius architect with the environment in mind comes as a refreshing revelation. However, even without traveling all the way to Spain, our ancestors have developed eco-friendly architecture on this land for thousands of years while adapting to the natural environment. This is the hanok. We will explore what eco-friendly architectural elements are hidden within the hanok—our traditional architecture—which, precisely because it is so close to us, we may not be fully aware of.
First, what is eco-friendly architecture? According to the Architectural Institute of Korea, eco-friendly architecture is a form of architecture that emerged to address the problems inherent in conventional construction—which leads to the destruction of ecosystems—as environmental issues have come to the forefront as critical matters directly linked to human survival. For example, the hanok, Japan’s “environmentally symbiotic housing,” and Germany’s “ecological architecture” can all be viewed as architectural styles that prioritize harmony and coexistence between the environment and buildings. In other words, it involves minimizing the environmental impact during both the construction process and the building’s operation.
Hanok, the traditional architecture of South Korea, is replete with such eco-friendly elements. In particular, these houses were built using natural materials readily available in the surrounding area. While palaces and important buildings used neatly squared granite as their foundations, most hanok utilized locally sourced stone for their foundations and corner stones. This stands in stark contrast to the stone used in many modern buildings, which is often obtained by quarrying and processing rock from mountains. Furthermore, rather than insisting on using only straight, perfectly straight pieces of wood, hanok builders took the natural characteristics of curved timber into account and utilized it appropriately. By making the most of natural materials and their inherent properties in this way, they were able to reduce waste and unnecessary processing during the construction process.
Another eco-friendly aspect of hanok lies in the layout of the front and back yards. In most hanok, the front yard is left with an exposed earthen floor rather than being covered with grass, while the rear often features a terraced garden for growing flowers or overlooks a nearby hill. One reason for this spatial arrangement is that it helps keep the interior of the building cool during the summer. The front courtyard features an exposed earthen floor. Because exposed earth interacts with heat differently than areas with dense vegetation, when it is exposed to sunlight, the surrounding air heats up and rises, creating a convection current. As the heated air rises, the resulting pressure difference and airflow allow relatively cooler air from the backyard to flow into the house. In this way, Hanok utilizes natural airflow through the spatial arrangement of the front and back yards, enhancing indoor comfort in the summer without relying solely on mechanical cooling systems.
The length of the Hanok’s eaves is also an eco-friendly architectural element designed for heating and cooling by taking advantage of variations in the sun’s altitude. Hanok is characterized by its long eaves.
Since hanok are wooden structures, the eaves serve to protect the wooden pillars and structural members from rain; however, one of the key reasons for their design is to regulate the amount of sunlight entering the interior. In summer, when the sun’s altitude is high, deep eaves block strong sunlight, preventing it from penetrating deep into the house. Conversely, in winter, when the sun’s altitude is lower, sunlight entering at a shallow angle can penetrate deep into the rooms. By appropriately regulating sunlight using the seasonal variations in the sun’s altitude, hanok reduces indoor temperature rises caused by excessive solar radiation in summer and utilizes sunlight to warm the interior in winter.
Above all, the most representative eco-friendly feature of a hanok is the ondol. The ondol is a floor-heating system—a unique heating method that has evolved over a long period on the Korean Peninsula. In the past, direct heating methods, such as fireplaces, were widely used in various parts of the West. Since fireplaces warm the immediate area around them, they had limitations in distributing heat evenly throughout the entire room. However, the ondol is designed so that the hot heat and smoke generated in the firebox pass through the “gorae” (heat-conducting channels) beneath the ondol tiles, heating them before escaping through the chimney. Consequently, the hot heat is transferred to the ondol tiles, and the heat stored in the stones is then transmitted into the room through the floor, allowing the entire interior to be heated relatively evenly. Furthermore, when the floor is generally warm, convection occurs—with heated air rising and relatively cooler air sinking—which helps warm the entire room. Although traditional ondol systems were designed so that the smoke and heat generated in the hearth fully transfer their heat as they pass through the interior of the ondol before escaping through the chimney, the burning of firewood or other fuels does produce some air pollutants. Therefore, rather than simply describing traditional ondol as a heating method that produces almost no air pollution by today’s standards, it is more appropriate to understand it as a traditional architectural technique that developed an efficient heating principle for storing and transferring heat to the floor using minimal fuel. The principles of ondol continue to be carried forward in modern residential spaces in adapted forms, and today’s underfloor heating systems also inherit the basic concepts of traditional ondol.
Eco-friendly architectural elements are becoming increasingly important in modern architecture. Recently, due to concerns about global warming and climate change, many people have become interested in environmental issues and are actively seeking to incorporate eco-friendly elements into buildings, which serve as primary living spaces. In this context, the various eco-friendly elements found in hanok offer ample potential for application in modern architecture. Methods such as the efficient use of natural materials, eave designs that account for seasonal changes in sunlight, natural ventilation achieved through the layout of courtyards and buildings, and systems like the ondol that effectively store and transfer heat remain highly relevant today. By appropriately combining eco-friendly architectural elements with modern technology, it will be possible to create buildings that reduce the environmental impact while providing a comfortable living environment for occupants.
