[1] Korean architecture considers the positioning of the house in relation to its surroundings, with thought given to the land and seasons.
This principle is called baesanimsu (배산임수; 背山臨水), meaning that the ideal house is built with a mountain in the back and a river in the front.
In the cold northern regions of Korea, hanok are built in a square with a courtyard in the middle in order to retain heat better.
Iron Age hanok had Ondol, and also used giwa (기와), a kind of roofing tile which was made with fired clay.
However the value of hanok has been discussed in the early twentieth century, with many comparing them favourably to the more common but less eco-friendly apartments found across South Korea.
After the 1970s, with urban development, many apartments and terraced houses were built in South Korea, and many hanok were demolished everywhere.
[4] The environment-friendly aspects of traditional Korean houses range from the structure's inner layout to the building materials which were used.
Since Korea has hot summers and cold winters, the Ondol (Gudeul), a floor-based heating system,[5] and the Daecheong, a cool wooden-floor style hall, were devised long ago to help Koreans survive the frigid winters and to block sunlight during summer.
[citation needed] Hanok have their own tiled roofs (기와, giwa), wooden beams and stone-block construction.
Due to the warmer weather in the southern region, Koreans built hanok with the rooms aligned in a straight line.
The houses of provincial commoners (as well as some impoverished yangban), with choga (a roof plaited by rice straw), were built in a more strictly functional manner.