The purpose of this study is to analyze 38 building sites equipped with ondol facilities among 82 buildings excavated from the Hoeam Temple Site, in order to examine the way ondol facilities were constructed and how this process changed throughout the early Joseon Dynasty. Research is carried out with reference to ‘燠室 (uksil)’ ‘ 間 (inkan)’, and ‘溫突 (ondol)’, which appear in the literature records of the late Goryeo and Joseon Dynasties, and to consider the overall value of ondol technology. Ondol is a traditional facility of residential space in Korea. However few studies have been undertaken on what technical changes were passed down to the present day from the early Goryeo Dynasty, when the full floor heating system first appeared. The process of change, from partial floor heating ondol to full floor heating ondol, shows that it is very important to combine the meanings of the developments in the way ondol facilities were made in order to increase the thermal efficiency of the floor heating system. Geographically, Hoeam Temple is located in the central region of the Korean Peninsula and the early Joseon Dynasty (the 15th to 16th century) is the most obvious period of construction. The value of the entire floor area of Hoeam Temple site, based on an architectural archaeological perspective, can be approached though a survey of ondol structures (focuing on age, differences) of the early Joseon Dynasty, on the search for various types of application methods, technological changes (the theory of thermal efficiency development), and on the function of the buildings.