Recently, the political and social interest in energy-efficient residential buildings in South Korea, as well as the required technical measures for such practice has grown rapidly. However, experience in the field of energy-efficient buildings in Germany has indicated that not all proven measures for energy efficiency have achieved the expected energy savings in practice. "Incorrect" user behaviour has been repeatedly mentioned as a cause of such failure. Sometimes certain measures caused a thermally uncomfortable indoor environment or even mould growth, which results in user complaints. Therefore, a holistic approach taking the indoor climate, energy efficiency and user behaviour into consideration becomes more and more important. The objective of this thesis is to analyse the current situation of representative South Korean high-rise residential buildings and to offer recommendations based on the holistic, multi-faceted approach considering thermal comfort, energy efficiency and user behaviour. For this purpose, measurements and questionnaire are conducted. This study shows that "incorrect" user behaviour can be physically explained and could be avoided. The user and the environment should be considered carefully prior to the implementation of a specific measure.