Dayasari RC is an old low-rise multi residential building which was established in the year 1966 and is located in the University of Malaya (UM) campus in the capital city of Kuala Lumpur. This building was designed with the internal courtyard that allows numerous implementations of bioclimatic design strategies, especially in regard of natural ventilation. Eight unoccupied student rooms were selected to represent ten different scenarios, where two from eight selected rooms had been chosen to represent two different scenarios. The scenarios are concerned with the level of radiation and penetration of sunlight that influence the values of temperature and relative humidity. Different natural ventilation approaches were introduced simultaneously in all selected rooms for four weeks. Initially, the effectiveness of different ventilation approaches is obviously influenced by the position/floor level rather than the orientation of the selected rooms. The night ventilation is the most effective approach due to the lower mean temperature and higher relative humidity values. The recorded mean temperature values were below than 30 'C with the relative humidity values exceeding 70%. Other ventilation approaches namely; daytime, full-day, and no ventilation, were more than 30 degrees C and had exceeded 32 degrees C at certain rooms. The ranking of the effectiveness of the ventilation approaches was in the following order; night ventilation>daytime ventilation>full-day ventilation>no ventilation. (C) 2014 Elsevier BM. All rights reserved.