It is important to maintain IAQ as well as to save energy in buildings. DCV is proposed to control ventilation rate depending on occupancy in buildings. The CO₂ concentration is widely used as an indicator of the pollutant contaminant in indoor air and often changes with time on account of the number of occupants. Most studies about comparing by ventilation mode use the simulation tool. But this study was conducted through an experiment. In this study, by comparing the adaptability of the four different ventilation mode to existing DCV strategies, critical factors that should be considered in IAQ & Energy for better adaptability to are suggested.