As household energy consumption has increased, serious environmental problems, such as resource depletion and global warming, are becoming global issues. It is essential to conduct the energy use of residents living in apartments in order to come up with alternative solutions for energy savings. Therefore, this study examined the energy use awareness of apartment residents and their energy use behavior by various types of awareness. To understand their energy use behavior according to the awareness of the subjects, the energy awareness dimension was created with five factors and they were subject to a cluster analysis; then, the subjects were categorized into three groups. Finally, the difference of energy use behavior was examined by groups of energy awareness. G1 represents the group that is indifferent to energy savings and believes that convenience is an important factor. Also, with respect to energy use behavior, this group tends to pursue convenience. G2 is the group that is conscious of energy use costs thereby enduring some inconvenience, and shows savings behavior in daily life and household affairs. Although, G3 is very aware of the significance for the necessity of energy saving, their energy saving behavior is relatively negative. Regarding these different characteristics of each resident group in their energy saving awareness and behaviors, diverse methods and promotion in energy education are required. Furthermore, an effective energy policy should be established based on the understanding of energy consumption.