This study sought to examine ways of reducing energy demands in the residential building sector by measuring energy usage and associated factors in Bundang District. This District represents the first phase of new towns in the Seoul metropolitan region to implement current polices directed at climate change. The majority of residential buildings in this district were constructed between 1991 and 1995, prior to the announcement of the integrated building design criteria directed at saving energy and intensifying thermal transmittance. The proportion of small households was increased by almost 40% from 2000 to 2010. Further, a number of weather records have been broken in the last two decades. These changes are strongly related to energy consumption patterns and trends; however, current polices, acts, and regulations do not sufficiently address these issues. This study suggests building energy-saving strategies that: (i) improve energy performance in existing buildings; (ii) strengthen building design criteria to address climate change issues, especially in relation to design and construction; and (iii) offer a framework to revitalize Korea’s energy-savings policies.