The main objective of this study is to assess the baseline of energy performance of detached houses for low-income households. According to the Home Energy Efficiency Assistance Program in South Korea, the analysis should be performed on a “reference house” in order to select the most effective refurbishment measures. The reference building was developed by using a recent dataset extracted in 2013. The heating energy performance of the reference house and the potential energy savings were assessed using the monthly calculation method of ISO 13790. Established building model and Korean building type were used as a means to evaluate energy demands and to assess potential energy savings. The comparison shows a considerable difference of the annual heating energy demand. The heating energy consumption target of the building was set at 173.15 kWh/ m²∙yr as compared to the figure of 252.17 kWh/ m²∙yr for the building typology. Furthermore, the outcome of this study provides the basis for further investigations aimed at assessing cost optimal and energy effective approaches to the retrofitting of detached houses for low-income households.