The change of heating load for domestic residential buildings was analyzed in this study. For this purpose, the change of heat transmission coefficient was studied and the heating load was calculated. Although the heating load in domestic residential buildings has been reduced, these circumstances have not been applied to floor heating panel design. In this study, the reasonable design of a heating panel based on an analysis of relation between heat output and design factors of a heating panel was suggested. According to the results, considering the actual heating load, a wider pipe pitch, a smaller pipe size, and a lower water temperature than those at present could be applied to the heating panels of residential buildings.