Recently, the window area ratio of buildings has increased but the thermal insulation performance of windows is lower than the wall. Therefore, many studies have been carried out to reduce this heat loss. The Republic of Korea policies and guidelines for windows do not consider the optical and design elements of windows because it is more important to the insulation performance of windows. This paper proposes the supplement point of the Korea's policies and guidelines regarding windows through a comparison of Korea's policies and guidelines for windows, checks the variation of the energy consumption of buildings through the variation of the window elements, and proposes an energy analysis indicator for the Republic of Korea's situation. This study confirmed that the variation of the window elements affect to energy consumption by previous studies to consider in window design according to the policies and guidelines. The window elements were divided into performance elements of the windows and architectural/equipment plan element. By analyzing the energy consumption by changing the element, this study confirmed the variation of energy consumption by using the COMFEN4.0 simulation tool. This paper proposes an actual energy analysis indicator in the Republic of Korea. (C) 2014 Elsevier B.V. All rights reserved.