The purpose of this study was to Apartments planned at the same time in the same area (with the same insulation standard) should have similar energy performance levels, but if you look at the certified energy efficiency grade of apartments, there is a wide variation from grade 2 to 1++. Due to the deviation of the certification acquisition grade that occurs when standardized standards are applied, evaluators and business entities are confused, such as not being able to obtain the target certification grade. Therefore, this study analyzes the design level, energy demand, and primary energy consumption of apartments based on the preliminary certification evaluation of building energy efficiency grades in the same area that can be applied simultaneously to the energy-saving design standards of buildings in September 2018 and July 2019. Through this, it is intended to be used as basic data for obtaining stable certification from the perspective of the building energy efficiency grade certification system and improving the energy performance level of apartment houses.