Although interest in and the importance of green building certification have increased, it is difficult to determine how much less energy the buildings actually consume after obtaining sustainability related certification, such as LEED in the USA, and G-SEED in Korea. Focusing on building energy evaluation, we compared and analyzed the energy evaluation items of LEED and G-SEED. In addition, from the Korean public data portal site, this study investigated the annual site energy consumption (electricity and gas) per floor area of non-residential buildings that obtained G-SEED certification in Korea. The energy consumption of non-certified general buildings was compared with the energy consumption of certified buildings. As a result of examining 84 samples of this study, non-residential buildings with G-SEED certification showed energy use intensity that was at least (35.5 to 48.9)% lower than that of uncertified buildings.