This research is based on Taiwan’s first zero-carbon green building-Magic School of Green Technology in National Cheng Kung University. Actual energy consumption will be measured to explore benefits of energy-saving. The design origin for this building encompasses 13 green energy-saving techniques. United States Department of Energy dynamic building energy analytical software, eQUEST, is used to execute the strictest energy consumption analytical assessment. It is forecasted to reach an energy-saving efficiency of 65% with energy use intensity (EUI) of 43 kWh/m².yr for the whole building, far below that of 169 kWh/m².yr found in Taiwan low/mid-rise office buildings. This building has begun operation in 2011, through actual readings from Building Energy Management System (BEMS) during January to June, first-half-year accumulated EUI of 19.3 kWh/m².yr against eQUEST analytical assessment of 22.5 kWh/m².yr for the same period. Actual energy consumption analysis for air conditioning, lighting, socket outlet, and power equipment, respectively recorded 41.7%, 11%, 22.3%, and 25% in June. Demonstrating that eQUEST analytical assessed value is very consistent with building’s actual energy consumption readings. The energy consumption standard in the experimental research behind the Magic School of Green Technology stands at world class.