The energy consumed by a building is assumed to be equal to the heat emission by the building. Recent studies show the sensible heat emitted from the building is higher than its energy consumption. The heat released from the buildings can increase the nearby air temperature and the magnitude of urban heat island effect. In general, buildings release heat in three mechanisms by rejecting heat from the air conditioning system, building envelope, and zone exfiltration. This study aims to understand the significant parameters of different design variables on energy consumption and heat emission from a 4-story office building. Sensitivity analysis and parametric framework are introduced to test the hypothesis on 15 U.S. cities to represents all the climate zones. EnergyPlus and JMP are used to simulate the building's performance and sensitivity analyses respectively. The results show that the significant design variable affecting the energy consumption is not the same as the heat emission from the building. For energy consumption, it found the window-to-wall ratio (WWR) is a significant parameter in all climate zones, while the roof reflectivity, SHGC, and heating set point are significant parameters to the heat emission. The importance of this study is to guide designers during the early stage of the design process to understand their decision on both energy consumption and heat emission and make conscious decisions during different stages of the design process.