This paper aims to evaluate the resiliency and environmentally friendly nature of historic preservation and sustainable development by surveying the office building stock within the city of Chicago. Through an evaluation of the operational energy consumption post-development, this paper will address the relation of each building practice and their overall efficiency. Considering each building’s ENERGY STAR rating as an indicator for sustainability and efficiency, this paper will model several variables to illustrate whether a relationship exists between the age of a structure and its building design, with respect to its energy efficiency. However, it must be noted that the operational energy is not the only aspect that contributes to a building’s resilience; the materials and construction process that make up each structure’s embodied energy also hold significance. The energy needed to demolish a building in order to replace it with a new one can also contribute to the energy life cycle of a structure. One must take a holistic approach when considering the efficiency of a building.