A lack of standards that define the energy auditing process and the energy modeling methods for the retrofit building sector has resulted in variable outcomes. One cause of the variability is the limited time industry members have to devote to energy model development coupled with the lack of understanding of which input parameters are the most effective in terms of energy use projections. For the research, a case study is presented regarding a retrofitted building, which was not performing as the energy model created during the retrofit design had projected, and possible reasons for the discrepency are identified. LEED documentation, the retrofit design drawings, and the energy model report were used to recreate an eQuest model that aligned with the original eQuest model used for the retrofit design process. A sensitivity analysis was performed to determine the effect-specific energy modeling input parameters (identified through the case study) had on the energy analysis outputs. The intent of the research was to confirm that energy modeling input parameters have varying effects on energy use projections. With a clearer understanding of the varying effects input parameters have on energy use projections, industry members can begin to sense where they should allocate time when developing an energy model.