The purpose of this paper is to pinpoint some of the areas of the analysis of energy consumptionin existing buildings where inspection and field performance testing by competentengineers is crucial to the effective outcome of the energy audit. For the purpose of this study,a college campus has been analyzed as discussed in this paper and an energy audit has been made.Results have been presented both based on extensive field measurements of HVAC systems performanceand also as if this effort were not undertaken and design data only were used to establisha few of the important operating conditions. It is intended that the magnitude of error causedby disregarding the necessity of field performance measurement will become apparent through thesestudies.