For petroleum and petrochemical industries, energy management is an important element to controlling total operating costs. Over the past decades, there appears to be an urgent need to retrofit the existing heat exchanger networks (HENs) of the plant to reduce the current utility consumption.A simple pinch design approach is proposed here to accomplish above-and-below pinch HEN design by stage-model mathematical programming using commercial software; GAMS.The energy and capital costs of a heat exchanger network are both dependent on the pinch temperature or minimum temperature approach (ΔTmin) which is set as a target design parameter prior to designing HEN. In this work, a retrofit potential program is developed using VBA (Visual Basic for Applications) to find the optimum ΔTmin at the targeting step. Moreover, the program can automatically generate composite curves and grand composite curve of the process. Finally, the stage-model mathematical programming helps design the improved HEN with optimal profit or net present value (NPV).