In this paper, the thermal efficiency of the heat exchanger network of an existing crude distillation unit (CDU) was evaluated. The main goal is to determine how much energy savings can be achieved by network retrofitting. Energy losses are inevitable especially in process where equipment and heat integration network design are outdated. Pinch analysis method can help in minimizing the energy losses by retrofitting the heat exchanger grid and it is proven to be successful in many applications to predict more efficient heat exchanger networks. A base scenario case study was suggested to determine the maximum possible energy savings that can be achieved. In this scenario, the energy analyzer model in Aspen HYSYS was used to determine the optimum energy network that can accomplish maximum energy recovery with minimum capital cost. Another alternative was also evaluated using pinch analyzer tools in Aspen HYSYS. In this scenario, the existing heat exchanger network was optimized to determine how much energy can be recovered. All analysis conducted were based on the existing cooling and heating utilities in the plant. The results obtained indicate that around 67.5 MW of maximum cooling and heating utility can possibly be recovered compared to the existing utility load of 148.6 MW. This represents around 45% reduction in heat utility requirements. There is also an indication of substantial positive environmental impact in terms of how much reduction in the CO 2 emissions that can be achieved reaches up to 1079 kg CO 2 /h for a practical and feasible option, and up to 7840 kg CO 2 /h for grass rooting retrofitting scenario.