Energy conservation and waste heat utilization are important global issues of our time. Attock Oil Refinery Limited (ARL) is a pioneer in crude oil refining in Pakistan. Following thorough surveys and analyses, the Heavy Crude Unit (HCU) was selected for energy savings and waste heat utilization. A detailed study of the facility led to the identification of potential zones for energy savings and waste heat recovery. Energy savings were achieved in the preheating line, which exchanges heat between high-temperature products and low-temperature crude oil. By increasing the heat exchange, both the amount of fuel burned in the heater to warm the crude oil and the coolant used to cool the products could be reduced. Waste heat recovery occurred from the flue gases of the combined chimney from two heaters, which were discharged into the atmosphere at a temperature well above the setpoint. The recovered heat could be used to warm the intake air for combustion in the heating device, which operated at ambient temperature, thus conserving fuel and benefiting the environment, addressing both economic and global warming issues.