In the present scenario each and every industry is facing tough competitive world. It is must for all industries to optimize processes and maximize equipment efficiency so that maximum production and hence maximum profit can be achieved. Also one should find out the field where unnecessary expenditure could be cut down without affecting the process rate. Now-a-days, companies are following some standard step to achieve continuous growth like plant revamping, efficiency enhancement, etc. Each of above mentioned steps has its important role for survival of any industry, and so it can't be avoided. In this project the focus is on efficiency enhancement furnaces at Indian Oil Corporation Limited, (Gujarat Refinery), Vadodara. The objective of the project was to study the past to present improvement in the furnaces, calculate the current furnace efficiencies and to give the suggestions for the further improvements in the inefficiency. To fulfill this objective the work was done on Natural Draft furnace of Catalytic Reforming Unit and Balance Draft furnace of Atmospheric Distillation Unit - 5. The calculations of the efficiencies were done by two methods namely Indirect Method and Calculation by BETZ Energy Engineering Audit Sheet.