Abstract The study focusses on parametric optimization of condenser used in Organic Rankine Cycle (ORC) to recover waste heat from industrial exhaust. The thermal properties of R245fa are obtained from REFROP-9.0 and the calculation as per the mathematical model has been carried out using MATLAB 2019. Effect on variables is studied on the total heat transfer surface area and cost with channel distance, width of channel, length of the plate, mass flow rate and velocity of refrigerant. Furthermore, effect of mass velocity of refrigerant is studied and the trade-off between the two objective function is presented. The trends observed in the results are presented where there is a trade-off between cost and the total area of heat exchanger. The mass flow rate and mass velocity have significant effects on optimizing design of condenser because a small change results in huge changes in the area of heat exchanger and cost, whereas channel distance, channel width, velocity and mass velocity of R245fa have less effect. The mass flow rate of R245fa has a promising effect in optimizing design of condenser for a minimum value of 3.5 kg/s, the change in the value of the area is 90 m2 and 12,500 euros in cost. Similarly, when the parametric factor of mass velocity is around 120 kg/m2 s, minimal cost is attained and the area observed is around 86 m2 whereas maximum cost of 11,800 euros is seen at mass velocity of 40 kg/m2s.