In present day passenger cars, Mobile Air Conditioning (MAC) system is one of the essential features due to rise in overall ambient temperatures and comfort expectation of customers. During the development of MAC system, the focus is on cooling capacity of system for maintaining in-cabin temperatures. However, parameters like solar radiation, air velocities at occupant, relative humidity, metabolic rate and clothing of occupants also influence occupant’s thermal comfort and normally not considered in design of the MAC system.Subjective method is used to evaluate thermal comfort inside vehicle cabin which depends mainly on human psychology. To better understand the effect and minimize the human psychological factors a large sample of people are required. That process of evaluating the comfort inside the vehicle cabin is not only time consuming but also impractical. To address this, a thermal comfort evaluation model which predicts Percentage People Dissatisfied (PPD) is derived and modified from a model available for room AC system.This study focusses on defining a process and establishing a model for evaluating the influence of critical parameters like solar radiation, air velocities, and relative humidity. on passenger thermal comfort inside passenger cabin. Also extensive study is carried out to check the authenticity and correlation of the model in dynamic running condition by taking the subjective feedback. This model is not only used for evaluating MAC performance but also for optimizing and refining the dominating factors affecting thermal comfort.