The objective of this study is to evaluate the Joule Thomson effect, which occurs at a valve due to the throttling process for mixtures containing polymers and copolymers. For economic and safety reasons, it is essential to know the temperature change in industrial processes due to the pressure drop in the valve. The modeling of this phenomenon in mixtures containing polymers and copolymers, however, remains a challenge for process engineers, and the literature rarely reports studies on the subject. This work proposes a model that can directly compute temperature due to the throttling process using the concept of residual enthalpy and the perturbed-chain statistical associating fluid theory equation of state, instead of solely computing the Joule Thomson coefficient. Systems containing poly(ethylene-co-vinyl acetate) and low-density polyethylene were chosen as case studies because of the need for temperature control at the reactor outlet and separation processes. The model prediction was validated using industrial data, and deviations of approximately 2% between the model prediction and the experimental temperature indicate the efficiency of the proposed approach when describing the temperature due to the throttling of both systems that are being studied.