Rejuvenators are added to reclaimed asphalt pavement (RAP) binders to enhance their low-temperature and fatigue performance. The effectiveness of a rejuvenator depends upon many factors, including the properties of the rejuvenator as well as the compatibility between the rejuvenator and the base binder. The thermal properties of a rejuvenator can vary greatly based on its chemical composition. This research focuses on understanding the effects of the thermal properties of rejuvenators on the rheological properties of the rejuvenated binders, particularly in relation to the critical low temperature. In this research, an extracted and recovered RAP binder was blended with two different rejuvenators at a dosage of 10% by weight of the binder and the change in the critical temperatures was assessed using rheological measurements. Differential scanning calorimetry (DSC) was used to obtain the crystallization and melting points of the rejuvenators before and after aging. Modulated differential scanning calorimetry (MDSC) was also used to assess the change in the glass transition temperature of the control base binder and the rejuvenated RAP binders as well as to identify crystallization and melting events. The results provided useful insight into the changes in the properties of rejuvenators with aging through the use of DSC. It also highlighted the effect of the crystallization and low-temperature flow properties of the rejuvenators on the performance of rejuvenated binders.