The effective draft temperature (EDT) is commonly employed to assess air distribution performance in terms of thermal comfort. The traditional EDT’s applicability is restricted to air velocities below 0.35 m/s. Nevertheless, air velocities can be increased to as much as 0.80 m/s to achieve energy efficiency. This chapter expands the EDT to cover the entire spectrum of air velocities. The conversion factor of air velocity to air temperature for the proposed extended EDT is determined by the cooling impact of air movement (calculated from the standard effective temperature). Meanwhile, the reference state and the upper/lower limits of the proposed extended EDT are defined based on thermal neutrality and the thermal comfort boundaries (calculated from the Predicted Mean Vote), respectively. Experiments conducted in a stratum-ventilated office with higher air velocities are utilized to validate the proposed extended EDT. The results demonstrate that the conventional EDT has an average accuracy rate of 69.6%. The existing extended EDT (with an average accuracy of 71.7%) outperforms the conventional version by 3.1%, while the proposed extended EDT (with an average accuracy of 97.8%) shows a 40.6% improvement. The proposed extended EDT values for Categories I–III of thermal comfort under both cooling and heating modes are presented in tables to facilitate practical applications.