<p>This study investigates the thermal and flow characteristics of mono and hybrid nanofluids, specifically TiO₂ and Ag-TiO₂, in a heated duct, aiming to enhance heat transfer efficiency. The novelty lies in utilizing experimentally measured thermo-physical properties in the numerical analysis of both mono and hybrid nanofluids. Results demonstrate a significant augmentation in heat transfer performance by employing Ag-TiO₂ hybrid nanofluids, achieving a maximum Nusselt number enhancement of 40.16% at 0.2% concentration. At a concentration of 0.2%, the thermal conductivity of TiO₂ and Ag-TiO₂ increased by 7.84% and 18.9%, respectively. The Ag-TiO₂ hybrid nanofluid exhibits a maximum viscosity increase in 27% at 0.2% concentration. The study also reveals the superior thermal performance of Ag-TiO₂ hybrid nanofluids, with a thermal performance index (TPI) of 1.33 at 0.15% concentration, surpassing that of TiO₂. Furthermore, entropy generation analysis suggests a reduction in temperature gradient-related irreversibility, highlighting the improved heat transfer efficiency of the hybrid nanofluid.</p>