<p>Solar air heaters (SAH) serve as effective, sustainable thermal systems for low- and medium-temperature applications, yet air's limited heat transfer properties constrain their performance. This study examines the thermal and thermo-mechanical performance of four distinct SAH configurations using computational fluid dynamics (CFD) and experimental methods. The configurations analyzed include a basic flat-plate SAH, a honeycomb-structured absorber plate, a 26°-tilted SAH, and a nano-coated absorber plate with Al₂O₃ particles. Experimental validation conducted at mass flow rates of 0.004 kg/s and 0.006 kg/s demonstrated satisfactory concordance with CFD predictions, exhibiting deviations of 10–15%. Findings indicate that thermal efficiency is positively correlated with mass flow rate across all configurations, with the nano-coated design yielding the highest efficiency of 26.96%, followed by the honeycomb structure. A thermo-mechanical assessment utilizing CFD-derived temperature fields was performed to evaluate thermal strain and stress in the absorber plate. The findings suggest that thermal stresses are within aluminum's permissible limits, but improved heat transfer results in heightened temperature gradients and material stress. The nano-coated configuration, while thermally advantageous, exhibits higher thermomechanical stresses, whereas the honeycomb design offers a more balanced performance with lower stress levels. This research establishes the correlation between thermal enhancement methods and material behavior, providing a detailed framework for improving both efficiency and structural integrity of solar air heaters.</p>