<p>This study presents a novel design approach for enhancing the performance of H-type Darrieus wind rotors (H-rotors), specifically targeting their low self-starting torque. The approach combines the synergistic effects of incorporating auxiliary airfoils with varying aspect ratios. A coupled wind tunnel experimental and computational fluid dynamics (CFD) approach is employed to achieve comprehensive insights. Wind tunnel experiments measure starting torque and power output of H-rotors with different aspect ratios (<i>A</i>_R = 0.9 to 1.1) and wind speeds (4–8&#xa0;m/s) with and without NREL S823 auxiliary airfoils. The results demonstrate a consistent trend: the coefficient of static torque (<i>C</i>_ts) increases with decreasing aspect ratio (<i>C</i>_{ts, AR=0.9} &lt; <i>C</i>_{ts, AR=1.0} &gt; <i>C</i>_{ts, AR=1.1}). Notably, the addition of auxiliary airfoils significantly improves self-starting capability by doubling the starting torque compared to the baseline H-rotor. Furthermore, the power coefficient (<i>C</i>_p) exhibits an 18.8% increase with the auxiliary configuration. CFD simulations elucidate the underlying mechanisms for the performance enhancement. The simulations reveal that the auxiliary airfoils significantly influence the aerodynamic behaviour by, managing the boundary layer, delaying flow separation, creating a more uniform pressure distribution over the blades. These combined effects contribute to the synergistically superior performance of the H-rotor with auxiliary airfoils.</p>