This study investigates the aerodynamic performance of a micro vertical-axis wind turbine (VAWT) by comparing the baseline NACA 0018 airfoil with the S822 airfoil using computational fluid dynamics (CFD). The novelty of the study lies in validating a transient two-dimensional sliding-mesh CFD framework and using it to compare a conventional VAWT airfoil with a dedicated small-wind airfoil while identifying the shift in the effective operating tip-speed ratio (TSR) range. A comparison with published CFD data showed good agreement, with a root mean square error (RMSE) value of 0.0176 and R² of 0.48 for the compared power coefficient points. The NACA 0018 airfoil and the S822 airfoil achieved a peak power coefficient of 0.2635 and 0.2077, with a TSR of 2.3477 and 2.6147, and peak average torque of 6.358 N · m and 4.500 N · m, respectively. Further, for the S822 airfoil, the comparison showed that the effective operating range shifted toward higher TSR values. These findings confirm the importance of airfoil selection for micro VAWT applications and verify its suitability for future optimization in urban and low-wind-speed environments.