- This study presents a novel approach towards achieving high luminous transmittance (Tlum) for vanadium dioxide (VO2) thermochromic nanogrid films whilst maintaining the solar modulation ability (ΔTsol). The perforated VO2-based films employ orderly-patterned nano-holes, which are able to favorably transmit visible light dramatically but retain large near-infrared modulation, thereby enhancing ΔTsol. Numerical optimizations using parameter search algorithms have implemented through a series of Finite Difference Time Domain (FDTD) simulations by varying film thickness, cell periodicity, grid dimensions and variations of grid arrangement. The best performing results of Tlum (76.5%) and ΔTsol (14.0%) are comparable, if not superior, to the results calculated from nanothermochromism, nanoporosity and biomimic nanostructuring. It opens up a new approach for thermochromic smart window applications.