The present disclosure describes modular fan unit systems and assemblies. A modular fan unit system assembly may include a mounting structure; and a modular fan unit system. The system may include a plurality of modular fan units, each modular fan unit having an outer housing surrounding an internal fan, the modular fan units being configured to be individually separated from the system; a filter housing unit having a plurality of filter compartments, each filter compartment configured to hold an individual air filter, wherein each modular fan unit is mounted and secured to a back side of the filter housing unit such that each modular fan unit aligns with a respective filter compartment; a plurality of louvre units, each louvre unit removably mounted to a front side of the filter housing unit such that each louvre unit aligns with a respective filter compartment; and a controller communicatively coupled with each of the modular fan units, wherein the modular fan unit system is mounted to the mounting structure.