A molecular cooling fan (MF) is a nanocomposite coating technology, where the quantized lattice motions in nanomaterials are assembled to absorb heat from the heat source, promote to higher vibration states, and emit excess energy by radiation. Using a factorial design technique, seven factors were investigated to optimize MF cooling performance and efficiency. The results show that a MF coating prepared with 8 nm sized multiwalled carbon nanotubes can cool down 4 degrees C lower than that assembled with 50-80 nm due to higher activity of lattice motions. The MF makes equilibrium temperature cool down by 10 and 20 degrees C at input operation voltages of 35 and 55 V on the same heat dissipation unit (HDU). Using the optimal factors, a MF coating was applied on commercial HDUs. The results demonstrated that molecular fan action can reduce the size and mass of the heat-sink module, offering a low cost LED light unit.