Liquid crystal (LC) devices have been used for smart window and see-through display applications. Especially, LC devices which can be used to control the haze value have been studied for smart window applications. LC devices with the polymer structure, such as polymer-dispersed and polymer-stabilized LC cells, can be used to control the haze value. However, for wider applications, it is urgent to overcome disadvantages, such as the high operating voltage, low transmittance in the transparent state, and narrow viewing angle because of the index mismatch between the LC and polymer structure. In this paper, we introduce LC devices based on the electro-hydrodynamic effect. They can provide a high haze in the translucent state because of the turbulence caused by the electro-hydrodynamic effect. They can provide a high transmittance in the transparent state and wide viewing angle because it does not contain any polymer structure. We believe that LC devices based on the electro-hydrodynamic effect can be an excellent candidate for smart window applications.