Crown molding runs along the perimeter of the ceiling and adds a decorative flair to your chosen room that can create richness and depth. But if the room has low ceilings and is relatively small, adding crown molding also has another benefit: It can actually make the room seem taller and larger. The best crown molding for low ceilings should be smaller than 4 inches in width and have a paint color that is either the same color as the wall or a lighter color. A unified color scheme will help to create the illusion of height, tricking the eye.