The slats can be vertical or horizontal. Louvers remain fixed and are attached to the exteriors of window frames. Shutters are movable wooden or metal coverings that, when closed, keep sunlight out. Shutters are either solid or slatted with fixed or adjustable slats. Besides reducing heat gain, they can provide privacy and security.
Some shutters help insulate windows when it is cold outside.
Rolling shutters have a series of horizontal slats that run down along a track. These are the most expensive shading options, but they work well and can provide some security. Many exterior rolling shutters or shades can be conveniently controlled from the inside. One disadvantage is that when fully extended, they block all light. Solar screens resemble standard window screens except they keep direct sunlight from entering the window, cut glare, and block light without blocking the view or eliminating air flow.