Which shading strategy is best for shading from sun angles coming from east and west?

• A. Louvers parallel to the wall (Horizontal types)
• B. Vertical type of Sun Shading device
• C. Eggcrate types sun shading device
• D. Combination of horizontal vertical types and their masks

Answer: (B)

Shading devices should be aligned with the sun’s path to block direct rays effectively. When the sun comes from the east or west, its rays hit the facade almost horizontally. Vertical shading fins extend out from the wall in that direction and intercept those horizontal rays across a wide range of morning and afternoon angles. They cast shadows on the wall that reduce direct solar heat gain and glare while still admitting diffuse daylight between the fins.

Horizontal shutters or louvers are more suited to sun from the south, where the sun climbs higher in the sky and horizontal blades block the vertical component of the rays. A grid or eggcrate can shade from multiple directions but tends to cut down daylight more and can complicate design without providing a targeted benefit for side sun. A vertical shading strategy on east and west facades thus offers the most direct, efficient control of side-sun heat and glare.