During warm summer months, overhangs block unwanted direct sunlight from solar glazing, reducing cooling loads.

Locate an overhang above solar glazing (facing the equator – south in northern latitudes and north in southern latitudes) so it does not block the winter sun.

Block the summer sun by extending the overhang approximately:

  • 1/4 the height of the opening at 28°L to 32°L
  • 1/3 the height of the opening at 36°L to 40°L
  • 1/2 the height of the opening at 44°L to 56°L

Exterior horizontal louvers can also be used to shade south glazing. Use the above guidelines to size the louver projection as a fraction of the distance between louvers.

In hot climates (28°L or less) that do not require any heating, extend overhangs, roof, or shading devices to cover the entire solar façade and adjacent outdoor living spaces.

For more detailed information, see the In-Depth Information Pages under Tools + Resources.