Properly sized and installed roof overhangs can most effectively shade south-facing windows from the summer heat. If oriented properly, overhangs will allow the sunlight in through the windows during the winter, providing more warmth to a house.Construction and orientation of an overhang can be tricky since it involves many passive solar design factors:

• Latitude
• Climate
• Solar radiation transmittance
• Illuminance levels
• Window size and type

It’s easy to incorporate overhangs into a home design before or while it’s under construction. Adding an overhang to an existing home, however, can be quite difficult and sometimes impossible. Window awnings, louvered patio covers, or lattice-type panels can be considered as alternatives for existing homes.