What role do window coverings play in passive solar energy efficiency?

Window Covering Types and Their Applications

Window coverings are essential elements in passive solar house design, serving as a means to regulate the amount of solar radiation entering a building. In general, south-facing glazing should be covered with light-colored, translucent materials during summer months to reflect solar radiation and reduce heat gain. This can be achieved with cellular shades, solar screens, or light-colored curtains.

Window Covering Selection and Placement

When selecting window coverings for a passive solar house, consider the orientation, size, and angle of the windows. For south-facing windows, choose window coverings with a high solar heat gain coefficient (SHGC) to allow for maximum winter heat gain. East- and west-facing windows require window coverings with a lower SHGC to minimize summer heat gain. In general, install window coverings on the outside of the building envelope to improve thermal performance and reduce maintenance.

Window Covering Techniques

In addition to the type and placement of window coverings, consider the following techniques to enhance passive solar energy efficiency: overhangs can be designed to extend at least 1.5 times the window’s width, providing shade for south-facing windows during summer months. This can be achieved with a horizontal or vertical overhang design, depending on the climate and orientation of the building. Thermal mass materials, such as concrete or brick, can be integrated into the design to absorb and release heat, reducing the need for mechanical heating and cooling systems.