How Light Shelves Make Buildings More Energy-Efficient

Light shelves are flat ledges that run across a window to reflect sunlight into the building. This can save a significant amount of energy that would have otherwise been used on indoor electric lighting. They are becoming popular in settings that must service a lot of people as economically as possible, such as office buildings and healthcare facilities. Reflecting natural light may also help improve the mood of the people inside the building. Seasonal depression is often alleviated with more exposure to natural sunlight. It is estimated that a properly installed set of light shelves can almost double the amount of light penetration in the building's interior.

Building light shelves: Where to install

Light shelves can be installed inside the window, on the outside of the building, or in both places to maximize the amount of light that is reflected. Another option is to use light shelves on the inside of the windowsill and then install shades on the exterior to direct the outside light onto the interior light shelves. Window glazing can be added to the light shelf system to increase the amount of brightness of the light that will be reflected.

Building light shelves: Flat or sloped?

The exact location of the light shelves will affect the amount and quality of light reflected into the building. Various architects have different opinions on which installation style is best, with some preferring a flat ledge and others claiming that a slight slope works better. If a sloped light shelf is used, the angle of the slope should be adjusted to fit with the expected altitude of the sun in that region.

Building light shelves: What surface to use?

The type of surface used for the light shelves will have a major impact on the quality of light they reflect. A brushed metal surface will reflect the most light, but is also prone to causing an unpleasant glare. A rougher surface may produce less glare and will scatter the light particles into many different directions. This allows a rough metal light shelf to reflect light into deep areas of the building's interior where a metal light shelf could not reach.

Building light shelves: Effect of the ceiling

The surface of the ceiling inside the building also affects the effectiveness of light shelves in the windows. The reflected light works best with a white ceiling covered with flat paint. Ceilings that slope downward slightly can cut down on glare and improves the distribution of the reflected light from the light shelves. Exposed ceilings can also work with light shelves, so long as they do not have a lot of colored cables or ducting to deflect the light.