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Natural Daylighting:
Invigorating and Productive

The term “daylighting” describes the illumination of buildings by natural light, which can be accomplished through the use of windows, skylights, and any other openings or reflective surfaces used in building design. These surfaces in turn provide effective internal lighting, resulting in energy savings and an overall “greener” building due to reduced artificial light use.

Natural light is free and daylighting can replace electric light for 70 to 80 percent of daylight hours, saving money and energy. In addition, studies have proven that daylighting is strongly correlated to substantial improvements in human performance in retail, workplace, and educational facilities.

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Daylighting is proven to increase productivity and the overall satisfaction of employees, students, clients, and retail customers. This is due to the visually invigorating and productive environment that natural light provides.

Windows are the most common way of admitting natural light into a space. Different types of window treatments and grades of glass affect the amount of light transmission through the window. Other methods of daylighting include: clerestory windows, skylights, light shelves, light tubes, sawtooth roofs, heliostats, smart glass, fiber-optic concrete wall, hybrid solar lighting, and solariums.


Daylight Planning
One of the first things to consider in a daylighting plan is the cost. Fortunately the potential return on investment is high: the money put into incorporating a daylighting system into a building design can be made up over time by the reduction of the building’s total energy costs. In addition, windows can increase the value of a rental space, increasing revenue.

However, a daylighting plan is more sophisticated than simply determining window size and location. An in-depth analysis should be performed, taking into account the amount of light received through polar-side windows from the autumnal equinox to the spring equinox, as well as equatorial-side windows that receive light nearly every day of the year. It is important to take this information into consideration because the area adjacent to your equatorial-side windows is the area that will have effective daylight.

Seasonal factors come into play as well, such as the highly directional light of mid-winter that casts deep shadows. All of these factors, and many more, need to be considered in order to maximize the effectiveness of the proposed daylighting plan. Simulation software is available to help builders and architects reach the full potential of their proposed plan, including Velux Visualization Software, Radiance, Dayism, and Lightsolve and more. These daylighting simulation tools aid in daylighting design and analysis by predicting and documenting daylight levels prior to commencing a building design. For more information about simulation software, visit www.thedaylightsite.com.

Positive Effects of Daylighting
Studies performed by the United States Environmental Protection Agency have shown that on average we spend about 90% of our day inside buildings. According to the magazine Environmental Design & Construction, owners of buildings with daylighting systems are overall more satisfied with their investment. Daylighting systems offer an increased return on the owner’s investment through the building’s increased overall asset value. Designing a building with a daylighting plan should not cost more than a standard construction project, especially due to a decreased HVAC equipment budget.

Installing daylighting systems into your building gives everyone in it the potential to be healthier, more satisfied, and more productive. For more information on the benefits of daylighting, see 31 Advantages of Daylighting.
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The Guardian Solution
Guardian provides a number of products within our SunGuard line that could be part of a complete daylighting system. Our advanced architectural glass solutions offer a variety of energy-efficient low-emissivity coated glass products with light transmission from 8% to 78% and high color rendering indexes that allow designers the ability to provide ample visible light with more accurate color transmission to connect the occupants to the outdoors and enhance the experience of the space. The goal is to provide glass that is environmentally responsible and regulates a healthy atmosphere to work and live in. Guardian glass products may also contribute toward LEED points for a project.

SunGuard’s SuperNeutral, High Performance, and Solar series of high performance architectural glass help designers create striking statements of light and color while controlling energy costs. Guardian spectrally selective glass reduces long (ultraviolet) and short (infrared) wave radiation, while at the same time allowing visible light to be transmitted through the glass:

  • SuperNeutral products deliver high light transmittance while reducing solar heat gain. Their neutral appearance is the most similar to clear uncoated glass. Guardian offers five SuperNeutral Low-E glass products, available in a variety of colors and performance levels. This glass is the ideal solution for energy-efficient commercial structures.
  • High Performance Low-E products offer a variety of appearances combining medium to high visible light transmission and varying levels of reflectivity, with low solar heat gain. There are six products available on a variety of clear and tinted substrates to provide the perfect High Performance glass to suit your needs.
  • Solar Control products specialize in blocking heat. They are not Low-E glass and have a more reflective appearance and the lowest solar heat gain. Guardian offers SunGuard Silver 20 on clear and green float glass substrates for solar control.


With today’s emphasis on sustainable design and daylighting, architectural glass that offers high levels of visible light transmittance, while controlling heat, are in demand. Guardian SunGuard will help build with light – and keep your project on the leading edge of sustainable and productive building design.

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