Shining Through

• By Victor Rivero
• 01/01/11

Most designers engaged in daylighting design understand how daylighting saves energy and influences architecture, but many secondary issues related to daylighting are less understood — factors that can have a significant impact on performance of both the lighting and the quality of the human experience that transpires beneath. What are they — and what can be done to ensure that you get the maximum benefits?

Increased Student Performance
Yes, proper daylighting results in increased student performance. It's true: student performance actually does increase with excellent daylighting. In a comprehensive study of more than 2,000 classrooms over three school districts located in very different climates (San Juan Capistrano, CA; Seattle; and Fort Collins, CO), daylighting conditions were found to have a marked impact on student performance, where some classrooms progressed 20 percent faster than those with the least daylight. In the same study, students in classrooms with the largest window areas progressed 15 percent faster in math and 23 percent faster in reading; students in classrooms with skylights had similarly superior results. Overall, according to an article on the study, "Students in classrooms with the most window area or daylighting were found to have seven percent to 18 percent higher scores on the standardized tests than those with the least window area or daylighting."

Health Benefits
And proper daylighting is even good for your health. Natural light is more plentiful and more well-diffused than that from artificial sources, says Thomas Beck of Colorado-based Beck Architects. Natural light works in "reducing shadows, improving contrast, allowing greater color discrimination, and reducing eye strain — and there's no flicker as with some artificial lights," he observes. But the human benefits don't stop at reducing eyestrain. "Bright light during the day is essential to balance the body's circadian rhythms — the internal ‘clock’ that regulates alertness, concentration, digestion, sleep, and other functions," Beck says. This can help to alleviate insomnia and depression. Exposure to sunlight also produces Vitamin D in the skin and can help avert cancers, diabetes, and multiple sclerosis, and improve mood and lower stress, and thereby increase productivity.  

Design to Avoid Glare
Watch out for glaring problems. According to Gregg Ander (writing for Whole Building Design Guide, a program of the National Institute of Building Sciences), efficient daylighting design indeed provides illuminance levels sufficient for good visual performance, but the design must maintain a comfortable and pleasing atmosphere. "Glare, or excessive brightness contrast within the field of view, is an aspect of lighting that can cause discomfort  to occupants," says Ander. "The human eye can function quite well over a wide range of luminous environments, but does not function well if extreme levels of brightness are present in the same field of view." To combat this phenomenon, Ander recommends avoiding direct beam daylight on critical visual tasks. And if it's too late because you've already built? "The harshness of direct light can be filtered with vegetation, curtains, louvers, or the like" to help distribute light.

Integration With Electrical Controls
Be careful to ensure daylighting integration with electric lighting controls. Good daylighting design doesn't merely complement architectural features, it integrates with the electric lighting system. When sufficient daylight is available, today's advanced controls allow for easy adjustment of electric lighting levels. Switching controls (turn off the lights when there's plenty of daylight), stepped controls (control of individual lamps), and dimming controls (adjust these by modulating power input to complement daylight levels) all play a part.   

Daylight as Design
Finally, set a goal of using daylighting as a central design principle, "not as an add-on feature," says Abby Vogen Horn, director of Energy Efficiency for Franklin Energy Services, a Wisconsin-based company specializing in energy efficiency and renewable energy programs for utilities and states. "Remember, you're smart. Logic can take you a long way down the path: you know what you like in terms of lighting, that you want a connection to the outdoors, that windows and electric lights introduce heat into spaces," she says. "Take what you know, talk to your design team, and set specific goals. Move toward your goals by finding resources, training, and talk with others."

You can also visit www.daylighting.org to find out more.     

Victor Rivero tells the story of 21st-century education transformation. He is the editor-in-chief of Edtech Digest, a magazine about education transformed through technology. He has written white papers, articles, and features for schools, nonprofits, and companies in the education marketplace. He can be contacted at [email protected].