Advancing the effective use of light for society and the environment.

Wednesday, October 13, 2004

Daylight Dividends evaluates school daylighting design in first case study
Photo: Case study cover

The Daylight Dividends program recently released the first of three case studies that evaluate daylighting designs in nonresidential buildings. The first study explores effective design strategies for schools through an assessment of one school built specifically to harvest the benefits of daylight.

Smith Middle School, located in Chapel Hill, N.C., was built from the ground up with daylighting and other environmental features in mind. Incorporating good daylighting practice into the building’s design yielded positive results in energy savings and comfort, as well as a reasonable return on the added investment, says Peter Morante, LRC director of energy programs and principal investigator for the case study.

Design strategy

Image: Roof monitor design
Roof monitor design used at Smith Middle School to bring daylight into the classrooms.

Architects integrated south-facing roof monitors into the school’s design to provide the majority of daylighting within the building. The monitors allow the electric lighting to remain at a low level most of the day, reducing internal heat gains and the need for additional cooling. Cloth baffles within the monitors help distribute the light uniformly and eliminate glare. Fluorescent lighting installed in the classrooms operates on dimming ballasts with photosensors and motion sensors to limit unnecessary electric lighting.

Survey says . . .

Interviews and surveys conducted with the school principal, teachers, maintenance personnel and students indicated a high degree of satisfaction with the daylighting and overall comfort of the school, according to Morante. “Teachers love the amount and quality of light provided by the daylighting scheme. Many times teachers do not even turn on the lights because their lighting needs are met by just the daylighting,” he says. Some maintenance issues were identified, including difficulties with commissioning the lighting controls, cleaning the baffles, and replacing expensive dimming ballasts.

Savings and payback

The case study also documents energy savings and increases that resulted from the daylighting strategy employed at Smith Middle School. Morante noted that the school reduced its lighting energy consumption by approximately 64 percent and its cooling energy by 20 percent through the daylighting design. Heating energy increased by approximately 20 percent because the lighting systems produced less heat. Total energy savings can be used to offset the added costs to build a daylit school, says Morante. “While the cost to construct the school increased, the annual energy costs were reduced, giving the school district a payback of four years for their daylighting investment.”

For more information about Smith Middle School and its daylighting design, download the free case study from the Daylight Dividends Web site.

Daylight Dividends, a program administered by the Lighting Research Center, is a national effort to help people reap the human and economic benefits of good daylighting design in buildings. Daylight Dividends is a program sponsored by the U.S. Department of Energy, New York State Energy Research and Development Authority, California Energy Commission, The Connecticut Light and Power Company, Iowa Energy Center, Northwest Energy Efficiency Alliance, and the North Carolina Daylighting Consortium.

About the LRC

The Lighting Research Center (LRC) is part of Rensselaer Polytechnic Institute and is the leading university-based research center devoted to lighting. Founded in 1988, the Lighting Research Center has built an international reputation as a trusted and reliable source for objective information about lighting technologies, applications, and products. Its mission is to advance the effective use of light and create a positive legacy of change for society and the environment.

2004 Rensselaer Polytechnic Institute, Troy, NY 12180 USA.

Rennselear Polytechnic Institute