Daylighting Done Right

Incorporating natural light into building design has become an increasingly popular strategy that is dramatically improving energy performance and occupant satisfaction. The use of new glazing and shading systems as well as other daylight-harvesting components and controls is reducing dependence on artificial lighting while helping connect occupants to the outside world.  In fact, some sections of the 2012 International Green Construction Code require that many whole classes of buildings, such as offices and retail, be designed so that at least 25 percent of the regularly occupied square footage is in a daylighting zone with automatic controls. This new requirement is a step in the right direction for energy performance, but it also underscores the need for clear ground rules for best-practice daylighting design. Paula Melton’s article, Doing Daylight Right, in the April 2012 issue of Environmental Building News emphasizes a number of strategies for success as well as potential pitfalls associated with daylighting. Echoing NBI’s position on daylighting design, the article contends that while daylighting can represent an important strategy for reducing energy, it must be done right.

For instance, glazing, while important, shouldn’t be overdone. Otherwise, glare, which can result from reflected light or even diffused daylight may become an issue that creates no only visual discomfort to occupants but can increase energy consumption. “More glazing doesn’t necessarily mean better daylighting,” says Jill Dalglish, president and senior engineer at Dalglish Daylighting. “Extra glazing is not necessary to achieve electric lighting savings with daylight”. Getting the control system right can also make or break a daylighting system. With so many different control systems being developed, the real experts on these systems are actually the manufacturers themselves, according to Dane Sanders, P.E., a principal at Clanton & Associates. Sanders says the job of the design team is to work with the owner to develop the different lighting zones and then ensure that the control system manufacturer (and later the commissioning agent) understands exactly how the occupancy sensors and photo sensors ought to function. “We’re at a time right now that’s pretty exciting,” says Sanders. “There’s a lot of development going on with lighting control systems. The better systems now are networked control systems”.A final consideration in regards to daylighting: the strategy should not be limited to high-profile, high-rises or designer pet projects, especially since the price doesn’t have to be high. “When we in the trade of design and engineering talk about daylighting, too often it seems like it has to be in the context of some tour de force project,” James Benya, P.E., principal at Benya Lighting Design. “The difference we need to make needs to be made in everyday buildings.” This makes sense considering that the sun rises, bringing with it an abundance of natural light, on a daily basis.  “To be successful at daylighting, it has to be in the DNA of the design,” says Todd Reed, daylight designer at 7group. “Perhaps in no other aspect of building performance is an integrated design process so critical to success. Explore the free,  Daylighting Pattern Guide. Quotations were excerpted with permission from “Doing Daylighting Right”, a feature article in the April 2012 issue of Environmental Building News.