Today, after decades of conspicuous energy and material consumption, escalating energy and construction costs and the desire to be more environmentally sustainable are forcing designers to rethink their strategies and to ask how we can do more with less. More stringent energy codes and LEED energy targets are among the most challenging of all of the pressures facing us. For lighting designers, it is harder than ever to create pleasing spaces that meet the expectations of the owner, architect, and users with considerably less wattage per square foot.
The lighting community is responding to the need to reduce energy consumption in different ways. Some are focused on improving fixture efficiency, particularly for fluorescent fixtures, which is, of course, a fundamentally very good and necessary development. There are far too many commercial-grade fixtures on the market that are still in the 50% to 70% efficiency range.
Then there are those who focus on light source efficacy as the answer to the industry’s problems. Many are convinced that super-efficient, low-wattage LED fixtures in various arrays are the be-all and end-all cure for our energy problems. Just as the push to improve fixture efficiency is essential, the need to develop improved LED products and other high-efficiency sources is inarguably important.
The danger here is becoming so fixated on fixture or source efficiency that people lose sight of the most important objective in lighting design, which is to create quality luminous environments for people, as opposed to for power-density targets. An energy-efficient design isn’t necessarily a quality design. As many designers have remarked, a bad lighting design made more efficient is still a bad design. So many people are rushing to get LED products on the market that corners are being cut in terms of glare control, color temperature, and overall dependability. In the end, a glare-producing LED downlight that sacrifices light quality and fixture dependability for the sake of efficiency or cost is no more desirable than an inefficient fluorescent downlight.
Before designers even consider fixture efficiencies or source efficacies, they should first evaluate application efficiency. This frequently overlooked attribute describes how proposed lighting strategies interact with the overall materials and building components in a space, in terms of reflectance, absorption, and distribution. For example, using an uplight, however efficient the fixture may be, to illuminate a dark wood ceiling is an incredibly inefficient strategy to achieve a comfortable ambient light level throughout a space. Application efficiency, in effect, compares the design of the space itself to that of a fixture or optical system.
After the lighting concepts on a project have taken shape and the fixture selection and specification process begins, the designer must then take the time to review photometric reports and make sure that products under consideration are as efficient as reasonably possible for that particular application. In some cases, manufacturers may offer modified versions of fixtures that offer better efficiency.
Next, get samples of any new LED products being considered and test them out for glare control, color temperature and color rendition, multiple shadow problems, modular design that enables future servicing of key components, and serious heat sink design for longevity.
Common sense, practical applications, and due diligence need to prevail to produce lighting that is as pleasing and reliable as it is sustainable.
Photo Credits: Stephen M. Lee (1); Ste3ve (2); Ned Goodell / Machado and Silvetti Associates (3)