Architects and designers live with trade-offs every day, often faced with difficult choices between clients’ needs and artistic conception, value and aesthetics, savings and durability.
Until recently, LED lighting, a technology employing little red, green and blue light-emitting diodes, was one of those catalysts for consternation, particularly with regard to general lighting needs.
With up to 30 times the life span of incandescent fixtures, the small, heatless light source clearly offers greater efficiencies, reduced maintenance and lower cooling costs compared to traditional lighting. Smart building owners demand LEDS, energy experts tout them, and LEED projects often require them to make the grade.
But here’s the catch. Historically, the quality of output for LEDs, created when electricity is run through semi-conductor material, has not lived up to architectural standards, which are measured in terms of the warmth and reliability of incandescents. LEDs were plagued by a lack of standardization in color and lifespan, due in part to the nature of their origins.
A crossover from the electronics industry, many early LED manufacturers understood more about semi-conductors than they did lighting, resulting in some inferior products coming to market. This was especially true for white LED fixtures, produced when phosphor lenses or coatings are added to blue.
Fortunately, with recent advances in color output and the advent of accepted standards in color and lifespan definition, the quality and dependability of LEDs are catching up to their efficiencies. And architects are taking notice.
While early LED whites were often blue in appearance, improvements in the use of phosphors have produced a range of nuanced whites that more closely match traditional technologies, and are superior to fluorescents.
Some newer LED fixtures also employ multiple shades of white to afford “dynamic white” color tuning or “warm dimming,” respectively, allowing precise adjustment of white tint or a dimming profile that mimics the tendency of incandescent and halogen sources to warm in color when dimmed, i.e. to go from a white to a more yellow/orange hue at low light levels. This warm-glow dimming capability has made LEDs particularly popular in residential and hospitality applications.
Along with enhancements in phosphor technology, color standards defined by the American National Standards Institute (ANSI) are ensuring more consistent production, binning and labeling of LEDs. The standards, based on correlated color temperatures (CCTs) or the color an object would glow when heated to a certain temperature, are the same standards used for more traditional lighting, providing the buyer a basis of comparison.
For example, a candle is about 1,800K, incandescent light about 2,700K, and an office-grade fluorescent approximate 3,500K. LEDs are now available in a broad range, standardized in increments between 2,200K and 5,000K, so specifiers can find LEDs that are at the warmest and coolest (most like daylighting) ends of the spectrum. In addition, an accepted definition of LED lifespan, described as the point at which the light source is reduced to 70% of its initial output, and uniform methods for testing have been implemented.
Architects have long specified LEDS for specialized cove, façade and backlighting applications due to their small size and typically wide light distribution, but advances in output and standardization are moving the technology—once limited to the realm of specific tasks—to an archetype for general lighting, closing the chasm between efficiency and light quality.