The latest and greatest in lighting of all sorts is, of course, LED technology. In regard to residential and commercial lighting, this technology is able to potentially reduce the U.S. energy usage by 75% and the U.S. Department of Energy (DOE) is driving research and development into new breakthroughs in every aspect of the technology. The DOE has calculated that by the year 2030, LEDs have the serious potential of cutting energy use by nearly one half. This would equate to not only energy dollar savings but also reduced carbon emissions. Their unique features of long life, small size, vibration and breakage resistance, good cold weather performance, instant on, dimming ability, lack of ultraviolet and infrared emissions, and color control, all make for numerous benefits in many lighting applications.
Maybe the most notable visual improvement in light output would be the ability to control the color. By that, I mean the color temperature as measured in Kelvin. Those ratings, generally from 2500K to 6000K, determine the visible color of the light which will vary from a “white” which is somewhat yellow, to brighter whites which eventually graduate to “white” light that has a bluish tint. As the Kelvin number increases, the light becomes a brighter “white” and is closer to appearing as natural daylight. Previous to LEDs, there were no color ratings when it came to everyday incandescent lights and they would be at the bottom of the scale. Fluorescent lighting does provide for color control but the intensity of light output and the color rendering index (CRI) is much improved in LED lighting. The CRI is also a trait that, in the past, was not much of a general lighting factor. Now, with LED lighting, the CRI is an important and controllable factor of lighting. This attribute of CRI rating control is important and highly helpful in applications such as retail clothing sales, as high CRI ratings, in concert with Kelvin ratings, are able to reflect true colors as would be viewed in natural daylight. Other great examples of applications that benefit from Kelvin and CRI ratings would be in museums and art galleries, which would also benefit from the lack of the color fading effects of ultraviolet and infrared emissions.
Overall, the appearance of light is described by the correlated color temperature (CCT) which is commonly known as color rendition and affects the perceived color appearance of objects. This color rendition can be calculated by utilizing the CRI rating, although this metric is not the perfect method of determining the fidelity of the lighting, especially in the area of saturated reds, there are numerous other metrics being developed which are able to more comprehensively evaluate color rendering. Generally, a suggested CRI of 80 is the minimum recommendation for interior lighting which is a standard that is easily accomplished with LEDs. The capability of LEDs to exceed CRI ratings in excess of 90 is a groundbreaking improvement over previous technology. A “perfect” CRI rating would be considered 100 and that threshold is within reach with LED lighting and in some cases has even been exceeded.
The fact that LEDs emit their light in a specific direction is another real boon to lighting as they need no reflectors or diffusers which, in the end, lower efficiency. Standard, everyday incandescent bulbs (excluding spot lights) and fluorescent lighting both emit light in all directions. This distribution of light is, obviously, quite inefficient and much of the light is lost due to it emanating in directions which are useless, lost in reflectors that are inefficient in returning all light received, and lost in lights that have diffusers which also diminish the light output. Many types of fixtures using old lighting technology, and diffusers, and reflectors are only capable of emitting 50-60% of the light produced. On the other hand, very close to 100% of light produced by LEDs is useable, and that efficiency is unheard of in the past.
The constantly improving aspects of LED lighting is a major impetus in the R&D push by the DOE. The fact that LEDs are controllable in ways that previous technology is not, is a huge benefit. Controllable features like dimming and other energy saving attributes such as occupancy sensing offer lighting performance and overall value in lighting which, in concert with all the other possible features attributed only to LEDs, all adds up to the improvement of lighting in ways never before achievable.
As always, if you need answers in regard to your LED lighting projects, please feel free to call Polar Ray at 303-494-5773 to speak with a lighting consultant.