LED Outdoor Lighting
The lighting of outdoor areas with LED lighting is becoming more and more prominent. A study in which the areas of focus were outdoor roadways and area luminaries, parking garage luminaries, canopy luminaries (gas station covers, etc.), and directional luminaries (floodlights, accent lights, wall packs, etc), produced some results that show that the improvement in the past few years has been pretty great, but the future will be even brighter. Pun intended. Seriously, with outdoor lighting being a huge contributor to energy use in this country, the continued transitioning of this segment to LED technology is an important factor in the overall transition to solid state lighting (SSL). However, in this field, there is some competition, as high-pressure sodium lights are quite efficient in their own right. With the rapidly changing LED field, the well-designed LED luminaries do pose a more efficient profile when it comes to overall lifetime expectancy and overall lower maintenance and energy costs. The outdoor LED luminaries will also display a nicer color quality than either high-pressure sodium or metal halide lighting.
The overall efficacy of outdoor area lighting has continued to increase, and the mean performance now stands at approximately 80 to 90 lm/W and the highest outputs range from 120 to 150 lm/W. Lumen output has continued to increase and, as with other LED lighting, the outdoor lighting arena has continued to see an average annual increase of 10 lm/W. Luminaries for use in parking garages, canopy lighting and directional lighting all had quite similar ranges regarding lumen output and efficacy. The range of most products was between 2,000 lm and 11,000 lm, with the lm/W rating standing between 70 and 110. About 78% of the parking garage luminaries had a lumen output of at least 2,000 lm and efficacy of 75 lm/W. Nearly 77% of the canopy luminaries were also within those ranges but tended to exceed 80 lm/W. Today there are numerous products which list lumen output that would be comparable to a 400-watt high-pressure sodium street light. This was not a possibility just a few years ago. The early editions of LED outdoor lighting also had a tendency to lean more toward the higher end of the CCT spectrum and were often in found to be in the 6500 K area. The more recent LED powered area lighting luminaries tend to be in the 4000 K to 5000 K range. More than 40% of area/roadway luminaries had a nominal CCT of 4000 K, while almost 60% had a CCT of 4500 K or less. The canopy lighting luminaries showed the highest mean CCT at 4823 K, followed by parking garage luminaries at 4685 K, directional luminaries at 4641 K, and the area/roadway luminaries at a mean CCT of 4568 K. The reason the canopy luminaries were shown have a 10% higher mean efficacy than any of the other three types in the study was not exactly known but it was thought that the different optical systems used by the canopy luminaries may have played a major part.
These four types of luminaries are the main products used to light large areas or surfaces outdoors. Of the four, dating back to projects in 2007, LED roadway lighting was one of the first categories to see numerous competitive products on the market. The early products were certainly inferior to what is available on the market today, but they were the starting point for the energy saving upgrades being made today in the fields of outdoor lighting. Since 2009, roadway and parking garage luminaries have exhibited over a 50% increase in efficacy, and since they were listed as the lowest of the four, in terms of efficacy, the increases are a nice improvement. The increases in the roadway lighting arena are quite likely due to the amount of competition in that field. Once again proving that the more competition there is, the better the product eventually becomes.
The use of LED lighting in all these four areas has continued to grow at an increasing rate over the past few years. The rate of conversions to LED luminaries for all types of outdoor lighting will only continue as older technology lighting comes to its life’s end and as property owners and municipalities make the decision to make the LED conversion as an overall money saving improvement. However, as with all aspects of LED lighting at this point in the development, there are inferior products in the marketplace and manufacturers’ reputations and end users’ needs and applications must be understood in order to make a decision that will result in the correct, desired, and expected performance levels.
As always, if you have questions in regard to any of your lighting projects, please feel free to call Polar-Ray at 303-494-5773 to speak with a lighting consultant. Thank you for perusing our web site.