LED Outdoor Wall-Mounted Area Luminaires
Outdoor Wall Mount Lighting: LED vs. HID
Designed to light walkways and building entries and provide security lighting for areas adjacent to buildings. Wall-mounted area luminaires using LED lamps are becoming widely available.
Item ID: 395
Technical Advisory Group: 2012 LED Lighting TAG (#5)
Average TAG Rating: 3.5 out of 5
TAG Ranking Date: 04/05/2012
TAG Rating Commentary:
- For wall packs, attention to glare important consideration.
Exterior wall-mounted security lighting is an LED application that is gaining traction. These luminaires are designed to light walkways and building entries. Because of the directionality of LED light sources, LED wall-mounted area luminaires can deliver uniform lighting on the ground while minimizing or eliminating light pollution.
Outdoor LED luminaires are widely available from a number of manufacturers. The U.S. Department of Energy (USDOE) is encouraging research, development, and market penetration of the technology, and is providing resources to develop objective, updated information about the technology. As of early 2015, over 1,300 LED wall-mounted area luminaires were listed in the USDOE LED Lighting Facts database. (U.S. DOE, 2013).
Energy savings over traditional outdoor security lighting may be significant – 30% to 75% – depending on design light levels, technology, and controls. LEDs are particularly well-suited to operate with automatic controls, such as photo sensors and occupancy sensors, which allow light output and power consumption to be reduced during periods of low occupancy. Lamp life could be significantly longer than other lamps in use, making LEDs especially good in hard-to-access locations. The use of "self-cleaning glass or coatings" on fixtures could reduce the need for cleaning, which would make the most of long-life and reduced maintenance claims. The white light is available in a range of color temperatures. Light distribution can be precisely controlled, often providing more uniformity than other technologies. The USDOE predicts that the efficacy of LED lighting products will continue to improve while prices continue to drop (EERE, 2011), (EERE, 2012).
Retrofit kits for existing luminaires are also available. Well-designed retrofit kits can deliver the same benefits of integral luminaires.
Baseline Description: HPS wall mounted area luminaire
Baseline Energy Use: 416 kWh per year per unit
Baseline use assumes a 70 W HPS (95 W total) luminaire operating 4380 hr/yr.
Manufacturer's Energy Savings Claims:
"Typical" Savings: 70%
Savings Range: From 50% to 75%
Manufacturers claim savings of 75% and greater.
Best Estimate of Energy Savings:
"Typical" Savings: 58%
Low and High Energy Savings: 30% to 75%
Energy Savings Reliability: 3 - Limited Assessment
Energy savings will depend primarily on the LED wall-mounted area luminaire selected to replace an existing luminaire and the type of luminaire that is replaced. Selecting an appropriate LED luminaire is not a matter of simply matching lumen output; because of the more directional nature of LED sources, LED wall-mounted area luminaires can often provide equivalent lighting performance using fewer lumens than conventional sources. Energy savings will be maximized by selecting an LED luminaire that delivers the necessary illuminance in the target area with appropriate lighting quality for the lowest power density. Energy savings will also depend on LED luminaire quality and longevity, proper installation of the LED lighting system, whether controls are included in the system, and what kind of controls are used.
DOE CALiPER studies have demonstrated energy savings. (US DOE, 2010)
Energy Use of Emerging Technology:
174.7 kWh per unit per year
Energy Use of an Emerging Technology is based upon the following algorithm.
Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))
The energy use of the LED luminaire assumes a 40W LED operating 4380 hr/yr.
Potential number of units replaced by this technology:
Based on estimated 15 MWa base load in BPA region
Regional Technical Potential:
0.08 TWh per year
Regional Technical Potential of an Emerging Technology is calculated as follows:
Baseline Energy Use * Estimate of Energy Savings (either Typical savings OR the high range of savings) * Technical Potential (potential number of units replaced by the Emerging Technology)
Installed first cost per: unit
Emerging Technology Unit Cost (Equipment Only): $300.00
Emerging Technology Installation Cost (Labor, Disposal, Etc.): $40.00
Baseline Technology Unit Cost (Equipment Only): $150.00
Based on prices available through Internet lighting distributors, the cost of LED wall packs range from $200 to $800 and the cost of conventional HID wall packs range from $150 to $500.
LED Price source: http://www.prolighting.com/ledwali.html
HPS Price source: http://www.prolighting.com/hpswali.html
Installation cost is the author's estimate of approximately 0.5 hr @ $70/hr plus disposal.
Retrofit kits can be lower cost than integral luminaires, but not always as the price of integral luminaires continues to decline. In addition, depending on the design of the retrofit kit, the labor hours required to gut an existing housing and install a retrofit kit may be greater than the labor hours required to simple replace the entire luminaire.
Simple payback, new construction (years): 6.9
Simple payback, retrofit (years): 15.7
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.
No independent evaluations of the cost effectiveness of LED wall-mounted area luminaires were found. In general, however, cost effectiveness will vary based on a variety of factors, including the electricity rate, maintenance savings estimates, fixture cost and new construction versus retrofit scenarios. Independent field assessments of LED lighting in other outdoor applications have shown a wide range in simple payback periods, from a high of 15 years to a low of 3 years, where avoided maintenance costs are significant and controls are incorporated to maximize energy savings.
In addition, cost effectiveness is expected to improve as LED prices continue to decline. The estimated cost trajectory for LED lighting is well documented by the DOE. Prices are anticipated to drop by approximately 85% between 2010 and 2020, from $181/klm to $24/klm.
Wall-mounted area luminaires are designed to light walkways and egress areas and provide security lighting for areas adjacent to buildings. With advances in LED lighting technology, wall-mounted area luminaires using LED sources are becoming widely available. The most common type of wall-mounted luminaires is commonly referred to as a “wall pack.”
Retrofit kits for existing luminaires are also available. Well-designed retrofit kits can deliver the same benefits of integral luminaires. Retrofit kits typically include a complete LED lighting system, including LED modules and/or arrays, optics, driver, and mounting hardware. Retrofit kits can be lower cost than integral luminaires, but not always as the price of integral luminaires continues to decline. Retrofit kits allow reuse of existing housings, which can be of particular benefit for some applications. On the other hand, lumen maintenance, thermal management, light distribution, and physical mounting can be of concern for retrofit kits, as the design must allow for proper operation in a wide variety of housings. For reliable performance, utilize retrofit kits certified for compatibility with the specific make and model number of the existing street lights.
Traditionally, wall-mounted area luminaires have used high-intensity discharge (HID) sources, such as metal halide (MH) and high-pressure sodium (HPS) lamps, as well as fluorescent sources.
LED wall pack lighting has advanced rapidly in recent years, tracking advancements in LED lighting in general. LED wall-mounted area luminaires are widely available from a significant number of manufacturers.
As of early 2015, over 1,300 LED wall-mounted area luminaires are listed in the USDOE LED Lighting Facts database. The Design Lights Consortium includes LED wall-mounted area lights on its Qualified Products List (DLC, 2013), (U.S. DOE, 2013).
The USDOE Commercially Available LED Product Evaluation and Reporting (CALiPER) Program tested LED wall-mounted area luminaires as well as traditional HPS and MH products (as baseline) in their 2009 Round 10 report (US DOE, 2010). Results show that the LED products were generally more efficacious than the benchmark products, but not always. In addition, LED products were found to be capable of meeting or exceeding the light output and efficacy of benchmark products while providing more uniform light distribution. However, a wide range of performance was measured for LED wall-mounted area luminaires and not all models demonstrated these capabilities. CALiPER tested additional wall-mounted area lights in their 2011 Round 13 report and the products showed an average overall improvement in efficacy of about 20%.
LED luminaires promise long life and robust design. In addition, only a gradual reduction in light output is expected over time, not sudden catastrophic failure, which reduces maintenance costs and can significantly reduce the simple payback period. Environmental benefits include no mercury content, so disposal issues and costs are reduced compared to most of the competing technologies. LED “white” light is available in a range of color temperatures. Light distribution is more even than that of most other technologies, sometimes allowing lower light levels or greater fixture spacing while still providing better visibility than traditional sources. LED sources are inherently controllable, without experiencing life degradation with frequent switching. LED lamps eliminate for additional emergency lights in case the power supply is momentarily interrupted, as is the case with HID lamps.
End User Drawbacks:
Product quality: Studies such as DOE CALiPER reports demonstrate that product performance and application suitability vary widely. One particular concern is the shorter life of LED lamp drivers, which may need to be replaced long before the lamp does. Product quality is highly variable and is changing rapidly, so it is important to carefully research and review available information to assess quality, performance, and overall value at the time of purchase. Product qualifications for LED exterior lighting, available through organizations such as the DesignLights Consortium, can be useful in vetting product quality.
First cost and cost effectiveness: LED products can be more expensive than the incumbent lighting technologies. Costs are expected to decline due to technological advances and increased demand, and cost reductions are evident in the marketplace. Evaluating LED luminaires based on total cost of ownership will take into account potential non-energy benefits, such as maintenance savings, which will improve the cost-effectiveness analysis.
Operations and Maintenance Costs:
LED sources promise long life with slow lumen depreciation, which could result in lower maintenance costs and longer intervals between product replacements. Typically, assessments of LED lighting have assumed zero regular maintenance costs over the course of their useful life because the technology is very robust and periodic replacement of light sources is not anticipated. However, it may be more realistic to assume some minimal regular maintenance cost for periodic cleaning. The amount of cleaning depends on the application environment. A better understanding of maintenance issues will be gained through experience with long-term operation of LED luminaries.
Anticipated Lifespan of Emerging Technology: 15 years
The useful life of LED technology is typically expressed in terms of lumen maintenance, most often as the number of hours until the lumen output has dropped to 70% of the initial light output (commonly referred to as L70). Well-designed LED wall-mounted area luminaires are expected to have an L70 life of 50,000 to 100,000 hours. Assuming an operating cycle of 11 hours per day, this translates to approximately 15 to 30 years of daily operation.
It is important to note, however, that a fixture may fail before the light source has reached its end of life, due to failure of another component of the fixture such as the electronics – particularly the driver, materials, housing, wiring, connectors and seals. This is true for fixtures with conventional sources as well as those with LED sources, but is likely to be more of an issue for LED fixtures given the very long life of the source.
The effective life of well-designed retrofit kits is expected to be equivalent to that of new luminaires, however can be impacted by the housing in which the retrofit kit is installed. The DLC specifies a minimum required lumen maintenance for retrofit kits that is equal to the minimum required lumen maintenance for new luminaires. This lumen maintenance must be demonstrated in a representative housing.
Wall-mounted area luminaires are available with various light sources, most commonly HID sources (such as MH, ceramic MH and HPS lamps) and also induction sources.
Reference and Citations:
Solid State Lighting
U.S. Department of Energy, Energy Efficiency & Renewable Energy
LED Lighting Facts
U.S. Department of Energy
2010 US Lighting Market Characterization
Navigant Consulting, Inc.
Energy Savings Potential of Solid-State Lighting in General Illumination Applications
Navigant Consulting, Inc.
Energy Savings Estimates of Light Emitting Diodes in Niche Lighting Applications
U.S. Department of Energy, Building Technologies Program
Exterior Lighting for Energy Savings, Security and Safety
Pacific Northwest National Laboratory
New and Underutilized Technology: Exterior LED/Solid State Lighting
Energy Efficiency & Renewable Energy
Demonstration Assessment of Light Emitting Diode (LED) Walkway Lighting, Host Site: Federal Aviation Administration, William J. Hughes Technical Center, Atlantic City, New Jersey
U.S. Department of Energy
Straight Talk about LED Luminaires
Technical Brief Understanding LM-80, Lumen Maintenance, and LED Fixture Lifetime
Philips Color Kinetics
DesignLights Consortium Qualified Products List
DesignLights Consortium, Northeast Energy Efficiency Partnerships, Inc.
DOE Solid-State Lighting CALiPER Program Summary of Results: Round 10 of Product Testing
U.S. Department of Energy