Luminaires for decorative lighting and highlighting walls of buildings, stages, parks, plazas and commercial building facades.
Exterior wall-wash lighting is an application where LED products are beginning to emerge. These wall-wash lights are designed for decorative lighting of buildings, plazas, stages, etc.
Outdoor lighting luminaires employing LED technology 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 for developing objective, updated information about the technology. Of the almost 22,000 products listed in the USDOE LED Lighting Facts database as of December 2014, over 6,400 (29%) are commercial outdoor products. Of these outdoor products, there are about 50 identified specifically as wall-wash luminaires with an average efficacy of over 70 lumens/watt.
Energy savings over traditional outdoor wall-wash lighting may be significant—up to 30-75%, depending on design light levels, technology and controls. Lamp life could be significantly longer than other systems in use, making this product especially good in hard-to-access locations. The white light is available in a range of color temperatures. Because of the directionality of LED light sources, LED wall-wash lighting can accurately and efficiently illuminate the desired area. Additionally, the USDOE predicts continued improvement in efficacy and decline in price for LED lighting.
Simple Payback is one tool used to estimate the cost-effectiveness of a proposed investment, such as the investment in an energy efficient technology. Simple payback indicates how many years it will take for the initial investment to "pay itself back." The basic formula for calculating a simple payback is:
The Incremental Cost is determined by subtracting the Baseline First Cost from the Measure First Cost.
For New Construction, the Baseline First Cost is the cost to purchase the standard practice technology. The Measure First Cost is the cost of the alternative, more energy efficienct technology. Installation costs are not included, as it is assumed that installation costs are approximately the same for the Baseline and the Emerging Technology.
For Retrofit scenarios, the Baseline First Cost is $0, since the baseline scenario is to leave the existing equipment in place. The Emerging Technology First Cost is the Measure First Cost plus Installation Cost (the cost of the replacement technology, plus the labor cost to install it). Retrofit scenarios generally have a higher First Cost and longer Simple Paybacks than New Construction scenarios.
Simple Paybacks are called "simple" because they do not include details such as the time value of money or inflation, and often do not include operations and maintenance (O&M) costs or end-of-life disposal costs. However, they can still provide a powerful tool for a quick assessment of a proposed measure. These paybacks are rough estimates based upon best available data, and should be treated with caution. For major financial decisions, it is suggested that a full Lifecycle Cost Analysis be performed which includes the unique details of your situation.
The energy savings estimates are based upon an electric rate of $.09/kWh, and are calculated by comparing the range of estimated energy savings to the baseline energy use. For most technologies, this results in "Typical," "Fast" and "Slow" payback estimates, corresponding with the "Typical," "High" and "Low" estimates of energy savings, respectively.
Status:
Baseline Description: 70W MH lamp Baseline Energy Use: 312 kWh per year per unit
Assuming 95 W (input watts) * 3285 hr/yr / 1,000 W/kW = 399 kWh/yr. Operating hours at 9 hr/day for building exterior lighting. (Navigant, 2012 Pg Table 4.29, pg 54)
"Typical" Savings: 50% Low and High Energy Savings: 30% to 80% Energy Savings Reliability: 6 - Approved Measure
Savings range 30-80%. Typical energy savings is based on replacing the baseline 70W (95W input) MH with an LED fixture consuming 48 W. The assumed replacement was developed based on a review of wall wash products listed on the LED Lighting Facts database with similar, but slightly lower, lumen output. Typically, LED fixtures can provide suitable lighting performance with lower lumen output than the traditional source due to the directional nature of LED lighting.
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.))
Assuming Northwest potential of 4% of national potential (Northwest is about 4% of the population of the U.S.). Assuming national potential of 10% of flood lighting units, based on Navigant's 2011 report for U.S. DOE SSL Program, (Navigant , 2011).
Technical Potential = 4% * 10% * 43,200,000 = 200,000 units.
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): $390.00 Emerging Technology Installation Cost (Labor, Disposal, Etc.): $68.00 Baseline Technology Unit Cost (Equipment Only): $290.00
Costs for wall wash luminaires were developed from an Internet pricing review. The price premium for LED wall wash luminaires as compared to metal halide is about 30%, although prices for LEDs are expected to continue to decline.
Labor costs to replace an existing wall wash with a new LED are estimated at $68, assuming 0.75 hr at $90/hr.
Simple payback, new construction (years): 7.1
Simple payback, retrofit (years): 32.6
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.
DOE, 08/14/2014. LED Lighting Facts U.S. Department of Energy
Navigant , 01/01/2011. Energy Savings Estimates of Light Emitting Diodes in Niche Lighting Applications U.S. Department of Energy, Building Technologies Program
DLC, 01/01/2013. DesignLights Consortium Qualified Products List DesignLights Consortium, Northeast Energy Efficiency Partnerships, Inc.
DOE, 10/02/2013. Solid State Lighting Program U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy
PNNL, 06/01/2012. Demonstration of LED Retrofit Lamps Host Site: Smithsonian American Art Museum, Washington, DC PNNL for DOE Solid State Lighting Program
Navigant, 01/01/2012. 2010 U.S. Lighting Market Characterization U.S. Department of Energy Building Technologies Program
DOE, 12/01/2011. Resources for Outdoor SSL Applications U.S. Department of Energy, Federal Energy Management Program