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Bright savings.

Industry experts estimate that nearly 80 percent of the cost of owning and operating a lighting system is in energy costs. When looking for ways to increase energy efficiency, a lighting retrofit is a clear choice.

"Lighting is certainly one of those things you can justify," says Lum Lee, manager energy/utilities at Xerox Corp. in Webster, NY, where he has nearly completed upgrading the lighting system at the company's 7-million-square-foot site. "We upgraded to T-8s and electronic ballasts, and we put in occupancy sensors," says Lee.

Timing and financing were right for Lee when he started the Xerox program more than 10 years ago. For many facilities managers looking for the right time to upgrade, lighting systems often give definite clues.

Power density and light level are two measurable bases for identifying lighting system improvements, says John Fetters, president at Effective Lighting Solutions, Columbus, OH, citing General Services Administration (GSA) guidelines as an example. The GSA requirement for new or upgraded lighting systems is 1.1 watts per square foot (w/SF) for office lighting, Fetters explains. "If the power density of an office was 2.0 w/SF or higher, as many of the older systems are, then there is a potential savings of nearly 1.0 w/SF," says Fetters.

Illuminance can be measured in lighting audits and compared with industry standards or recommendations. "Light levels should be appropriate for current tasks," says Fetters. "When light levels are too high, energy is wasted and lighting quality is reduced. Too low, and safety and liability issues start to come into play."

Once it has been determined that a retrofit is needed, facilities professionals must decide where to start. "You need to look for areas where you can achieve similar light levels at significant energy reductions," says Phil Sanders, commercial lighting application specialist at GE Lighting, Warrenville, OH.

When operating a lighting system, notes Sanders, there are occasional lamp and ballast costs, and monthly energy costs. "The biggest area you want to go after is your energy," he says. If a system is 10 to 15 years old and ballasts are frequently failing, a T-8 lamp or electronic ballast will deliver the greatest efficiencies.

While focusing on efficiencies, Fetters warns against neglecting lighting quality. "Those who believe that lighting is a 'no-brainer' usually end up with poor lighting quality that affects worker productivity and ends up costing a company a lot more than it saves on energy," says Fetters.

When performing the upgrade, consider applications and take into account light depreciation of lamp output over time. "If the illuminance is right when the facility is upgraded or relighted, it will be wrong as lamp lumen depreciation and the dirt factor start to kick in," Fetters says.

Work areas may also seem too bright. "This usually happens when the higher surface brightness and the higher color rendering index (CRI) are not taken into consideration," says Fetters.

Identifying areas where savings can be achieved, as well as providing the appropriate lighting, can produce 35- to 50-percent savings, depending on existing lighting technology and required light levels, says Fetters.

Financing for lighting upgrades can vary from performance contracting to budgeting. While in the past, utility rebates provided incentives, they are rare today as the electric utility industry becomes deregulated. Oftentimes savings from the first portion of a phased upgrade can help pay for the project. The key, says Steven Goldmacher, director of communications at Philips Lighting, Edison, NJ, is that savings are ongoing. "[The goal] is not just saving for the three months; it is constant savings," he says.

Ineffective Lighting

* Lights on - nobody home.

* Lights on with daylight present.

* Lights over ceiling-high shelves or partitions.

* Incorrect light levels.

* Lack of maintenance.

* Directional lighting. What is it lighting? Is direction appropriate?


Lighting Efficiency Relationships

Efficiency, Unit Power Density (UPD) (w/SF), and Illuminance (FC) related

FC = Efficiency x UPD

lumens/SF = lumens/watt x watts/SF

Example: 50FC = 25 x 2w/SF

Doubling efficiency, reduces UPD by half, for same FC


Energy Effective Lighting

Selecting and applying efficient, quality equipment can help achieve higher lighting efficiency and higher lumens per watt (LPW), lower UPD (w/SF). It can also improve quality of visual environment and correct light level, low glare, better color (CRI), and lower flicker.


Elaine Watkins-Miller ( is an associate editor of Buildings magazine.
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Title Annotation:effective lighting techniques
Author:Watkins-Miller, Elaine
Date:Nov 1, 1997
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