Gaining energy efficiency through better lighting solutions

Efficient lighting provides a significant opportunity to reduce operating costs, improve occupant performance and reduce greenhouse gases that contribute to global warming. Utilizing energy efficient lighting, you can reduce lighting power density (LPD) by a minimum of 25 to 35% below ASHRAE 90.1-2004 guidelines while still meeting the New York City-based Illuminating Engineering Society of North America's lighting-design standards. By adhering to the LPD table which defines lighting power densities allowed in ASHRAE guidelines, it is still possible to use lower lighting power densities to achieve excellent visual quality. Interior finishes, texture, and color greatly affect visual quality, distribution of light and lighting performance. Higher surface reflectance on ceilings and walls increases lighting levels by reflecting light from available light sources. Glare from specular surfaces (mirrors, glass, etc.) will reduce visual quality and occupant comfort. To achieve recommended LPD reductions, CFL, high-performance T8 lamps with electronic ballasts and LED sources can be considered for general lighting. High-performance T8 lamps are defined as having a lamp efficacy of 90-plus nominal lumens per watt based on "mean lumens." Maintained; LEDs deliver a static level of lumens as there is no loss of light till the 70-80% of rated life when light output can decrease to 50% prior to complete failure. When selecting an energy savings solution, you should be careful to consider the lamp's color rendering index (CRI). The CRI is a scale measurement identifying a lamp's ability to adequately reveal color characteristics. Depending on the facility, the CRI can vary. For example, lamps specified for the ambient and accent lighting of retail merchandise should have a CRI of 80 or greater to allow consumers to effectively examine the color component of a product. Electronic fluorescent ballasts and LEDs should be used in all new and retrofit projects to reduce energy consumption and increase savings; dimming ballasts or LEDs dimming interfaces (0-10v dimming) can be easily integrated for simple wallbox switch replacements or more complex systems. In addition, occupancy sensors provide incremental energy savings. Rebate programs typically require the products being installed to comply with performance guidelines and minimum warranty periods to assure a level of quality is maintained. Be cognizant when hiring an energy efficiency expert as many products in the marketplace do not actually adhere to performance and quality standards. Steven Katz is the president of Lumescent, LLC (program partners for NYSERDA and a Green Team member for Con Edison), New York, N.Y.