LED Street Name Sign Lighting

Light-Emitting Diode (LED) technology has become the new indoor and outdoor general lighting standard. In the last few years, LED lighting has started to replace other lighting technologies. For example, due to their lower power consumption and design flexibility, LED lighting is now being used in place of High-Intensity Discharge (HID), incandescent, and fluorescent in applications such as decorative lighting and illuminated signage. Several cities and counties across the country have started to replace, or consider replacing, lamps that internally illuminate street name signs with LED lighting retrofit kits. The main motivation for replacing these lamps, which in most cases are fluorescent tubular lamps such as T8s and T12s, is to reduce energy consumption and the cost to operate street name signs. The energy savings can be substantial, especially with single-sided sign LED replacement kits that use LEDs only in the direction of their illuminated sign panels. These can help reduce energy waste, as opposed to fluorescent lamps, which project light in all directions. This goal of this project was to evaluate the energy consumption and performance of LED replacement kits for Internally-Illuminated Street Name Signs (IISNS), in an effort to better understand potential energy savings compared to traditional fluorescent tubular lamps. The approach was to measure the signs’ total energy consumption before and after retrofit, including all internal lamps and their required ballasts or drivers. We also recorded luminance values for the front of the sign before and after retrofit, to compare illumination performance. The evaluation was conducted in a laboratory environment, where ambient conditions, such as temperature and illumination, were maintained at constant levels. This study demonstrated that LED retrofit kits can in fact provide substantial energy savings to cities and jurisdictions operating illuminated street name signs. As seen in Table ES1, energy savings can be as much as 70% from the existing illuminating technology by assuming a 12-hour daily operation 365 days a year. In terms of demand reduction, our study measured as much as 70 watts (W) per sign by comparing the retrofit kit with the lowest power draw to the fluorescent baseline with the highest power draw. Several types of LED retrofit kit were evaluated and compared to two similar fluorescent baseline lamps. The values seen in Table ES1 represent the best energy savings and demand reduction scenario among the different types of lamps evaluated for a six-foot-long street name sign with double panels (front and back), originally illuminated by two six-foot T12 fluorescent tubular lamps. This configuration is among one of the most common in Southern California, but there are various sign configurations used by different cities and local jurisdictions. Some cities may use signs with only one side containing a message, signs shorter or longer than six feet, and signs illuminated by only one or more than two fluorescent lamps. The variety of sign configurations used by different cities and jurisdictions may represent an incentive level design challenge for utilities, since it makes it difficult to determine potential energy savings and demand reduction. Specifiers should carefully select the appropriate LED retrofit kit, to ensure it provides equivalent levels of performance to the baseline technology, and to ensure it meets any applicable state and federal requirements for sign illumination.