Last summer, we blogged about a parking garage LED retrofit in Raleigh, North Carolina, the first city to participate in Cree’s LED City program in 2007. Raleigh replaced 144 188-watt high pressure sodium fixtures in a local parking garage with 70-watt LED lamps. Also, many of the LED fixtures were equipped with a photocell sensor that turned the lights off for 12 hours during the daylight hours. After the retrofit, the city surveyed those who used the parking garage frequently, and both men and women said they felt safer in the garage, the quality of light was better, and it was cleaner and easier to maneuver through. At the time, electricity savings were totaling to $2,803 annually, and maintenance savings were totaling to $3,325 annually.

Four years later, we can say that the results of replacing those high pressure sodium lamps with LEDs are positive. If you totaled the two amounts above, annual electricity and maintenance savings equaled to $6,128, but actually, the new lighting is saving the city more than $13,000 per year, doubling the first case study’s savings results! Another important area the city was watching was light degradation over time and operation lifespan. As of now, the city is expecting the lights turned on all day to last more than 50,000 hours, equaling 5.7 years. The lights equipped with power sensors are expected to last 11.4 years. So far, they have not had any problems with LEDs. Since this project, Raleigh has completed about 35 LED indoor and outdoor projects. The city has installed lighting in the mayor’s office and the local performing arts center. Outdoor projects include installations in parking garages, streets, parks, freeway underpasses, landscaping, and pedestrian bridges. These projects have saved Raleigh $225,000 annually!