City of Winslow Filtered LED Street Light Replacement Project; Dark Skies, Low Maintenance, and Energy Efficiency

What’s the Difference? 250 Watt HPS92 Watt Filtered LED

Background Winslow has a variety of street light types, mostly 250W High Pressure Sodium (HPS) and 100W Metal Halide lamps. Maintenance costs are moderate to high, depending on failure rates. In 2014, APS requested an increase in the Street Light Maintenance Contract for HPS lights of about 35%, so we decided we could do most of the work with City Crews. We reinvested the $20,000/yr. we would have spent for the contract on a used bucket truck. We were also spending ~$14k/yr. replacing 22 Metal Halide lamps by using a contractor who came in from Flagstaff. The failure rate was extremely high. Contract electricians and APS are still required to perform some street light maintenance other than the replacement of lamps, but this cost is minimal and infrequent. Satellite imagery of northern Arizona shows that Winslow’s light footprint is nearly as large as Flagstaff’s, with 1/7 of the population.

Background The International Dark Skies Conference was held in Flagstaff in 2014, and it was there that we met Dr. Bob Adams, a participant in the conference, who developed a filtered LED lamp meeting dark sky standards. His lamps were being tested in Flagstaff where we could see them. We invited him to Winslow to retrofit the 22 Metal Halide lamps on West 3 rd Street with Filtered LED lamps. This required a fabricated bracket to fit our custom street lights. The result is a reduction of $14k/yr. in maintenance costs because there have been ZERO failures in these fixtures. Metal Halide lamps are rated at 100 watts, almost the same as the 92 watts consumed by the LED lamps. The cost reduction is in maintenance costs indicated above. The success of this experiment convinced the City staff to move forward with the replacement of ALL of Winslow’s street lights with Filtered LED’s, and we have replaced over 100 of our 533 street lights in the last year as lights fail or when we do a capital improvement project on one of our streets.

Dark Sky Friendly Our LED lamp is fully shielded, and the filter removes the “blue light” from the color spectrum that plagues unfiltered LED light. Our light has a color temperature of 2,400k. The filter is designed with optics to direct the light to the street instead of scattering the light in all directions.

Dark Sky Friendly What is the significance of Blue Light? Considerably more glare Harsh light can be eye-straining Optometrists now sell eye glass coatings to filter out Blue Light Can impact sleep patterns in humans and animals Blue light increases light pollution

Comparison 250W HPS 250 Watts of power $4,700/mo. 16,000 Lumens $250 initial cost 1-2 yr anticipated life Not Dark Sky Friendly 92W Filtered LED 92 Watts of power $1,750/Mo. 9,000 Lumens $450 initial cost 10 yr anticipated life Dark Sky friendly 63% Reduction “ 44% Reduction 80% Increase 500% Increase The filtered LED lowers power consumption and virtually eliminates maintenance!

If we want to see this…

…not this…

we have to think like this.

Thank You Steve Pauken, City Manager City of Winslow 21 Williamson Ave. Winslow, AZ Dr. Bob Adams C&W Energy Solutions Paradise Valley, AZ