What is the lifespan of an LED street light?

The lifespan of an LED street light is typically measured by the "L70" metric—the number of hours it takes for the luminous flux to decline to 70% of its initial value. High-quality LED street lights can achieve an L70 lifespan of 50,000 to 100,000 hours, depending on the quality of the LED chips, the LED driver, the thermal management design, and the operating environment. In a typical mid-sized city, where street lights operate for 11 hours each night, 50,000 hours translates to approximately 12.4 years, while 100,000 hours equates to about 24.9 years. In practice, however, the LED driver often has a shorter lifespan than the LED chips themselves—typically ranging from 30,000 to 50,000 hours (about 8 to 12 years).

Consequently, after 8 to 10 years of operation, an LED street light may still emit light, but the driver might have failed, or the light output may have degraded significantly, necessitating the replacement of either the driver or the entire fixture. Some high-end products utilize long-life solid-state capacitors and redundant design architectures, allowing the driver to reach a lifespan of over 70,000 hours. Key factors affecting lifespan include junction temperature (reducing it by 10°C can double the lifespan), power grid stability (voltage surges can damage the driver), environmental corrosivity, and the integrity of waterproof seals.

To extend the operational lifespan, it is advisable to select reputable brands for both the LEDs and the drivers, keep heat sinks clean, install surge protection devices, and avoid running the lights at full power for extended periods in high-temperature environments (smart dimming strategies can be employed for this purpose). When procuring these units, one should request lifespan projection reports based on LM-80 and TM-21 standards, rather than relying solely on promotional claims.