Some San Franciscans think the city's new LED-powered streetlights aren't such a bright idea.

In June, city officials announced a major push to replace 12,500 outdated streetlights with brighter, more energy-efficient light-emitting diode fixtures, also known as LEDs. The lights are intended to increase visibility and curb electricity and maintenance costs.

But some people, blinded by the bright white glow of the new LED lights, can't get behind the city's new nighttime hue.

"They just replaced one of my streetlights in the Lower Haight and it lights up my living room like a floodlight," wrote Reddit user @Bronco4bay on a thread discussing the costs and benefits of the new lights.

Redditor @clampie agreed, writing, "Save the night. LED should be a warmer hue."

Most LED lights emit so-called "blue light," which has a shorter wavelength and produces a higher amount of energy than other, warmer-hue types of light.

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Some think brighter is better, especially when it comes to public safety.

"I'd rather have it brighter," said Rebecca Woo on Facebook. "Isn't that the point of streetlights?"

Though the LED streetlights may seem brighter, they are actually of the same brightness as their high-pressure sodium counterparts, according to PUC spokesperson Charles Sheehan, who admits the city has "gotten some feedback" since the major light rollout began.

Sheehan said the city measured "existing light levels" on streets and converted that figure into LED wattage to match the brightness already present on the street, but there's some fine print.

The LEDs may appear brighter, Sheehan said, because they don't experience lumen depreciation – in other words, they don't dim with time – like high-pressure sodium bulbs.

"People can notice that," Sheehan said, "especially if they are on a street that has older lights."

And because LEDs provide more uniform light distribution, they won't have glare or dim spots like their older counterparts.

The LED debate is not just a matter of aesthetics; scientists say the LEDs affect humans differently than the high-pressure sodium bulbs in San Francisco's traditional streetlights.

"Despite the energy efficiency benefits, some LED lights are harmful when used as street lighting," said American Medical Association (AMA) Board Member Maya A. Babu in a statement of recommendations the organization developed to help cities reduce harm from high-intensity streetlights.

LED lights emit large amounts of blue light, the statement explained, which can create a worse nighttime glare than traditional lighting and thus endanger drivers and pedestrians. AMA also cited LED streetlights as adversely suppressing the body's creation of melatonin at night.

"It is estimated that white LED lamps have five times greater impact on circadian sleep rhythms than conventional street lamps," the statement said.

It continued, "Recent large surveys found that brighter residential nighttime lighting is associated with reduced sleep times, dissatisfaction with sleep quality, excessive sleepiness, impaired daytime functioning and obesity."

All of San Francisco's streetlights are set to a color temperature of 3,000 Kelvins (a warm white hue), which is in compliance with the AMA's recommendations, Sheehan said. Residents particularly perturbed by their new streetlights' brightness can call 311 to have the city install a light shield, if appropriate in that location. A light shield is an attachment that helps direct light downward and away from residences.

While Sheehan admits the LEDs provide a different visceral experience than that of high-pressure sodium bulbs, he thinks residents will get used to it. Like all major civic changes, it may take some time for people's eyes to adjust to the light.

PUC has a handy map showing the locations of converted streetlights.

Dominic Fracassa, a San Francisco Chronicle staff writer, contributed to this report.

Michelle Robertson is an SFGATE staff writer. Email her at mrobertson@sfchronicle.com or find her on Twitter at @mrobertsonsf.



