If some streets and sidewalks south of Boston look different to you lately, there’s good reason: Those high-pressure sodium street lights that have long bathed both in a yellow tinge have been replaced with brighter, bluer, and more energy-efficient LEDs.
Municipalities statewide are pressing ahead with plans to make the switch, aided by more than $4.3 million in grants that Governor Charlie Baker’s administration announced in late September. Local grant recipients included Brockton, Cohasset, Foxborough, Hanover, Holbrook, Quincy, Rockland, and Weymouth.
Others — including Dedham, Easton, Randolph, Sharon, and Westwood — have already completed LED street light retrofit programs.
The grant of more than $38,000 to Cohasset won’t cover the costs of converting all of the town’s street lights. That tab is expected to be about $170,000, said Mary Jo Larson, who chairs the town’s Alternative Energy Committee.
But despite the hefty price tag, there’s a financial incentive for the town to make the change.
“Certainly there’s tremendous energy savings for us, as far as the electric bill,” Larson said. LEDs use less energy and need to be replaced far less often, she said.
But for some, those savings are offset by concerns about the brighter lights. In a post on its website, the International Dark-Sky Association said that while LED technology has the potential to reduce light pollution, “if it is done right,” there’s a real danger its lower costs will ultimately lead to a lot more lights.
Others have argued that the blue light emitted by some LED bulbs can have a negative impact on health. Last year, the American Medical Association warned that bright LEDs with high levels of blue light can disrupt melatonin production at night.
“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,” the group said in a statement.
And besides the medical concerns, some simply find LED lights irritating.
“Some people have a misconception about LEDs,’’ said Larson, “and their first impression . . . [is] that they’re entirely too bright, when really there are so many different variations.”
“None of the lights that we’re choosing are really very bright lights,” she said, adding that the town will probably pick one with a lower color temperature, measured on the Kelvin scale, that does not emit much blue light.
Cohasset residents will have a chance to weigh in before a final decision is made. In early January, officials put up a display with three different LED lights near the center of town, Larson said. The town is planning to offer tours, probably in February. Residents will then be able to express their opinions of the lights through an online survey, she said.
“It’s our way of informing the town about the options that are available and giving them a voice in terms of their preferences,” Larson said.
In Quincy, which received more than $350,000 in state aid, workers are finally replacing the city’s 6,500 lights after years of planning, said Chris Walker, a spokesman for Mayor Thomas Koch.
The city began considering the change in 2014, but it had to buy street lights from National Grid and get the plan approved by the City Council.
The total cost is about $3.5 million, Walker said. He estimated the project would pay for itself within six years.
While a few residents have complained about bright light entering their homes, Walker said, “particularly on our main thoroughfares, the response has been largely positive.”
“We see the quality of the light as a benefit — the cleaner, crisper light,” he said. “I’ve noticed the difference. You drive down a street now and you can see on one side where they’ve done it with the new lights, and with the old lights you can really tell the difference.”
Maintaining the lights should become easier, too, he said. In the past, the city had to work with National Grid and several middlemen just to replace a bulb, Walker said.
In Weymouth, the process is not as far along. Contractors recently completed an audit of all street lights, allowing officials to know which lights the town needs to buy from National Grid, said Bob O’Connor, Weymouth’s energy coordinator. The town is working out “a few discrepancies” from the audit but will eventually own all 3,700 lights and replace them with LEDs, O’Connor said.
The entire project is estimated to cost $1 million, but Weymouth received a grant of almost $250,000 from the state. The project will pay for itself in four years, O’Connor estimated.
“By itself that’s a huge savings,’’ O’Connor said. “Not only are you saving the taxpayers’ dollars, but we’re also saving energy. It’s a huge double-benefit there.”
Weymouth officials will probably solicit bids for fixtures that could be controlled remotely, O’Connor said, but he acknowledged the cost may be prohibitive and the city may not go that route, after all.
“It all comes down to the results of the bid anyway,’’ he said, “but we’re just trying to get up to speed on what technology is out there, what brands are reliable.”
Brockton, meanwhile, is already installing such fixtures as it sets up LED lights citywide. The so-called “smart controls,” said Mayor Bill Carpenter, will allow the city to dim and brighten the lights at will, saving energy.
“The potential for the smart controls is unlimited,” Carpenter said. “They essentially create a wireless network for us across our entire city.”
While Brockton officials have not determined what else the controls will be used for, Carpenter said the city is looking at technology that would monitor the sewer system and use the fixtures to send a signal if there are problems.
“Our vision is to become a 21st-century city, and be a smart city,” he said.
The total cost of the project, including the smart controls, is about $3.1 million, Carpenter said. But with grants from the state and expected rebates on energy savings from National Grid, the city should shell out less than $2 million.
“We’re getting safety, we’re conserving energy, we’re saving money,’’ he said. “It’s a win on several fronts.”