King David Kalakaua loved the then-new technology of electricity: He celebrated his birthday in 1886 by flipping the switch on a steam engine that powered incandescent lamps in Iolani Palace, five years before the White House updated from gas lamps.

Less than two years later, downtown Honolulu streets were brightened by electric lights.

For more than a century after Kalakaua’s reign, the palace’s light fixtures remained mostly unchanged.

Last month, the organization that cares for the palace completed a significant modernization of the building’s lighting, replacing 1,000 outdated incandescent bulbs with energy-efficient light-emitting diode lights that produce brighter light at a lower cost.

Because LEDs are free of harmful ultraviolet rays, the new lamps also protect photosensitive palace artifacts.

“There were a lot of shadows in the palace (before the change). It was much darker,” said Kippen de Alba Chu, executive director of The Friends of Iolani Palace. “And so what we would have to do is open the shutters to let in more daylight.

“When LEDs came out, we knew they wouldn’t harm (the artifacts) and we knew about the energy savings. But the bulbs that were coming out early on were bright white and ugly. Expensive, too. So we just had to wait for the technology to catch up.”

About three years ago, the palace commissioned an assessment of different LEDs to determine potential energy savings and aesthetics in keeping with the historic building. The palace’s curatorial department weighed in throughout the process, letting executives know when prototypes didn’t make the palace “look period enough” for them, de Alba Chu said.

After evaluating about a half-dozen potential replacements, the organization decided on a 4.5-watt LED bulb designed by Philips with an estimated energy cost of 54 cents per bulb per year. It was determined the soft white light the bulbs produce would most accurately portray the palace as it would have appeared during the monarchy.

In the palace’s throne room, for example, the new bulbs have made it much easier to view historical gowns on display, and now guests can pick out details in the ceiling moldings.

“Before, it was just white,” said de Alba Chu with a chuckle. “And down in the basement, heat from the spotlights was a factor before. It would actually get a little uncomfortable down there. Now, it’s actually much colder and our air-conditioning system doesn’t have to work as hard.” (LEDs produce less heat than incandescent bulbs.)

The retrofit included installation of an LED spotlight atop the palace roof to illuminate the Hawaiian flag that flies there; the next step, de Alba Chu said, would be to upgrade the roof.

Asked if this might include the addition of cost-saving solar panels, he said “we would love to do that. I don’t know if we’d get approval from the state Historic Preservation (Division) but it does keep in line with the king’s thinking.”

According to estimates, switching to LED bulbs has resulted in an immediate monthly savings of about $1,200, or approximately 7.8 percent of the palace’s monthly energy costs. The project’s total cost was almost $87,000, paid for with a grant from the state Legislature. The palace also received a $13,000 rebate from Hawai‘i Energy, the ratepayer-funded conservation and efficiency program administered by Leidos Engineering LLC under contract with the Hawaii Public Utilities Commission.

Every bulb in the palace’s public areas and administrative offices was replaced, but perhaps most breathtaking is the new brilliance of the palace’s facade by night.