SACRAMENTO, Calif. — As entrepreneurs look for ways to capitalize on the national movement to cut energy use, an established Sacramento firm is succeeding with an old technology.

Rising prices for electricity and stricter building codes have driven up sales for skylight manufacturer Sunoptics after three decades of more moderate growth.

“We’ve been growing at approximately 40 percent a year since 2007, right in the middle of the biggest recession since the ’30s,” said Grant Grable, a company vice president.

Sunoptics has manufactured energy-efficient skylights at its Sacramento facility since 1978 and now includes Wal-Mart Inc. among its clients. The company’s design is simple, but it promises to significantly reduce energy costs for clients.

Last year, Sunoptics was acquired by Atlanta-based Acuity Brands, a publicly traded lighting and lighting-controls company with $1.8 billion in annual sales. Details of the sale were not disclosed.

With Acuity’s support, Sunoptics renovated 12,000 square feet of space in one of its warehouses into offices and a training center.

There are no electric lights on in the company’s newly renovated lobby during the day, but the room is full of light from Sunoptics products in the ceiling above.

“When you walk in and there’s light everywhere and no electricity being used, you’re suddenly going to get it,” said Jim Blomberg, the president of the company before the acquisition. “You’re going to go, ’Wow, that’s awesome.’ ”

Manufacturers typically add pigments to their skylights so they will spread sunlight throughout a room instead of throwing it in one spot on the floor and leaving the rest of the room dark.

“The pigments would scatter the light, but they would also reduce the amount of light that was transmitted,” said Jon McHugh, who consults with governments and utilities about energy efficiency.

Sunoptics uses finely dimpled acrylic sheets, like those used in fluorescent bulb casings, to disperse light into the room below. The skylights do not cast bright spots or shadows and are meant to replace electric lights entirely for eight to 10 hours a day.

“It’s like 4,000 little mirrors per square foot,” Grable said of the skylights. They are most effective in warehouses and in other large buildings with high ceilings. Sunoptics has provided skylights and lighting controls for about 4,000 Wal-Mart stores since 1993.

When it began producing skylights for Wal-Mart, Sunoptics had only 10,000 square feet of manufacturing space and one thermal forming machine, an oven for melting plastics to a mold. The added volume allowed the company to add manufacturing capacity, and to begin extruding its own plastic sheets from unprocessed acrylic pebbles instead of buying finished sheets from suppliers.

Vertical integration gave the company more control over the quality of its materials.

“That was a real game-changer,” said Blomberg. The company now employs about 100 people at its 124,000-square-foot facility.

Sunoptics was well-positioned to take advantage of an expanding interest in efficient building design.

The California Energy Commission included a requirement for skylights in certain buildings in the state’s building codes in 2005. In 2011, the federal Department of Energy announced that other states would have to do the same.

“There’s nothing like a government mandate to increase your market opportunity,” Grable said.

McHugh, the energy consultant, has calculated that if skylights such as those manufactured by Sunoptics were installed in every warehouse and big-box retailer in the United States, the country would reduce its power use by enough to shut down 10 typical power plants.

“I’m an energy engineer, and this is a no-brainer in many circumstances,” McHugh said. A nationwide retrofit would save the country $2.5 billion a year, enough to cover the initial costs in about five years, he said.

Even without the new regulations, economic conditions are forcing owners of buildings to find ways to save money.

“The environment that I have to sell to these days is not what it used to be,” said Tom Desimone, a business developer at Platinum Roofing in San Jose, Calif., who has been working with Sunoptics for 12 years. He said that many owners will finance improvements to their buildings by reducing future energy expenses.

“Sunoptics is far ahead of the curve and has been for years,” Desimone said. “Now everybody is trying to play catch-up.”