Inteva, which was spun off from Delphi Automotive in 2008, markets a line of sunroofs that generated about $1 billion in sales in 2014 -- roughly a third of its total revenue.
The company expanded its presence in that segment when it acquired the body systems division of ArvinMeritor in 2011. That deal doubled Inteva's size and gave it a bigger presence in Europe and Asia. In an interview last month, Inteva CEO Lon Offenbacher said sales in that segment are growing 15 percent annually.
For vehicles that offer an optional panoramic sunroof, the "take rate" in Europe and North America is 30 to 40 percent, Offenbacher said. In China, the take rate rises close to 100 percent on some models. Chinese customers "will buy it over a radio," Offenbacher quipped. "It's incredible."
In years past, automakers often designed panoramic sunroofs for concept cars to make the interiors airy and luxurious. But they rarely made it into production because they were heavy and affected the roof's structural integrity.
About a decade ago, a couple of technical advances made panoramic roofs more practical. Engineers used lightweight materials such as aluminum and plastic to design lighter sunroof frames, and they used high-strength steel to reinforce the A- and B-pillars.
Automakers began introducing large sunroofs in the early 2000s, and now they can be found on models such as the Hyundai Veloster, Scion tC and Mini Cooper.
Prices vary widely, but panoramic sunroofs can be quite affordable. For example, the Mini Cooper hardtop offers it as a $1,000 option, while it's standard on the Scion.