Courtesy TED Conference/Flickr

After much hype over its so-called solar shingles, Tesla officially began taking orders in April, CEO Elon Musk announced on Twitter. Installations will begin in mid 2017, according to the company’s website. But the roofing industry isn’t so sure.

With the launch of its new product, Tesla (through SolarCity, which Musk acquired in November) is following a typical rollout model it’s used for other product launches such as the Tesla Model 3, said John Schehl, executive director of NRCA’s Roof Integrated Solar Energy Program. With that electric car, Tesla showed off a prototype and began taking pre-orders with a promise of building it in 2018. It’s already received 400,000 pre-orders.

But unlike taking a prototype of a car into production, solar shingles must be installed, not simply manufactured at an assembly plant. And as of yet, no one really knows what installation of the new solar shingle looks like, Schehl said.

“They haven’t said a word on how their product works,” he said. “Their business model is to take orders, get the business going and then we’ll figure it out later. So they’re bringing this product to market and taking orders and still there’s this big secret: how does this product work?”

He’s not alone in asking those questions. “I’m very skeptical,” said Aaron Nitzkin CEO of Solar Roof Dynamics, a company that helps roofers gets into solar installation. “Who’s going to install it? Is Elon Musk going to have Tesla installing roofs? How is that going to play out? I have absolutely no idea.”

When word first came about the solar shingle in October, NRCA took the extraordinary step of reaching out to Tesla and offering installation guidance, Schehl said. Tesla’s response? Silence — except the company did join NRCA.

Unlike other solar products that work with a existing shingles, the Tesla solar shingle is meant to replace conventional shingles. Musk has even said that the new product will actually cost less to manufacture and install than a traditional roof, even before solar savings. “Electricity is just a bonus,” Musk famously said. However, the SolarCity website says the shingle product “costs less than an equivalent roof when combined with projected utility bill savings.”

Either way, installing roofing shingles involves more than just shingles, Schehl contended. Shingling a roof means dealing with peaks, valleys, hips and slopes and properly flashing those areas to prevent leaks. Schehl said it’s unclear how the Tesla solar shingle product will handle that aspect of roofing.

Add to that the technical challenges a solar shingle represents and it becomes even harder to imagine how the roofs would be installed. For example, Nitzkin said a fully solar roof requires each solar shingle to have two electrical connections. And each of those shingles must be connected to the rest of the shingles. “When it debuted, there was no sign of anything electrical. Just a shingle,” he said. “So is it going to be what he showed at the media event? No. It would be way too expensive. He showed what I believe to be a nonfunctioning product when they did the media splash.”

In fact, Nitzkin said he saw the solar shingle announcement more as a way to convince SolarCity to sell than an actual product launch. “It was very clearly done to paint a vision and get shareholders excited,” he said.

That vision is laid out on SolarCity’s slick website, which dissects the Tesla solar shingle into its parts: a tempered glass tile that houses a colored louvered film and a solar cell. The tiles comes in styles ranging from Tuscan, smooth, textured and slate to accommodate different housing aesthetics, the website says. Tuscan and slate styles are said to be as much as 20 times more expensive than conventional asphalt shingles. Tesla’s solar roof can be paired with its $5,500 Powerwall product, which is designed to provide power at night and in the case of power outages, according to the website.

While all of that sounds impressive, Nitzkin said the complexities of roofing make the solar shingle one of the most difficult products Tesla has ever handled. But though he remains skeptical, Nitzkin also recognizes that Tesla has proved the skeptics wrong before. “Part of me says it sounds kind of fictitious,” he said. “But the other part of me tries not to underestimate someone like Elon Musk.”

Even if Musk produces the actual product, Nitzkin said he’ll eventually have to work with roofers to install it due to labor shortages. “My guess is that SolarCity will use its own labor,” he said. “But at some point they’ll have to figure out how to leverage the infrastructure that’s already here.”