The reason that solar roofs aren't common is that they're more expensive than rooftop solar. As I understand it, Tesla/SolarCity's argument isn't that they're cheaper than normal solar, it's that they're the same cost as normal re-roofing once you take into account the income from the solar. From the ArsTechnica article: 'In a private conversation with journalists after the announcement, Musk declined to state a price for the roof or a price-per-square foot. He did admit "it's not gonna make sense for somebody to replace a brand new roof with a solar roof." But if your roof needs replacing anyway, he said, the cost/benefit could make sense for many families.'
More specifically, since SolarCity's business model is that they own the solar panels and you're committed to buying electricity produced by them for their lifespan, his argument is that it costs no more than conventional re-roofing + conventional electricity. There is of course the slight downside of you no longer owning the roof over your head, and having to commit to electricity purchases for the next decade or so.
More specifically, since SolarCity's business model is that they own the solar panels and you're committed to buying electricity produced by them for their lifespan, his argument is that it costs no more than conventional re-roofing + conventional electricity. There is of course the slight downside of you no longer owning the roof over your head, and having to commit to electricity purchases for the next decade or so.