No, Tesla's solar roof will not cost less than a "regular" roof
A few weeks ago, shortly after introducing his gorgeous new solar shingles, Elon Musk told a meeting:
It’s looking quite promising that a solar roof will actually cost less than a normal roof before you even take the value of electricity into account. So the basic proposition would be, 'Would you like a roof that looks better than a normal roof, last twice as long, cost less and by the way generates electricity?' Why would you get anything else?
Since then sites have run with titles like:
Electrek: Tesla’s solar roof to cost less than a regular roof – even before energy production, says Elon Musk
Huffpo: Tesla's Solar Roof Will Cost Less Than A Normal Roof, Elon Musk Says
Popular Mechanics: Elon Musk Says His Solar Shingles Will Cost Less than a Normal Roof.
The trouble with all of these headlines is that they never define “normal” and “regular.” Because once again, Musk is in a Silicon Valley bubble where people all drive Teslas and live in big houses with clay tile or slate roofs, neither of which are “normal” or “regular.”
In fact, according to roofing sites, well over 80 percent of roofs are asphalt shingles, with metal roofing in second place. (UPDATE: a reader informs us that cement tile roofs are quite common in California) The number of houses with what Elon Musk considers a “normal” roof is very small, and limited to the very rich. That’s because of the comparative costs; per roofing square (100 square feet)
Asphalt shingles, basic: $ 90
Steel Roof: $ 120
Concrete tile: $ 300 to $ 500
Clay tile: $ 800 to $ 1,000
Slate tile: $ 1,100 to $ 2,000
According to Musk as quoted in Electrek,
He said that the glass developed by Tesla for the solar roof tiles weigh “a third, a quarter and sometimes even a fifth” of other current concrete and ceramic roof solutions. Musk calculated that because of the weight and fragility of the current products, logistic costs and breakage are important parts of the total cost.
But that is not true of asphalt shingles, which are lighter, not fragile and easy to ship.
Now TreeHugger is no fan of asphalt shingles. They are, as I have noted before, the the cheapest and ugliest building enclosing material ever invented. But they are normal. What Elon Musk is selling is not normal or regular, but a comparable for a very high end niche product that is used for a tiny fraction of roofs on houses of very rich people, that costs between ten and twenty times the price of a normal, regular roof.
They are a normal and regular roof like a Tesla is normal and regular car.