Tesla’s new Solar Roof tiles are the hot topic of conversation right now. At the official reveal event, Elon Musk asked rhetorically, “So, why would you buy anything else?” In a new analysis, Consumer Reports (CR) tries to answer that question.
In the absence of pricing information from Tesla, Consumer Reports decided to make some assumptions of its own. People may quibble with them, but they at least establish a baseline that can be used to begin the discussion.
CR reached out to some knowledgeable roofing sources such as the Slate Roofing Contractors Association, the Tile Roofing Institute, and the folks behind the Remodeling 2016 Cost vs. Value Report. Assuming a typical roof size in the US of 3,000 square feet, it determined the average cost of a clay tile roof is $16,000, an asphalt shingle roof is $20,000 and a slate roof is $45,000.
CR then assumed the average annual utility bill for that typical home is $2,000. Multiplying that by the 30 year life span Tesla says customers can expect from their Solar Roof, that comes out to $60,000. Consumer Reports then backed out the $6,500 assumed cost of installing a Tesla Powerwall 2 from the projected cost of electricity and declared that a Tesla glass tile roof would have to cost no more than $73,500 in order to compete successfully with a normal asphalt shingle roof.
Note that in these calculations, the customer is expected to pay for 30 years of electricity up front. CR makes no adjustment for what the costs of financing that amount immediately might amount to over that same 30 year period. The analysis also does not factor in the location of the home, the angle of the roof, or its orientation toward the sun. Clearly, a roof in southern California will generate more electricity over its useful life than a roof in the northeast.
The team at CR also assume the combination of a solar roof and a Powerwall system will supply all of a home’s energy needs without the need to draw (and pay for) additional power from the grid. Finally, no allowance is made for the monthly fees many utility companies assess to homeowners who have residential solar systems. The industry position is that rooftop solar places an undue burden on the utility grid and forces the bills of other customers to increase.
Elon said last Friday the Tesla Solar Roof tiles will “look better than a normal roof, generate electricity, last longer, have better insulation, and actually have an installed cost that is less than a normal roof plus the cost of electricity.”
He is absolutely right about the aesthetics.” People like the idea of being energy efficient, but solar panels can be an eyesore,” says Giovanni Bozzolo, a partner at Roof4Less roofing in Seattle, Wash. “To be able to combine the energy savings with aesthetics would be a very big thing in the industry. But the pricing has to be right.”
So, will the pricing be right? After Consumer Reports checked all its sources, made all its assumptions, and crunched all its numbers, it said in order to be competitive, a Tuscan tile roof needs to cost less than $69,500 ($2,300 per 100 square foot). A smooth or textured tile roof needs to cost less than $73,500 ($2,450 per 100 square feet). A slate tile roof needs to cost less than $98,500 ($3,300 per 100 square feet).
Two important factors we don’t know are the cost of installation for a Solar Roof or the skill level installers will need. “Roofers aren’t electricians and vice versa, so I’m most interested in seeing how the costs of labor affect the end price to consumers,” says Vikram Aggarwal, CEO of EnergySage, an online marketplace of solar installers.
Elon Musk is right about one thing. The Solar Roof products we saw at Universal Studios last week are drop dead gorgeous. Any home owner would love to have one. The question is, will they be a luxury item, like a Tesla Model S, or affordable to a broad range of homeowners, like a Model 3? The answer is, no one knows. Asked for comment, a Tesla spokesperson told Consumer Reports, “We haven’t released details on pricing.”