Tesla's Solar Roof

Regina Nguyen
November 8, 2017

Submitted as coursework for PH240, Stanford University, Fall 2017


Fig. 1: Tesla Solar Roof tiles. (Source: Wikimedia Commons)

Though solar energy is touted as one of the most exciting, novel renewable energy sources, the fact remains that solar energy only accounts for 1.3% of global power generation. Problems such as the intermittence of the power supply and high costs are preventing solar energy from being a viable energy source for the masses. However, it did experience a 29.6% growth in 2016, and Elon Musk is looking to further boost this number and its usage with Tesla's Solar Roof. [1]

The Product

Sunlight provides the surface of the earth with much radiation. Working with Solar City, which it acquired in 2016, Tesla is hoping to harness this energy with its Solar Roof (Fig. 1). The main aim of the product is to be both cost- effective and aesthetically attractive; "Power your Home with Beautiful Solar" is the tagline prominently displayed on the product site. Currently, Tesla offers four tile types, from "textured" to "Tuscan," with the ability to customize how much energy is produced by mixing solar and nonsolar tiles on your roof. [2] The Solar Roof can be integrated with the Powerwall home battery, another Tesla product, to avoid an intermittence problem and guarantee energy during emergencies like power outages.

One of the product's major selling points is its durability. Since the solar cells are built inside tempered glass, the tiles are "three times stronger" than the roofing standard. Tesla boldly offers an "infinite tile warranty," also displayed in large font on the current website above animations of Tesla Solar Glass withstanding the impact of 100mph hail next to "traditional roof tiles" shattering. It is important to note, however, the lifetime warranty they offer now is only for the tiles themselves, and there is only a 30 power and weatherization warranty. [3]

Evaluating The Viability

The Solar Roof is a solution to elegantly integrate solar power with your home, something that bulky mounted solar panels cannot provide, but this advantage is insignificant if high expenses and negligible growths in efficiency are concerns, which they still are. Tesla has said that the tiles are $21.85 per square foot for the typical homeowner, and customers are also required to plunk down $1000 for the deposit. [3] Though not required but strongly recommended, the additional Powerwall installation costs about $7000 and is the only external battery that the Solar Roof can integrate with. There is an online cost calculator, but it includes a 30% Solar Investment Tax Credit and "deducts the upfront costs of the roof and the Powerwall battery from the cost of what you'd otherwise spend on energy over 30 years." [3] Tesla defends its high upfront costs with the product's long-term benefits and energy savings. An analysis by Consumer Reports proposes that the Solar Roof could save about $14,000 and $42,000 on their hypothetical houses in New York and California, respectively, but could result in a net cost of $13,000 on a house in Texas. In short, the savings will vary greatly depending on location, especially since the Solar Roof would make more sense in sunny places like California where the heat is not so overbearing that there is a huge burden on energy usage because of air conditioning. In addition to figuring out how to finance the upfront costs and looking at how much sun your home receives, another consideration according to Consumer Reports is how long you plan on owning your home, since your savings depend largely on how long you stay in that house.


While an exciting addition to Tesla's product lineup, the Solar Roof seems to provide only longterm benefit to those who can afford its high upfront costs, live and plan to stay in a house that receives much sunlight, and value appearance enough to want to buy this over normal solar panels. Musk is aware that at its current state, the Solar Roof is not a logical purchase for every homeowner, but there are apparently enough people whom the roof would be a good purchase for that the product has sold out until early 2018. [2,3] Until Tesla can expand outside of this niche market, though, it doesn't look like the masses will be enjoying the benefits of the Solar Roof anytime soon.

© Regina Nguyen. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] "Renewable Energy," in BP Statistical Review of World Energy 2017, British Petroleum, June 2017, p. A6.

[2] L. Hansen, "Tesla Taking Reservations For Solar Roofs," San Jose Mercury News, 10 May 17.

[3] P. Hope, "Doing the Math on Tesla's Solar Roof (Again)," Consumer Reports, 4 Aug 17.