Tesla solar roof

Image source: Tesla

What's Special About Tesla's Solar Roof Tiles?

There are several factors that give us hope for Tesla's Solar Roof. First and foremost, we know that Elon Musk does nothing without thinking about curb appeal. Like his original electric vehicles, his shingles also have to live up to a very high standard of what we deem modern aesthetics. If they aren't good enough for Musk's home, they aren't good enough for consumers. As a result, the four solar shingles he's released are remarkably attractive from a curb appeal standpoint. They can be made to look like modern slate tiles or traditional shingles. He has added textures and colors to further distinguish his product from his predecessors'.

Tesla roof tiles

Image source: Tesla


The second factor that seems to be in Tesla's favor is the science. Not only has solar technology come a long way in the last few years, it has also become more affordable and more precise.

Rather than selling you a roof full of highly expensive solar tiles, Tesla has worked out a system for mixing solar-active and non-active tiles across your roof. The result is that any individual home can have 40-70% active solar tiles, which are expensive, while the remainder of the roof is covered in aesthetically equal non-active tiles. This creates a uniform look while allowing for a more fluid pricing structure. The fewer active tiles you have, the lower the cost of the installation. In the past, this was done by simply placing bolt-on solar tiles over your existing roof only in the areas where they would be most efficient and leaving the rest of your roof solar free, which was considered unattractive by many consumers.

Finally, Tesla has taken their Solar Roof one step further by creating a base standard for lifespan and durability. Previous solar shingles have been notably fragile and unable to withstand the varying weather conditions around the world. Tesla seems to have solved this problem with a tempered glass solution that makes these tiles nearly unbreakable. Furthermore, they have worked hard to ensure that the underlying photovoltaic cells will not age prematurely, leaving homeowners with inefficient panels that can't produce enough power.

What solar cells are used in the Tesla solar roof tiles?

Tesla has wisely partnered with one of the best makers of solar cells in the world, Panasonic.

The Panasonic HIT hetro junction cells generate solar power of both the top and bottom surface of the cell. In 2014 they claimed a world record 25.6% cell efficiency in a single cell in a laboratory and in 2017 they announced a production module with an average module efficiency of 22.1% which is similar to the most efficient Sunpower modules.

In short I think Tesla have made a wise decision to partner with Panasonic for their solar roof product because they are one of the most stable and financially successful electronics manufacturers in the world.

But what about the economics of the Tesla solar roof tiles. Americans love Elon but do they love their bank balance more?

How Much Does the Tesla Solar Roof Cost?

The only real hitch in this plan is the actual price of the solar shingles themselves. Where a typical roof replacement costs between $3-6/sq ft across much of the nation, a Solar Roof with a mix of active and non-active tiles is closer to $22/sq ft.

For a 3000 sq/ft home this is a cost of $66,000 v's a cost of 12,000-18,000 for a typical new roof using metal, concrete tile or ordinary roof shingles.

Can you claim the 30% solar tax credit on the Tesla solar roof tiles?

You can claim the federal solar tax credit on the solar roof tiles that actively generate solar electricity. However, you cannot claim the solar tax credit on the non-active roof tiles that you purchase to look like the active solar tiles and to give you the uniform curb appeal so important to the marketing of the Tesla product.

How does the cost of the Tesla roof tiles compare to conventional solar panels?

If you weren't in the market for a new roof, but were looking at solar panels alone, the national average for a 5kw system is about $16,000. When you deduct the value of the 30% solar tax credit this leaves a cost of 11,200

By contrast, a new Solar Roof could be significantly higher than that by the time you include the active and inactive roof tiles necessary to cover your whole roof. In the example above we were looking at a 3000 sq/ft roof and so the cost was $66,000. However, this is likely to be less if we only wanted a 5kw solar system and in fact most of the roof tiles would be the cheaper inactive roof tiles.

Although it is necessary to guess a bit because at the time of writing (March 2018) Tesla has not released pricing for the active and non-active roof tiles in the system, the cost is likely to be more like $50,000 with the 30% solar tax credit on around 10% of these tiles, being the electricity producing tiles only.

The cost would be even more if the solar roof was paired with the Tesla energy storage product, the Powerwall 2 which costs around 8,200 installed for a solar battery with 14 kwh's of storage capacity.

How big are the active Tesla solar roof tiles?

The solar roof tiles are each 184 mm x 365 mm

Naturally, the cost of the Solar Roof is not meant to be compared to a standard roof. The equation they propose factors in the value of energy saved over the course of the roof's life.

How long is the warranty on the Tesla solar roof tiles?

Tesla is now offering an infinite warranty on its solar roof tiles. Given traditional shingle roofs only last 20-25 years this is a strong selling point but is it a realistic warranty.

Although I regard Elon Musk as a visionary who will have an amazingly positive impact on the world even if his company fails economically, at times it seems like they make long term warranty claims that are irresponsible. It all seems to be about knocking over roadblocks and sales objections rather than a sensible economic analysis. I am also skeptical and concerned about the 10 year warranty on the Powerwall. (but fingers crossed because I'm going to buy one anyway).

If a solar roof will last 50 years, (as the company promises given 50 years is less than infinity years), which is twice as long as a traditional shingle roof it's possible that the investment in a solar roof, whilst 400% more expensive than either a traditional roof or a traditional solar system of the same size, may start to look like a reasonable investment.

Will the very strength of the solar roof be its downfall?

The selling point for the solar roof is that it makes solar attractive and aesthetically pleasing.

However, this promise means that it has to make all the tiles look the same and this means consumers are paying a huge premium for the non-active solar roof tiles that do not generate electricity. It may be

The average house only needs 400-500 sq/ft of solar panels to cover its average power usage of around 800 kwh per month. Given a standard single family dwelling roof might be more like 3,000 to 4,000 sq/ft this is a lot of premium to be paying for expensive non-solar roof tiles that look like your solar roof tiles.

Perhaps the secret to the success of the solar roof might be Tesla allowing other roof tile manufacturers to manufacture the non solar active tiles to increase competition and reduce cost.

What Does the Future Hold for Tesla Solar Roof tiles?

Only time will tell what is destined for the Tesla solar roof brand. Ultimately, it will come down to whether or not Tesla can roll out the product as promised, and how long homeowners are willing to wait, and how much can it change the way solar systems are perceived from being a clunky piece of engineering to an aspirational luxury brand

Fortunately, Musk has a huge fan base that is willing to follow him to the ends of the Earth, literally. They are used to product delays and challenges, but most of them still stand by him. This bodes well for the celebrity genius and for Solar Roof as a whole.

Musk is seeking to make the solar roof a luxury architectural inclusion. It is not uncommon for those building luxury homes to spend this type of money on a fixture that they think will help define the styling of the building. However, this is quantum leap from the way solar systems have been seen as something offering functional benefit but with aesthetics that have to be endured rather than enjoyed.

All of this is to say that the future of Solar Roof cannot be decided today. For one thing, it has a lot more going for it than other low-key solar shingle options of the past. It has the backing of many big names, and the rollout is being led by engineers who are testing the products on their very own homes to prove its efficacy. While the cost of the solar shingles may be a stumbling block for the average person, Musk and Tesla together have proven that they can build a brand by catering to the wealthy first and then moving their way down into more affordable markets. It would not be surprising to see the Solar Roof continue to gain in efficiency and cost effectiveness, eventually reaching a level where it is widely accessible.