Why Tesla’s Solar Roof Is A Bargain, 53% Of The Price Of A Roof + Electricity — CleanTechnica Analysis
Were Elon Musk’s claims about the cost of Tesla’s solar roof true? Is Tesla’s solar roof tile system cheaper than buying roof and grid power?
When Elon Musk, CEO of Tesla, unveiled the company’s solar roof tile system in 2016, he boldly stated that it would cost less than buying a roof and electricity. Since then, we haven’t seen any data to support his claim.
I signed a contract with Tesla to install a new Tesla solar roof tile system and unwrapped the good and bad details from the contract into a series of articles. To start off, I’ll first compare the cost of the system to Elon’s claims to see if a Tesla solar roof tile system is actually cheaper than buying a roof and the energy the system generates over its lifetime.
A roof to rule them all
For an accurate comparison it is necessary to use an accurate baseline for the cost of electricity and the cost of a new roof. Installing a new roof can range from $ 10,000 to $ 50,000 depending on the material used. Composite shingle roofs and tile roofs are cheaper, but do not have the same durability as a Tesla solar roof made with hardened glass tiles. Tesla’s solar roof consists of: “Glass solar tiles are so durable that they are guaranteed for the life of your home or for infinity, whichever comes first.”
The only roofing product on the market that comes close to this bold proclamation is a metal roof with an expected lifespan of 50 years. This is an important comparison to understand because just looking at the Tesla solar roof as a cover for the house already sets it apart from most popular roofing products. It’s a high-end roof, even without the solar aspect. This is not a justification for a higher price, but the reality of buying a roof that will last a long time is simply the reality.
The Tesla solar roof is not your typical roof, and that is underscored by the fact that there are two different guarantees. The first is for solar production from the roof. The solar production from the solar roof has a guarantee of 25 years. This protects the buyer from sub-par solar cells, failing cells, or other factors that affect the generation of electricity from the system. Such a guarantee is standard throughout the solar industry. The second guarantee is for the physical roof structure. Since the Tesla solar roof is a building-integrated photovoltaic system (BIPV), it must serve as a physical roof for the house in addition to generating electricity. As a roof, the Tesla solar roof is guaranteed for infinity or the life of the house, whichever comes first.
To ensure accuracy, I received quotes for the job from 5 real local contractors in Southern California. This was not a hypothetical exercise as we needed a new roof and were actively pursuing both options to determine which would be a better fit for our family. The offers were made on the basis of the actually permissible architectural drawings of the roof with all associated folds and warts. After receiving all the quotes, I took the average price from all 5 contractors and used that as the base cost for a comparable roof installation. That came to $ 37,865.80 for a new metal roof.
Electricity under a different name
Musk and his team of energy engineers at Tesla weren’t just trying to build a better roof. They ultimately tried to build a solar product that would help the masses adopt solar because it was simpler, cheaper, higher quality, and better looking. It’s a big job in every way.
On the cost side of the equation, it’s easy to take the cost of electricity from the US Energy Information Administration (EIA) and extrapolate that price over 25 years. I used the most recent cost of residential electricity in California of 19.3 cents / kWh (March 2019) and extrapolated this with a conservative annual increase of 2%. For the sake of parity, I have rated the system based on the solar system’s production after the maximum deterioration noted by Tesla. The solar roof system should be generated during the 25-year guarantee period for solar production from the system Electricity valued at $ 73,436.14.
Dimensioning the solar roof
We don’t have a gas pipeline to our house, so everything in the house is powered by electricity. We also have two electric vehicles that get most of their electricity from our home. To offset this consumption as much as possible, we are installing the largest Tesla solar roof tile system that our roof can handle.
The system dimensioning on a Tesla solar roof is different to conventional solar systems, in which the number of solar modules used depends on the necessity and the roof capability. Since a Tesla solar roof must serve as its primary function as a physical function for the house, tiles must cover the entire surface. To size the system, Tesla created tiles that have solar cells and tiles that don’t – and they all look essentially the same. With smaller systems, Tesla simply uses fewer tiles that contain the actual solar cells.
The Tesla solar roof for our house has solar cells in every possible place. There are some areas around the roof edges and near the hips and joints with no cells, but every other surface is set up to generate electricity. The primary area of our roof faces south, which is ideal for solar production. However, in the configuration we used, the roof surfaces facing north, east and west are also used. While this maximizes our solar energy production, it results in a lower yield from the system compared to a system with all active tiles facing south.
Overall, Tesla was able to fit one 10.59 kW system In our roof, which is expected to produce 13,126 kWh in the first year of operation. This corresponds to the size of a system of 32 x 330 watt solar modules! The system I want to remind you of also serves as a roof for our home and was $ 70,375.23 before discounts and $ 58,603.04 after discounts. Compared to the cost of a metal roof, the Tesla solar roof was $ 20,737.24 more.
When we translate this data into Nerd-Speak, also known as an Excel spreadsheet, we can see that The cost of installing a metal roof and purchasing the equivalent of the electricity produced by the Tesla solar roof system would be $ 111,301.94while the Tesla solar roof is only $ 58,603.04. These are not hypothetical or mythical numbers, just a simple summary of spending in two different scenarios over 25 years. In other words, the Tesla solar roof accounts for 52.7% of the cost of installing a comparable roof and purchasing electricity from the utility.
What about a composite shingle roof?
It’s interesting to cost a Tesla solar roof compared to a metal roof, but that’s still a very expensive roof. Musk said at the company’s annual general meeting on June 11, 2019 that the solar roofing team was really pushing to get the ubiquitous composite shingle roofing themselves. According to the only estimate we’ve got of a composite shingle roof for our home for just $ 12,000, the solar roof system is still ahead of the game.
We can use the same $ 73,436.14 for the value of the electricity generated and $ 12,000.00 for the composite shingle roof for a total of $ 85,436.14. This includes the cost of electricity over the life of the system from the utility and the physical composite shingle roof. Compared to $ 58,603.04 for the solar roof, composite clapboard is already more expensive here in Southern California.
Even if I throw in the roof myself as free, the solar roof is cheaper than buying electricity from the utility here in California, saving nearly $ 15,000 over 25 years. It won’t make or break your retirement, but it’s impressive to see that the solar roof is already holding its own against roofing materials of any kind in California. In fact, that’s close to the price of two Tesla Powerwalls installed. So throw this in for added resiliency and call it a day.
The payback time for the solar roof varies from state to state and from utility to utility. So make sure you put in your own numbers before pulling the trigger on your own system. We have been dealing with this topic for months. You can find more information about the Tesla solar roof system here at CleanTechnica as the installation of our system progresses.
If you’re in the market for a Tesla, find someone local you know (e.g. someone you know true life) and use your reference code. If you don’t know anyone with a Tesla, find someone at your local compressor and try not to be a scare and ask them for their reference code (they don’t mind). If that doesn’t work, ask a coworker or distant relative, post on Facebook or Twitter, or just call Google. If all of this fails and it’s an odd day and not too sunny, you can use my Tesla referral link to get 1,000 miles of free recharge I think. Here is my referral code: http://ts.la/kyle623
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