Should I Wait for Tesla’s Solar Roof?

If you’re interested in solar power for you home, you might be tempted to get one of Tesla’s new solar roofs. A variation on the solar shingle, the solar roof is composed of roofing shingles that look totally normal when viewed from the street level. But within each solar shingle is a solar cell capable of harnessing the sun’s energy and transforming it into electricity you can use to power your home.

The precise cost of the roof depends on the balance between regular and solar tiles. The cheapest option blends 40 percent solar tiles and 60 percent regular tiles, and costs roughly $37,000. Increasing the percentage of solar tiles to Tesla’s recommended maximum of 70 percent would push the total over $50,000. (Installing more than 70 percent solar tiles is not allowed due to building regulations.) And according to Tesla’s own calculations, installing a solar roof on a typical home in Maryland would cost $52,000.

Replacing a roof with traditional shingles, on the other hand, costs only $9,000 to $14,000. Installing more expensive asphalt tiles could cost around $20,000, and installing premium slate tiles could cost up to $45,000.

Of course, the solar roof doesn’t just replace roofing shingles. It also produces solar power. According to PowerScout, a California-based solar startup, the average cost of a residential solar energy system is about $20,000.

But even compared to traditional solar panels, the solar roof is slightly more expensive. Traditional solar panels provide energy at a rate that averages around $3.25 per watt. Tesla’s roof produces energy at a rate that hovers around $4.75 per watt-46 percent higher than the average.

In other words, the total cost of both replacing your roof and installing regular solar panels could range anywhere from $29,000 at the low end up to $65,000 at the high end. That makes Tesla’s solar roof one of the most expensive roofing and solar options on the market. Even the tiles that don’t produce solar energy cost $11 per square foot-almost twice as expensive as the average roofing tile.

Of course, like all solar energy systems, these added costs will be offset by the savings you’ll see on your electric bill. Rebates, tax credits, and other financial incentives will further drive down the real cost of Tesla’s solar roof.

Apart from cost, some people might be put off by the very idea of a solar roof. Conventional solar panels have been around for over 40 years. They’re a familiar, time-tested technology with a reliable track record. But solar shingles are hardly new: the first solar shingle was patented in the 1970s, and they’ve been commercially available since 2005.

Still, even if the technology is mature, Tesla is new to the field. Tesla subsidiary SolarCity – which is leading the development, manufacturing, and installation of the solar roof – has almost a dozen years in the industry. But even big companies have struggled to make solar shingles a viable product.

Take Dow’s Powerhouse line of solar shingles, for instance. Dow debuted its solar shingles in 2009, and like Tesla’s, they could be laid alongside conventional, non-solar tiles. But in 2016, just months before Musk announced Tesla’s foray into the solar market, the chemical giant ceased manufacturing its Powerhouse modules. Analysts blamed Powerhouse’s failure on the fact that Dow had trouble articulating the advantages of its solar roof over regular solar panels. The Powerhouse was both less efficient and more expensive than regular solar panels. And Dow was beset by internal upheavals and reorganization as it merged with DuPont.

It’s hard to know how Tesla’s bid for a piece of the solar market will will play out over the long term, but judging by preliminary reports, the solar roof has a bright future. Preorder installations for well into this year sold out in a matter of weeks.

Why are people so excited about Tesla’s solar roof? Tesla CEO and founder Elon Musk has said that the solar tiles will be lighter and stronger than regular roof tiles. The tiles also come with two generous warranties, one that covers the physical durability of the tiles for the lifetime of the house and a second that covers the solar functionality of the tiles for 30 years. That’s five years more than the standard 25-year warranty on solar panels.

Moreover, some people consider standard solar panels ugly, and may gravitate towards Tesla’s solar tiles as an aesthetically pleasing alternative. While only gray and textured black glass tiles are available now, two additional colors - ”slate” (a mosaic of earth tones) and “tuscan” (a light brown) - will be available this year.

Unfortunately, the same tinting that makes the tiles so attractive also reduces their efficiency, as less light can penetrate the tile and reach the solar cell within. Tile efficiency will also likely be hurt by the fact that the tiles are flush with the roof. Standard solar panels, by contrast, are typically installed with a gap beneath them that allows for air cooling. The solar shingles are likely to reach much higher temperatures, further reducing their efficiency.

While Tesla hasn’t explained exactly how the installation process works, solar shingles are typically easier to install than solar panels. Based on prior examples of similar technology, installation will probably be performed primarily by roofers. That’s why Tesla hired at least 50 additional roofers last year. An electrician will still be required to connect the tiles to an inverter and the grid.

Tesla has said that installations will begin this year and take about 5 to 7 days-the same amount of time that it takes to install a standard roof. If you’re building a new home or due for a roof update, a Tesla roof could be a good option. You’d get the benefits of solar power and a new roof at the same time, rather than paying once for a new roof and then again for solar panels. But if you have a relatively new roof and are only looking to add a solar energy array to your home, a traditional solar array may still be your best option. To find out how much a solar roof would cost you, check out Tesla’s solar roof calculator.