Solar shingles: what they are, how they work, and how they compare

Solar shingles offer solar power with a sleeker roofline, but often at a higher price.

Solar shingles are small solar panels designed to resemble and replace traditional roofing materials, like asphalt shingles, with energy-generating alternatives. Rather than being mounted on top of a roof as most home solar panels are, solar shingles are incorporated into the roof itself, an example of building-integrated photovoltaics.

The advantage of solar shingles is largely aesthetic. They are known for being more expensive and less efficient than standard solar panels, although they may become more practical for many people as better technology improves their performance.

Solar shingles are an effective source of solar power, and even if they aren’t the most efficient or economical option, their aesthetic value is a valid incentive if you can afford them. Research suggests sleeker, less conspicuous solar equipment is more popular, and many people are willing to pay higher prices for solar power systems they consider more attractive—i.e., more camouflaged. If the low profile of solar shingles can appeal to homeowners who don’t like the looks of traditional solar panels, they might be able to help introduce new solar capacity on roofs that wouldn’t otherwise have it.1

To shed more light on this method of generating solar power, here is a closer look at solar shingles, including how they work and how they compare with other solar options.

How Do Solar Shingles Work?

National Renewable Energy Lab roof shingle testing in Golden, Colorado.National Renewable Energy Lab roof shingle testing in Golden, Colorado.

Solar shingles have been commercially available since 2005, and although they have evolved over the years, the basic idea is still the same: merging solar panels with the roof instead of just mounting them on top of it.2

All solar shingles are designed to function as both roofing materials and power sources, but they can achieve that dual identity in a few ways. Some solar shingles use silicon as a semiconductor, as do most conventional solar panels, while others rely on thin-film solar cells, which feature super-thin layers of certain photovoltaic materials, like copper indium gallium selenide (CIGS) or cadmium telluride (CdTe). The thinness of these solar cells makes them lighter and more flexible, both broadly useful qualities. While older versions of flexible thin-film solar roofing had to be installed on top of another roofing material, newer products are rigid and sturdy enough to serve as shingles themselves.

Like traditional rooftop panels, solar shingles convert solar energy into electricity by harnessing the flow of electrons released when a semiconducting material like silicon, CIGS, or CdTe is hit by sunlight. While solar shingles and solar panels generate electricity with the same fundamental photovoltaic effect, they do have significant differences in appearance, materials, and installation.

Installing solar shingles does not require a mounting system, for example, since they are not mounted on racks like other solar panels are. Solar shingles are instead attached directly to the roof deck in place of conventional roofing shingles. 

Solar shingles are typically installed at the same time the entire roof is being installed, either during new construction or when replacing an old or damaged roof. Waiting for this scenario helps reduce the expense of solar shingles, incorporating their cost into that of the overall roof installation, which was presumably needed anyway.

Installing solar shingles with a new or rebuilt roof also helps homeowners avoid replacing older but functional shingles before it is necessary, and it can be performed by a single roofing contractor—as long as the contractor has experience installing photovoltaic shingles, notes the U.S. Office of Energy Efficiency and Renewable Energy.3 Solar shingles can serve as the primary roofing material for a home, but in some cases they may replace old shingles only on certain parts of the roof.

The installation of solar shingles tends to be more expensive than that of traditional solar panels, especially if you want them to cover your entire roof. Solar shingles are mainly sold in more affluent areas, a project manager for a California solar contractor noted in a 2019 case study of a solar-shingle installation. Customers often call to ask about solar shingles, the project manager said, then experience "sticker [price] shock" and opt for traditional solar panels instead. Solar shingles are more economical, he added, if they're installed as part of a full roof installation.4

The efficiency and expense of solar shingles vary widely, depending on factors such as brand, installer, roof complexity, and amount of coverage. Popular brands for solar shingles or tiles include CertainTeed’s Apollo II, SunTegra, Luma, and Tesla, among others. Many integrated solar roofing materials offer conversion efficiency of about 15%, an expected life span of 20 years or longer, and enough durability to rival the weather resistance of traditional shingles. The cost of solar shingles for typical home could range anywhere from $30,000 or less to more than $100,000.

Tesla entered the solar shingle market in 2016, announcing a new solar roof that has since become an industry leader. Tesla’s solar roof features solar shingles that are “more than three times stronger than standard roofing tiles” and “engineered for all-weather protection,” according to the company. They can withstand winds up to 166 mph and hail up to 1.75 inches in diameter.

Close-up of Solarglass Roof, a roof shingle with integrated solar panels, from Tesla Energy, a division of Tesla Motors, on Santana Row in the Silicon Valley, San Jose, California.Close-up of Solarglass Roof, a roof shingle with integrated solar panels, from Tesla Energy, a division of Tesla Motors, on Santana Row in the Silicon Valley, San Jose, California.

The news about Tesla solar roofs is not all positive, though. In April 2021, Tesla CEO Elon Musk acknowledged the company has made “significant mistakes” with the solar roof project, leading to service delays and cost increases—with the latter affecting existing customers as well as new ones. Some customers are suing the company over the price increases. As an explanation, Musk has said “the complexity of roofs varies dramatically,” and Tesla has had trouble “assessing the difficulty of certain roofs.”

Tesla originally charged a flat rate for solar roofs regardless of complexity, then began factoring complexity into its pricing in early 2021. A complex roof reportedly could now cost more than $19 per square foot, but even a simple roof may cost $14 per square foot. Previous estimates from Tesla suggested a 10-kilowatt solar roof in California could cost around $34,000. With those increases and the now-required battery, the total cost of a Tesla solar roof may have risen by 30%, with some estimates in six figures.

The cost of solar shingles can vary by several factors, and it’s generally worth shopping around locally for quotes. Some brands may cost only $10 or $11 per square foot.  

Solar Shingles Pros and Cons

The most notable pro of solar shingles is their aesthetic value, which lets homeowners generate electricity with a roof that looks sleeker from the street, alleviating concerns for some people who dislike the appearance of traditional solar panels. Other pros include their endurance (many solar shingles are designed to withstand hail and hurricane-force winds) and their efficiency, which varies but can rival that of larger panels.

The main downside of solar shingles is their cost, which still renders them impractical in many cases unless they’re part of a newly constructed or rebuilt roof. They also may not be offered by some solar installers, and because they aren’t mounted on racks, there can be issues with sunlight exposure depending on the slope of the roof.

Solar Panels vs. Solar Shingles

Solar shingles are smaller than solar panels because their size is meant to resemble that of traditional roofing shingles. They also attach to the roof differently: Rather than resting atop special racks mounted on the existing roof, solar shingles are meant to integrate with the roof more seamlessly.

Solar panels and solar shingles have similar expected life spans of about 20 to 30 years, and because many solar shingles use similar materials as those in larger panels, their conversion efficiency may be comparable, too. The main differences tend to be aesthetics and price, with solar shingles typically offering a more streamlined look at a higher cost, although that price can vary widely.

Solar Tiles

Solar tiles are similar to solar shingles, but while the terms are sometimes used interchangeably, they also can refer to different types of roofing material. Solar shingles tend to be those designed to look like asphalt shingles, while solar tiles may mimic the appearance of conventional roofing tiles. Some companies sell both solar shingles and solar tiles.

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By Russell McLendon / Freelance Science Journalist

Russell McLendon is a science journalist and regular contributor to ScienceAlert. After graduating from the University of Georgia with degrees in journalism and anthropology, he spent three years as a newspaper reporter and editor before joining the startup Mother Nature Network (later merged with Treehugger), where he worked for 12 years as associate editor, science editor, and senior writer.

Now a freelance writer and editor, Russell covers a wide range of topics related to science and health, including astronomy, ecology, climate change, gardening, and human psychology.

When he isn’t working, Russell plays with his son, draws, runs, watches birds, and grows tomatoes for the squirrels in his garden.

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(Source: treehugger.com; July 20, 2021; https://tinyurl.com/2f2kpbus)
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