Last Updated: Oct 7, 2022
Transitioning into a zero-carbon future will undoubtedly require significant changes to generate the energy we need to power our homes. Though commercial solar power is expected to grow around 2 GW per year from 2021-2025, household or residential solar power is another major renewable energy revolution player. For most people, residential solar power is about placing solar panels on your roof, garage, or other areas where you receive abundant amounts of sun. The number of residential solar systems installed is increasing rapidly. In 2010, new systems accounted for only about 250 MWdc. Fast forward to 2020, and new installations added over 3,000 MWdc of solar power to the energy mix.
The advantages are apparent. With solar at home, you have the exciting opportunity to harvest energy to power your home, cut your electricity bills, and reduce your household carbon footprint. However, as technology has developed, different options to take advantage of the free and abundant solar energy are beginning to appear. For homeowners whose roofs are shaded or poorly oriented, community solar programs are continuing to grow. Even if you do not own a home, people in many regions around North America can purchase green power for their rental, apartment, or office.
Today, companies are taking different approaches towards developing residential solar PV systems that meet homeowner's energy demands while also providing aesthetic qualities for the house. Solar roofing or shingles are an investment worth exploring for those who are turned off at the aesthetics of large solar panels. With solar roofing, the solar array is an integrated part of the roof's protective outer layer. This feature can make the solar array less obtrusive and save on other roofing materials.
Below, we will explain some of the current developments in solar roofing technology and explain the advantages and drawbacks of this exciting development in residential solar PV systems.
Like solar panels, solar roofing is designed to capture the energy from the sun that is shining on your roof and turn that energy into a usable power source for your home. Though different types of solar roofing products are available, they are all essentially mini solar panels designed to look like and function as conventional roofing materials. The main market driver of solar roofing products was consumer demand for solar panels that were less noticeable and conspicuous. Though some people appreciate the "futuristic" look of a roof clad in solar panels, others lament the loss of traditional roofing appearance. Solar roofing, then, is made to resemble asphalt shingles or slate tiles while also producing electricity. All of the different types of solar roofing are known as building-integrated photovoltaics (BIPV).
Solar shingles are a widely produced option in the solar roofing industry. Companies like Tesla, SunTegra, and CertainTeed, have developed solar roofing products based on integrated solar panels that mimic the size and shape of typical asphalt shingles or roof tiles. These solar shingles blend into the roof's look better than traditional solar panels. In addition, they don't require extra shingles or other types of roofing materials underneath them.
Some companies produce separate, shingle-sized solid panels that resemble individual shingles. Other companies are developing semi-rigid designs containing several silicon solar cells sized more like conventional shingles. The newest systems rely on thin-film solar cell technologies that match traditional shingles both in size and flexibility. Homeowners can also find larger solar roofing panels that are sized more like regular solar panels. However, at the same time, they act as an autonomous roofing solution. Integra, for example, has a building-integrated photovoltaic panel that produces 100 watts DC rating per shingle.
The development of solar shingles was met with excitement by many homeowners. Besides the improved aesthetics of solar shingles, many homeowners thought that solar shingles might reduce the cost of residential solar installation by absorbing the cost of the roof itself. Across the United States, the average cost for a roof replacement is $8,300. Thus, one of the enticements with solar shingles was that these renewable energy-producing panels could also eliminate the costs of purchasing and installing a new roof. Consumer enthusiasm for solar shingles ultimately led to the development of other types of solar roofing alternatives, including:
We will dive into each below.
Forward Solar Roofing, a San Francisco, USA company, has developed solar metal roofing that looks like regular metal roofing and comes in various colors. Their multi-layer system includes a glass coating, color coating, and a layer of monocrystalline solar photovoltaic cells. The wiring and attachment systems are hidden underneath the metal for a clean look. Several other layers include durable tempered glass, optical chromatic cloaking, silicon solar cells, and galvanized metal panels, all on top of a vented racking system.
The average cost for installing this roof is around $12.75 per square foot, towards the high end of average prices for standard metal roof installation. However, it is also significantly less than a Tesla solar shingle roof.
Suppose you are building new or need a roof replacement. In that case, this investment could be paid off in very little time due to energy savings, not to mention tax incentives or rebates that may be offered in your area. Forward Solar Roofing guarantees its solar metal roof for 30 years and has a 2-3 day installation time.
With interlocking solar panel roofing, the regular framed solar panels are mounted directly to the roof, overlapped, and sealed. The panels serve as the weatherproof outer layer over the roof section they occupy, so no asphalt or tile roofing is needed underneath them. They are close to the roof deck and don't have any exposed aluminum racking, making them visually lower-profile.
While it is not quite as 'hidden' as solar shingles or solar metal roofing, the interlocking solar panel roofing has the advantage of being relatively simple to install. This system can also use standard solar panels to keep costs competitive, competitively available from many manufacturers.
At least two companies - GAF Materials Corporation and SunTegra - produce interlocking solar roofing systems. The entry of GAF into this market signals a shift because GAF is one of the oldest and largest roofing materials companies in North America. When one of the largest roofing companies in the county is offering solar roofing options, the concept has joined the mainstream.
The exact amount of energy produced by solar shingles will depend on their size. On average, however, each solar shingle should produce between 13 and 63 watts of energy in optimal conditions depending on the brand of solar roof shingles. On the downside, solar shingles are still lagging significantly behind regular solar panels regarding efficiency. According to research done by Energy Sage, "typical solar shingle brands range from 14 to 18 percent efficiency, whereas most solar panels are 22 to 23 percent efficient." Because solar shingles will most likely cover your entire roof, the lower efficiency will not necessarily impact the overall solar energy output.
Solar shingles and other solar roofing products are lightweight and easy to install. Like all types of roofing alternatives, they are designed to withstand rain, wind, and hail and should easily last for 25 years or more. For example, Tesla's Solar Roof comes with the following specifications/warrantees:
Tesla's Solar Roof is by far the most popular and well-known solar roofing option. The original price was $21.85 per square foot for Tesla's solar shingle roof. However, Tesla's roof price has increased drastically in 2021, with some cases seeing a price increase 50% above earlier quotes. Other options include:
We will look at each of these below.
The CertainTeed Apollo II offers a robust rooftop solar energy production into a low-profile roofing system. Their solar shingles can be installed with either a new or existing asphalt shingle roof. An Apollo II system offers clean energy without the bulky look of racks and panels. Also, the high-efficiency monocrystalline silicon solar cells provide a power rating of 70 watts per solar shingle.
The Luma Solar Roof boasts solar shingles rated to exceed category five hurricanes and has an impressive 80 watts per shingle energy rating.
SunTegra Shingles attach directly to an existing roof and integrate with composition shingles and other low-profile roofing materials. Their roofing systems use 50 percent fewer parts than a conventional rack-mounted solar system and install in half the time.
As we mentioned above, Forward Solar Roofing is an affordable option that looks like standard metal roofing. It is constructed with a multi-layer system where the wiring and attachment systems are hidden underneath the metal, providing a clean look for your solar roof.
Solar roofing offers the advantages of having renewable energy production integrated directly into your roof. Most solar roofing products will also drastically improve the aesthetics when compared to standard solar panel mounting. For example, Tesla's Solar Roof is made of glass-faced tiles that use hydrographic printing to give the tile an appearance that looks remarkably like slate, clay tile, or a dark shingle. As solar roofing options increase in popularity, they are also becoming more affordable.
On the downside, solar shingles and solar roofing continue to be significantly more expensive than regular solar panels. They are certainly not the most cost-effective option for residential renewable energy production. That said, a solar roof can potentially cut the electricity bill of an efficient home down to near zero.
So, If you need a new roof and also want to invest in residential solar PV, then solar roofing might be the most cost-effective option for you.
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.