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Maiko Kiis, Marketing Manager at sunstone finds out if solar roofs are worth the money and tells us what we need to know about building integrated photovoltaics (BIPV)

Traditionally, going solar has meant installing a ground-mounted solar farm or panels on the roofs. Putting a layer of PV panels on an existing roof with the aim of going green doesn’t make sense – up to 50% of the excess is used on the roof, making the #gogreen #greenwash. But roofs and solar panels can and should be the same when it comes to resource efficiency.

Building Integrated Photovoltaics (BIPV) are revolutionizing the way homeowners and businesses can integrate solar energy production into their buildings. BIPVs are multifunctional: they generate renewable energy for your home while being an integral and essential part of a permanent building structure. There are many building elements where BIPVs can be applied, such as roofs, facades, windows, skylights and balcony railings. The list doesn’t stop here. Let’s take a deeper dive into sunroofs.

Building-integrated sunroofs

Residential construction is open to new technologies and solutions that integrate renewable energy production into building structures, especially roofs. Solar panels fit architecturally just right with the building. Solar roofs have become popular since 2016 and today there are dozens or even hundreds of integrated solar and shingle manufacturers around the world, all with their modifications. There are different types of solar roof products available and essentially they are all mini solar panels designed to look and function like conventional roofing materials.

Why choose an integrated sunroof?

The main argument for BIPVs is the visual appeal, it just looks much nicer than regular panels. BIPV makes an architectural whole, while ordinary PV looks like a foreign body on your roof. If you have an existing home, installing regular panels may be more cost-effective, but for new construction, BIPV is more cost-effective. The difference is in saving on traditional roofing materials and reducing the workload. Ordinary solar panels can never be placed in heritage and protected areas, while BIPV does have that option. By producing solar energy and maximizing self-consumption, you are protected against potentially larger fluctuations in electricity prices for decades. In the real estate market, too, energy-efficient buildings with building-integrated solar panels are significantly more attractive to buyers.

While the benefits of integrated solar power are obvious, 99% of rooftop solar installations today are still done with regular PV for two main reasons. Firstly, BIPVs are more expensive and secondly, they are often overdeveloped, making preparation and installation time consuming and expensive.

“Solar roofs are designed to withstand rain, wind and hail and should easily last 25 years or more, as are all types of roofing alternatives.”

How long does a sunroof last?

Most solar shingles last 25-30 years and retain about 80% of the original output. Towards the end of their lifespan, the efficiency decreases, which is normal for all solar panels. Solar roofs are designed to withstand rain, wind and hail and should easily last 25 years or more, as are all types of roofing alternatives.

Building integrated solar roof maintenance

Solar panels are virtually maintenance free. There are no moving parts in the system that require immediate maintenance. In the spring, after the snow has melted and the plants and trees have been pollinated, dirt can cover the panels. It would be wise to remove tree leaves and branches from the panels, which cannot be washed away by rain and hinder the electricity generation potential. In areas with a lot of pollen and dust, the panels should be washed periodically. In general, it is sufficient to soak the panels from the ground with a hose, which will remove most of the dirt. Cleaning agents are not required to clean the panels. Rain is generally the best cleaner.

Solar Roof Efficiency

The dark BIPV panels (eg solar shingles) have a comparable efficiency in contrast to ordinary solar panels. The roofs of private homes are generally large enough to bring the home’s energy consumption to near zero energy (in the case of new homes) or to increase the energy label of an existing home.

In Northern Europe, for example, stationary installations facing directly south and with a slope of 35-45° are the most efficient. The east-west PV installation loses up to 20% in productivity, but covers a larger part of the daily consumption (production also in the morning and evening, not only during the day). The productivity of PV installations with lower slopes (including integrated roof solutions) is also up to 20% lower, and furthermore, such solutions are not preferred by tile manufacturers (installations below 18° require a 100% waterproof subfloor). Shadows periodically falling from trees or surrounding buildings do not hinder the installation of solar systems, but should preferably be avoided. Shadows, incorrect weather conditions and roof pitch can significantly affect the potential of the solar panels.

Going off-grid with a sunroof

Most installations are connected to the grid, which does not protect you against outages, but does provide convenience. In some countries, unused solar energy can be sold back to the grid, while in others you get credit, reducing your electricity bill in the winter. While energy storage systems are still some time away from reaching the masses due to high prices, they are sure to make their way into homes in the near future. There are already an increasing number of solar roof installations for off-grid homes and cabins today, but we should consider that a niche. The sad reality is that in many countries going off-grid without a generator is not possible – there is simply not enough solar radiation during some seasons.

Is a sunroof worth it?

The economic factor of solar roofs is that they have a double function. They are especially beneficial for homeowners who need a new roof and who want to maintain aesthetics and roof functionality. In many countries there are still subsidies for local sustainable energy production, which makes solar energy even more attractive. A sunroof could potentially reduce an efficient home’s electricity bill to nearly zero. Despite the high initial investment, sunroofs are often worth it. If you’re looking for a way to save the most on your electric bill, you’re probably better off opting for a traditional solar panel installation. Keep in mind that a traditional roof will not lower your electricity costs nor will it recoup the investment.

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