Integrated Solar Tiles: Invisible Power Producers

A tile that covers your roof and simultaneously produces environmentally friendly electricity? What might sound like hitting the jackpot is a reality: The integrated solar tile. This remarkable invention serves as both a roofing material and a power generator. In the following article, discover the advantages and disadvantages of these high-tech tiles compared to conventional photovoltaic systems. Find out when installing them is a worthwhile investment, or when it might not be, and get insights into the potential costs you'll incur.

28.08.20237 min7'

Invisible Solar Tiles on a Swiss Single-Family House Overlooking a Lake

Sustainability and aesthetics—two topics that are gaining increasing significance in today's world. When it comes to photovoltaic systems (PV), these themes sometimes collide. While some appreciate traditional rooftop solar panels for their ecological benefits, others consider them a visual eyesore. Large-scale integrated solutions, like in-roof installations that become part of the house's structure, offer a slightly more inconspicuous option. However, the undisputed champion in terms of design is the solar tile: These small integrated modules blend the aesthetics of classic roofing tiles with the functionality of photovoltaic arrays.

But what about the efficiency of these elegant tiles? Can they rival the performance of standard PV systems? When is the investment in solar tiles justified, and what kind of costs should you anticipate? We've had a conversation with Patrick Imholz, an expert on solar tiles from Freesuns AG, and together, we provide you with answers to these pressing questions!

What Is a Solar Tile?

Solar tiles function much like conventional photovoltaic systems: they convert the sun's radiation into electrical energy, or in other words, electricity. However, they consist of significantly smaller solar modules that mimic the appearance of traditional roofing tiles. Typically constructed from materials such as slate, glass, and plastic, these tiles seamlessly blend into the overall aesthetics of your roof.

House Covered with Solar Tiles in Switzerland

Performance of Solar Tiles

Solar tiles are generally considered to be slightly less efficient than traditional rooftop solar panels due to their lower concentration of solar cells per square meter. Nevertheless, the compact format of these modules allows for installation in areas where larger rooftop or in-roof installations might not be feasible. Since solar tiles can cover more roof area, the efficiency difference can be minimized.

The performance of solar tiles also depends on several other factors. As with all photovoltaic systems, the roof's orientation plays a crucial role. For optimal performance, your roof should face south and have a minimum slope of 10 degrees. A roof with a slope of around 30 to 35 degrees maximizes the tiles' power output.

Additionally, the roof's surface area is a significant consideration. Expert Patrick Imholz recommends, "For a single-family home with an average energy consumption of around 4500 - 5000 kilowatt-hours, solar tiles make sense on a surface area of approximately 40 - 50 m²." Lastly, the color of the tiles impacts their efficiency. In general, darker tiles can absorb more sunlight, resulting in higher electricity production.

When all relevant factors are considered, the performance of solar tiles can be comparable to that of conventional rooftop installations.

Costs & Incentives

The saying "no pain, no gain" applies to solar tiles as well—albeit indirectly. Enhancing the beauty of your roof comes at a (slight) cost to your wallet. These stylish tiles, unsurprisingly, are more expensive than conventional roofing or larger photovoltaic arrays. The purchase price of the tiles is accompanied by costs for installing the necessary electronics and wiring each individual tile.

Apart from the direct acquisition and installation costs of the tiles, the roof's substructure should not be overlooked. Patrick Imholz explains, "It doesn't make much sense to install new solar tiles on a 30-year-old roof structure. In such cases, the roof's lath structure also needs to be inspected and renewed. The costs for renovating the roof structure can be underestimated. Installing solar tiles is particularly worthwhile when a roof renovation is already planned, and the costs for a new roof structure, underlayment, counter battens, and the like have already been factored in. Adding up all the costs of a roof renovation, along with the acquisition and installation costs of the solar tiles, you should budget around CHF 800–1000 per square meter of solar tiles for a single-family home with average energy consumption. For a roof area of 40m², that's approximately CHF 32,000.

If you have additional budget available, investing in an energy storage system is recommended. With this, the generated electricity can be stored and used on rainy days or at night, reducing reliance on external power sources. Patrick Imholz also suggests considering this investment: "With an energy storage system, you can increase the self-consumption of the generated electricity from 30% to 60%. The more electricity you consume on your own, the more economically viable the photovoltaic system becomes for you." However, energy storage systems come at a cost, starting at around CHF 6,500 for a single-family home.

Before you recoil at the total amount, remember that you can apply for subsidies for investments in renewable energy! Integrated systems (large in-roof modules and solar tiles) are generally supported by more funding from the government, as they contribute to the preservation of the local environment. Moreover, a significant portion of the investment can be deducted from your taxes.

In the end, the rule of thumb is: The higher your received subsidies and the more you consume your self-generated electricity, the sooner you'll recoup the acquisition costs of the photovoltaic system—usually within a maximum of 20 years.

Pros and Cons of Solar Tiles

So, when do solar tiles make sense for you, and when does opting for a traditional PV system make more sense? Here's a quick overview of the main pros and cons of solar tiles:

Advantages of Solar Tiles:

  • Two-in-One Solution: Solar tiles serve as roofing and electricity generators simultaneously. This investment in a 2x1 solution is particularly beneficial when a roof renovation is planned or when constructing a new building.

  • Appealing Aesthetics: Solar tiles are less conspicuous than traditional photovoltaic panels and blend harmoniously with the building's overall design. Imholz Expert Tip: "Because of their discreet appearance, solar tiles are particularly suitable when the building is under heritage protection or when the architectural value of the property is crucial for the owners."

  • High Flexibility: Each solar tile is an independent solar cell, allowing for greater flexibility on uniquely shaped roof surfaces. Unlike large in-roof modules, even smaller angles can be covered using specially tailored angle tiles.

  • No Additional Mounting Elements Required: Unlike rooftop installations, solar tiles don't need special mounting elements like frames, brackets, or other fasteners.

Disadvantages of Solar Tiles:

  • No Retroactive Installation: Unlike rooftop systems, solar tiles can't be easily added to an existing roof.

  • Complex Electronics: Due to the numerous connections and circuits between individual tiles, solar tiles are technically more complex than a single large module.

  • Lower Performance: While solar tiles are slightly less efficient than larger modules, they cover areas where there's no space for larger modules. Overall, solar tiles generate only slightly less electricity.

Conclusion: Solar Tiles, Yes or No?

In conclusion, solar tiles are particularly advantageous when a roof renovation is planned or when constructing a new building. If you have a unique and complex roof shape or want to cover only smaller areas, solar tiles also make sense. Moreover, if your house has architectural value or is heritage-protected, solar tiles can be your ideal path to environmentally produced electricity. On the other hand, solar tiles might not be suitable if you recently renovated your roof or have less than 40m² of available space. They are also not recommended for flat roofs.

Yes, I Want Solar Tiles. What Should I Do?

Have you decided on solar tiles? Follow this step-by-step guide—next stop, solar-powered roof!

  1. Feasibility Check: In the first step, assess how suitable your roof is for solar energy. You can use the map for Solar Energy Utilization provided by the Swiss Confederation. Simply enter your address and quickly determine how well your property suits a photovoltaic system. For existing buildings, the map also indicates the roof side most suitable for the installation.

  2. Contact Specialists: Reach out to a solar tile manufacturer or planner.

  3. Detailed Planning: Your roof will be measured using a drone, and a 3D model will be developed based on the measurements. Ensure that your chosen company provides accurate predictions regarding expected subsidies, roofing costs, and material expenses.

  4. Installation: Installing solar tiles takes no longer than a traditional roof covering, around 2 weeks. Keep in mind that longer material delivery times should be considered, and craftsmen currently have busy schedules. So, start planning early!

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