An interview with the designer couple Regula Trachsel and Sascha Schär about their project: their home/office building.

New construction of a residential and business building according to the cradle-to-cradle principle, in Zweisimmen, Bern.

Solar roof with an area of 130 m2, a capacity of 14 kWp and an annual output of about 12,000 kWh.

SUNSTYLE AG: Ms Trachsel, why did you choose this solar roof?
Ms Trachsel: We came across SUNSTYLE® while researching simple and flexible PV modules. As we were planning an unusual roof shape, the connections to the eaves and barge board with SUNSTYLE® seemed very easy and inexpensive to solve.

SUNSTYLE AG: What was your first impression?
Mr Schär: At first glance, the roof just seems to be a roof and not a photovoltaic installation! We like this a lot!

SUNSTYLE AG: Which characteristics were important for you?
Mr Schär: For our home and office building, which we built according to the cradle-to-cradle principle, it was important for us to choose a product that could be dismantled and recycled easily. I see great potential in the simplicity of the system with its wood counter battens and glass modules.

SUNSTYLE AG: Your installation has been in operation since June 2014. Does it produce as much energy as was projected?
Ms Trachsel: Yes, the winter months have been a pleasant surprise! In contrast to nearby PV installations, our roof has had hardly any snow. The snow just slides off the eaves after a short time.

SUNSTYLE AG: Thank you for the interview and the good collaboration.


Expectations of the energy performance of buildings will continue to increase. At the same time, we want to move away from fossil fuels and nuclear energy, and towards renewable energy sources. A fully integrated solar roof that converts clean and unlimited solar energy into electrical energy stays takes this trend into account. The SUNSTYLE® solar roof connects the two objectives in a harmonious manner: first, as a high quality construction element, it offers sustainable weather protection; and, second, it enables efficient electricity production over the entire roof surface.

Manufacture and quality

The SUNSTYLE® solar tile was developed as an energy-efficient, long-lasting construction element. The crystalline solar cells integrated into the tile are embedded in a flexible, stabilising layer of ethylene vinyl acetate (EVA). They are protected on the front by hardened solar glass, and on the back by either a layer of resistant plastic (Tedlar) or hardened safety glass (ESG). All these factors combined with many years of expertise make SUNSTYLE® an extremely long-lasting construction element.

The coloured solar tiles are pigmented on the inside of the front glass using a specially developed technology. Thanks to the use of UV-stable pigments, this enables long-lasting, colour-fast modules to be manufactured. The internal pigment layer also ensures that the self-cleaning function of the glass surface is maintained. The solar tiles are produced in both glass-film and glass-glass designs and are based on proven standard components.

Quality and Certification IEC 61215, IEC 61730 (protection class II)
External product validation CSTB (Centre Scientique et Technique du Bâtiment)
Snow load testing (SUPSI) Snow load: >15,4 kN/m2 at slope 0 – 30°
Coloured glas-glas tiles IEC 61215, IEC 61730, UL 1703, IEC 61701, IEC 62716


Installation - Robust and accessible - SUNSTYLE solar roof The solar tiles are screwed directly into the sub-roof structure using a fitted sub-construction made of wood or stainless steel. The size and weight of the solar tiles are designed in such a way that it takes only one roofer to lay them. The electrical connectors on the back of the solar tiles ensure foolproof and safe cabling, which can be done at the same time as installation of the roof.

Product range

«Thanks to the broad range of components, it is possible to achieve a homogeneous roof structure and high efficiency.»
Solarziegel in Solarschwarz, Ziegelrot und Schiefergrau

Solar tiles in solar black, brick red and slate grey

Coloured solar tiles in brick red and slate grey are a new addition to the range. They bring new possibilities in colour design and architectural integration of the solar roof. The surface of the brick-red and slate-grey solar tiles is made from structured solar glass, optimised for light transmission, which improves the colour perception from different viewing angles.

In addition to the basic tiles, tiles without solar cells for roof areas not exposed to the sun and transparent glass tiles to bring natural light into the building are also available. Edge tiles, which result in the ideal roof finish and also produce electricity, complete the product range. The system can be adapted perfectly to special roof shapes using colour-matched aluminium composite panels, which can be cut to size on site.

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