In 2010, BGP realised six residential buildings on the Fehlmann areal in Winterthur. From August 2020, two new buildings complete the development of the area, tying in...
Fehlmann housing development
Architect Sebastian El Khouli
Partner, BGP Architects
``We have a neighborly vision for the use of photovoltaics. For a long time it was about self-sufficiency, houses that function independently of public utilities. We see the next step in close-knit and, above all, solidarity-based energy associations. Not every house produces electricity in these. That is neither realistic nor necessary. In order to implement this vision, however, an urban development and political change of heart is required.``
The concept of urban planning

In 2010, BGP realised six residential buildings on the Fehlmann areal in Winterthur. From August 2020, two new buildings complete the development of the area, tying in with the existing urban planning and design. From a distance they are undistinguishable from the existing buildings. However, depending on the incidence of sunlight, a closer look will show that instead of black enamelled glass panels, the facades are now cladded with photovoltaic modules. For the expansion of the site, the architects combined photovoltaic elements in the facade with a conventional PV roof system, as this has tripled energy production and significantly increased self-consumption.

Like the first-stage buildings, the new developments are based on a simple basic structural principle with a central staircase.

Contrast between the transparent elements and deep black PV glass modules.

Almost all of the 14 new rental apartments open onto the outside space on three sides and give the residents the feeling of living within a green space.

Building characteristics
  • Building typology
  • Construction type
  • Year of construction
  • Energy reference surface
    925 m² (unit 23) + 807 m² (unit 25)
  • Energy index
  • Energy labelling
  • Acquisition
    Competition by invitation, 1st prize 1999
Architect Luigi Snozzi
“Every intervention is an interference, interfere with reason.``
Active solar surface 238m² 590m²
Active solar surface ratio >50% >50%
Peak power 46.9 kWp 81.9 kWp
Building skin application Flat roof Cold facade
Energy production
Source: Solarville (roof 42.700 kWh/y), BGP (facades 40.000 kWh/y)
Source: BGP
Building skin
  • Application
    Standard modules are laid on a metallic support system.
  • Description
    Insulated concrete roof.
  • U value
  • Fastening system
    Continuous fixing system (aluminium tracks)
  • Other

View of the roof with the photovoltaic installation.

  • Application
    PV cladding integrated in a cold facade
  • Description
    Concrete walls with external insulation layer in mineral wool (18 cm).
  • U value
    0.22 W/m²K
  • Fastening system
    Continuous fixing system (aluminium tracks)
  • Other

The windows are staggered on each floor to generate a subtle variation in the facade.

  • Application
  • Description
    Triple glazing with aluminium frame.
  • U value
  • g value
  • Other

View from the attic terrace.

View of the attic terrace.

BIPV module
  • Product
    VSG Laminated safety glass module
  • Manufacturer
    Ertex solartechnik GmbH
  • Cell technology
  • Front glass type/customization
    Digital ceramic print on glass/glass BIPV modules
  • Cell colour
  • Dimensions
    Various sizes, the largest module measures 2690×1430 mm.
  • Specific power
  • Specific weight
Technical details

The facades are load-bearing, so that all interior walls could be constructed as non-load-bearing solid walls. The facade takes on a multitude of tasks: protection, climate regulation, representation, identification. A central concern was to add electricity production as an additional feature and to allow an almost seamless connection to the existing buildings without reducing the urban and architectural qualities of the development. To achieve this were used cladding panels very similar to those installed in the first six buildings. However, looking closer, depending on the angle of incidence of the sun, one can see that instead of black enamelled glass panels, photovoltaic modules are cladding the buildings.

Hotspot image
Vertical section
Hotspot image
  • Total cost of the two buildings
    4,700,000 CHF (BKP2)
  • Cost per m³  

Urban living in green areas.

Parties involved
  • Owner
    AXA Investment – Managers Schweiz AG
  • Architect
    Bob Gysin and Partner AG
  • Civil engineer
    Dr. J. Grob & Partner AG
  • Photovoltaic consultant
    energiebüro ag
  • Photovoltaic installer
    Planeco GmbH
  • Facade installer
    K&K Fassaden AG
  • Photo
    Roger Frei
Awards and recognitions
  • Awards

    Prime Property Award 2012 (for first phase)

  • Publications