The project is geared towards the optimal use of solar energy, while at the same time achieving high quality architecture featuring elements that blend optimally with their...
Felix Vontobel
At the Swiss Solar Award 2013
``Any newly built facade and roof surface should be able to generate electricity in addition to its function as building envelope.``
Winter Plus Energy Building

The project is geared towards the optimal use of solar energy, while at the same time achieving high quality architecture featuring elements that blend optimally with their surroundings. The entire building envelope consists of integrated photovoltaic modules. Flexibility and adaptability are evident both in the load-bearing structure and in the way it is used: the building can be used either as a single-family house or as two separate residential units. The Winter Plus Energy project meets the requirements of the Minergie-P and Minergie-A building standards.

Architectural drawing, ground floor. Source: Nadia Vontobel Architekten GmbH.

Sol’CH blends into the village of Poschiavo and the surrounding landscape.

Shape and colour of the Plus Energy Building (PEB) change depending on the viewpoint and incidence of light.

Building characteristics
  • Building typology
  • Construction type
  • Year of construction
  • Energy reference surface
    375 m²
  • Minergie energy index
    -86.9 kWh/m²yr
    The Minergie index is defined as the weighted total energy demand for heating, hot water, ventilation, air conditioning, lighting, appliances and general building technology. It produces the building’s own electricity production.
  • Energy labelling
    Minergie-P and Minergie-A
Active solar surface 187m² 284m²
Active solar surface ratio >100% >99%
Peak power 34 kWp 30 kWp
Building skin application Solar tiles Cold facade
Storage 3000 l hydraulic tank for heating and hot water production approx. 50 kWh
Bi-directional car battery approx. 25 kWh
Energy production
Source: monitoring of installation production June 2021 - March 2022
Building skin
  • Application
    Solar tiles integrated in a pitched roof
  • Description
    Wooden gable roof insulated with 26 cm of mineral wool
  • U value
    0.15 W/m2K
  • Fastening system
    The support hooks are screwed onto the roof battens. Modules with a laterally integrated water profile are laid similarly to conventional roof tiles.

The photovoltaic modules are laid on top of the wooden roof battens.

  • Application
    PV cladding integrated in a cold facade
  • Description
    Concrete walls insulated with 26 cm of mineral wool
  • U value
    0.18 W/m2K
  • Fastening system
    Continuous fixing system (aluminum tracks)

Sunage BIPV modules are secured to the facade using horizontal aluminium rails.

Detail of fastening system.

  • Application
    Windows and skylights
  • Description
    Triple glazing with wood-metal frame
  • U value
    0.60 W/m2K
  • g value

Windows are equipped with triple glazing and a wood-metal frame.

View of the building entrance.

The complete building envelope consists of integrated photovoltaic modules.

BIPV module
  • Manufacturer
  • Cell technology
  • Cell colour
  • Front glass type/customization
    Facade modules: front float satin glass, 4 mm, uniform Suncol colour / back float glass, 4 mm, clear
    Roof modules: solar front glass, 3.2 mm, transparent / back solar glass, 3.2 mm, black
  • Dimensions
    Different module sizes (the most repeated facade module size is 1.00×1.50m, the most repeated roof module size is 1.00×1.05m)
  • Power
    Depends on the size of the PV module, each type of module has a different number of cells and a different power output.
  • Specific power
    Facade modules: 115 Wp/m2
    Roof modules: 180 Wp/m2
  • Weight
    Depends on the size of the PV module
  • Specific Weight
    Facade modules: 23 kg/m2
    Roof modules: 18 kg/m2
Technical details

The entire building envelope is composed of photovoltaic modules, which simultaneously assume the function of power generator as well as being the facade cladding. The opaque, dark surface of the photovoltaic facade with its anthracite and brown tones contributes to a harmonious integration into the surrounding landscape.

Hotspot image
Vertical section – eave
Hotspot image
  • Total cost of the building
  • Price per m³  

Northen view of the building.

Parties involved
  • Owner
    Ursula & Felix Vontobel
  • Electrical layout & installation
    Vassella Energie Sagl
  • Mechanical installation
    Caotec SA
  • Photo
    Nadia Vontobel Architekten GmbH
Awards and recognitions
  • Winner of the Austrian “Innovation Award for Integrated Photovoltaics 2022”, organized by the Austrian Photovoltaic Technology Platform (TPPV), award for BIPV in residential buildings

    Final selection Constructive Alps 2022

    Recognition of the Sol’CH project as a pilot and demonstration installation: maximising the generation of winter electricity and use of all facades and roof surfaces through BIPV (building integrated photovoltaic) – Department of Infrastructure, Energy and Mobility of Grisons 2020

  • Publications
    Fotovoltaico: Sol’CH un progetto pilota in Valposchiavo – Il Bernina of 23.12.2021