The new replacement building, centrally located in Affoltern am Albis, is a compact three-storey residential building with a top floor that...
Project by Viridén + Partner AG in Seewadelstrasse
Architect Karl Viridén
``Today, we can offer a wide range of colours and shapes of innovative photovoltaic modules for glass facades.``
Active glass facade

The new replacement building, centrally located in Affoltern am Albis, is a compact three-storey residential building with a top floor that recedes on three sides. By building according to the Minergie-P-Eco standard, the residents of the fourteen flats benefit from a building that was realised with ecological, sustainable materials and features low-radiation interiors. The innovative solar power-producing glass facade and the PV installation on the roof make the building a plus-energy house. In addition, there are connections for electric cars and the installation of a storage battery has already been planned.

First and second storey floor plan with two 2-room apartments and two 4.5-room apartments. Source: Viridén + Partner AG.

The balconies on the south-east facade are also equipped with PV modules and are intended to be perceived as part of the overall volume.

Changing colour at the building corner, there is no indication that this facade also produces electricity.

Building characteristics
  • Building typology
  • Construction type
  • Year of construction
    From May 2018 to September 2019
  • Energy reference surface
    1395 m²
  • Energy index
    14.5 kWh/m²a (heating and electricity)
  • Energy labelling
Architect Karl Viridén
``The focus is on the active glass facade, which is a step forward both technically and aesthetically.``
Active solar surface 153m² 688m²
Active solar surface ratio >75% 72%
Peak power 31 kWp 85 kWp
Building skin application Flat roof Cold facade
Storage Under consideration
Energy production
Source: Viridén + Partner AG
Not available
Building skin
  • Application
    Standard modules are laid on a metallic support system.
  • Description
    Flat roof insulated with mineral wool.
  • U value
    0.08 W/m²K
  • Fastening system
  • Other

On the flat roof was installed an applied photovoltaic system.

  • Application
    PV cladding integrated in a cold facade
  • Description
    Light-weight timber frame insulated with glass wool.
  • U value
    0.10 W/m²K
  • Fastening system
    Continuous fixing system (EcoLite substructure)
  • Other
    The Swiss Federal Office of Energy supported this new type of installation (pre-fabrication) through a pilot and demonstration project.

The substructure must be built at level with the wind protection layer.

As part of a federal P+D project, it has even been requested that part of the substructure be pre-assembled in the timber construction company’s production hall on a trial basis.

  • Application
  • Description
    Triple glazing with wooden frame
  • U value
    0.80 W/m²K

All building facades including balcony parapets are to be clad with PV modules.

BIPV module
  • Product
    Custom made
  • Manufacturer
    KIOTO Photovoltaics GmbH
  • Cell technology
  • Front glass type/customization
    4mm TVG front glass textured (Rosa504clear) with digital ceramic print
  • Cell colour
  • Dimensions
    Custom made
  • Specific power
Technical details

The building is a hybrid construction. This means that the load-bearing walls, the intermediate slabs and the staircase core are made of concrete while the outer walls, the roof area and partly the inner walls are made of wood. The timber structure of this new replacement building is covered with PV modules installed as a rear-ventilated facade. The south-west façade (front) was assembled as a pilot and demonstration project to test a new type of installation. The prefabrication of the facade cladding was boosted by having windows, window frames and the substructure for the glass facade modules already assembled in a workshop.

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Vertical section
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  • Total cost of the building
  • Square meter price
    Approx. 1520 CHF/m² (facade cost considering materials and electrical components)
    The cost of the facade is not representative of the current BIPV market as it is a constructive element which was developed specifically within the “Pilot, demonstration and flagship project” of the Swiss Federal Office of Energy.

The PV facade was designed by Ernst Schweizer AG.

Parties involved
  • Owner
    Private owner
  • Architect
    Viridén + Partner AG
  • Substructure system
    Ecolite AG
  • Photovoltaic Installer
    Ernst Schweizer AG
  • Photo
    Peter Schäublin, ©Ernst Schweizer AG.
Awards and recognitions
  • Awards
  • Publications
  • Other
    The Federal Office of Energy (SFOE) has financially supported this project (P+D).