Projects

23.07.2026

Isa Zanetti

Prova Project

Location

Basel, Switzerland

Herzog & de Meuron

Year

2025

Hortus is an energy-positive office building in Basel designed by Herzog & de Meuron as a fully integrated system combining architecture, materials, and energy strategies. The project is based on a compact timber structure with low embodied carbon and a holistic design approach aimed at minimizing lifecycle impacts.

Awards

Project description and press material by Herzog & de Meuron.

Interior view highlighting the exposed

Building characteristics

Building typology

Office building


Type of intervention

Office building


Building use

Office building


Building area

14.100 m²


Energy performance

Hortus achieves zero operational carbon emissions, with an energy demand of approximately 33 kWh/m²·year and on-site renewable production of around 66 kWh/m²·year, generating a surplus of energy over its operational needs.


Energy standard

Not disclosed

A regenerative office building in Basel

Hortus is an energy-positive office building in Basel designed by Herzog & de Meuron as a fully integrated system combining architecture, materials, and energy strategies. The project is based on a compact timber structure with low embodied carbon and a holistic design approach aimed at minimizing lifecycle impacts. Photovoltaic systems are deployed across the building, combining a large rooftop installation with additional integration along the parapets, enabling on-site renewable energy production that exceeds operational demand. In this sense, Hortus can be described as regenerative, as it generates a surplus of energy and offsets its embodied energy over time.


Hortus is an energy-positive office building in Basel designed by Herzog & de Meuron as a fully integrated system combining architecture, materials, and energy strategies
Herzog & de Meuron
Architett
Interior view highlighting the exposed
Interior view highlighting the exposed

Energy

Building skin application

Rooftop PV is applied (BAPV), complemented by integration along the parapets

Nominal power

Not disclosed (approx. 1 MWp estimated based on available PV surface)

Active solar surface

5.000 m² (roof + parapets)

Energy production

Source: 66 kWh/m²·year (SIA reference area)
0 kWh

Self-Consumption

Partial self-consumption with significant surplus energy exported
50%

Self-Sufficient

Partial self-consumption with significant surplus energy exported
30%

Building skin

The building envelope of Hortus is conceived as a modular and material-efficient system integrated within the overall timber structure. A regular structural grid defines the facade rhythm, combining repetitive window elements with a layered construction based on timber, cellulose insulation, and natural finishes. This approach ensures high thermal performance while maintaining a reduced palette of renewable materials.

BIPV module

The photovoltaic system is documented at a system level (surface and energy performance), while detailed module specifications are not publicly available.

Roof

Flat roof integrated within a timber structural system, with layered insulation and a large-scale photovoltaic installation covering most of the roof surface

Facade

Layered facade system based on a modular timber structure with insulation (likely cellulose) and repetitive window openings; photovoltaic elements are selectively integrated along the parapets

Glass surface

High-performance glazing system integrated within a timber facade; likely triple glazing with wooden frames (consistent with building concept)

Title open

High-performance glazing system integrated within a timber facade; likely triple glazing with wooden frames (consistent with building concept)

Interior view highlighting the exposed
Interior view highlighting the exposed
Interior view highlighting the exposed

Technical details

Vertical section

The building envelope of Hortus is conceived as a modular and material-efficient system integrated within the overall timber structure.

Horizontal section

The building envelope of Hortus is conceived as a modular and material-efficient system integrated within the overall timber structure.

Parties involved

Client

Senn Resources AG

PV consultant

Planeco GmbH

PV installer

Planeco GmbH

Facade consultant

Christoph Etter Fassadenplanungen

Other professionals

Planeco GmbH

Credits

Photo

© Maris Mezulis

Video

© Maris Mezulis

Technical drawings

© Herzog & de Meuron