Greenpeace’s Brussels headquarters: a reused factory with fresh air
In the dense urban fabric of central Brussels, the new Greenpeace Belgium headquarters occupies a surprising setting: a former organ factory hidden inside the block. The existing buildings – including the old Manufacture d’Orgues de Bruxelles – have been carefully transformed by architecture office archipelago into a contemporary, flexible workspace of around 2,300 m². Rather than building new, the client chose architectural reuse as the starting point. The result is a layered ensemble of row houses, workshop spaces and in-between courtyards that now host offices, meeting rooms, guest rooms and activist workshop areas – all geared towards Greenpeace’s mission and way of working.
Visit a reference projectSolution
Hybrid Ventilation , Solar Shading
Location
Bruxelles, Belgium
Sector
Commercial Buildings
Project Type
Refurbishment
Project partners
archipelagoA HQ aligned with Greenpeace values
From the beginning, the project brief was about more than creating functional office space. The building had to reflect Greenpeace’s environmental values in its design and operation:
- Re-use before new build, keeping as much of the existing structure as possible
- Low-energy operation, with reduced CO₂ emissions over the full life cycle
- A healthy indoor climate that supports focused work, collaboration and activism
- Flexible spaces that can adapt to different activities over time
To support these ambitions, the design team placed strong emphasis on ventilation and indoor air quality. Ventilation is monitored space by space to match different usage patterns, while avoiding large ventilation shafts and heavy structural interventions in the existing fabric.
In this context, a conventional, fully mechanical HVAC solution would have contradicted both the spatial and environmental goals. Instead, the team looked for a hybrid ventilation strategy that could combine natural airflow with targeted mechanical support.
Hybrid ventilation: the optimal choice
Hybrid ventilation – also known as mixed-mode ventilation – combines natural ventilation through windows and openings with more traditional mechanical systems. The intention is to use fresh outside air whenever conditions allow and only rely on fans and ducts when necessary, thereby reducing energy consumption while improving comfort and air quality. This approach was a natural match for Greenpeace HQ because: • The building consists of different volumes and room types – from open offices to enclosed meeting rooms and workshop spaces – each with its own ventilation needs. • The reuse concept favours minimal additional shafts and technical spaces. • Greenpeace wanted direct access to fresh air, openable façades and the possibility for night-time cooling. To meet these requirements, WindowMaster delivered a hybrid ventilation solution built around NV Embedded®, integrating natural ventilation, solar shading and mechanical components into one coherent control strategy.
The control system: NV Embedded® at the core
At the heart of the Greenpeace HQ indoor climate concept is NV Embedded®, WindowMaster’s scalable control system for natural and hybrid ventilation. NV Embedded® continuously monitors both indoor and outdoor conditions, adjusts the amount of ventilation and keeps the indoor climate within comfortable limits – while also being able to integrate shading, heating, cooling and smoke control where required.
For Greenpeace Belgium HQ, the indoor climate strategy includes:
- Hybrid ventilation control across selected zones
- Automated façade windows equipped with 40 WMX 804-2 chain actuators
- Control of motorised variable air volume (VAV) dampers in the mechanical system
- Integrated control of 24 external sunshades
- Control of three VELUX INTEGRA® skylights
- Operation based on real-time input from indoor sensors and outdoor LUX- and weather data sensors
By combining window automation, VAV control and solar shading under NV Embedded®, the building gains a coherent indoor climate strategy instead of several isolated systems.
How the hybrid ventilation solution works
In daily operation, the system supports different climate modes throughout the year:
- On mild days, natural ventilation dominates. Automated windows open to bring in fresh air based on indoor CO₂ levels, temperature and outside conditions such as wind speed and outdoor temperature.
- When internal heat gains rise or weather conditions are less favourable, mechanical ventilation takes over more of the load, with the motorised VAV dampers regulating air volumes room by room.
- During cooler nights in warmer periods, the system can enable night-time cooling, flushing warm air out of the building so that the exposed structure can absorb heat gains the next day.
At the same time, NV Embedded® coordinates solar shading and daylight:
- The 24 external sunshades and the VELUX INTEGRA® skylights are adjusted in relation to daylight levels and solar gains, based on data from outdoor LUX sensors.
- When solar radiation is high, the shading limits overheating and glare, reducing the need for active cooling.
- When conditions allow, the shading opens to maximise daylight, reducing the demand for artificial lighting and maintaining visual comfort at workstations.
All of this happens largely in the background, so building users can concentrate on their work while the system maintains a stable, pleasant indoor environment.
The integrated WindowMaster solution supports the wider goals of the project
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Healthy indoor climate
Continuous monitoring of CO₂ and temperature ensures that office and meeting spaces receive the right amount of fresh air. Natural airflow, when available, creates a more direct connection to the outside environment.
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Energy-efficient operation
Hybrid ventilation reduces the running time of mechanical systems, cutting energy use and associated CO₂ emissions. Coordinated shading helps mitigate overheating and limits cooling demand.
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Respect for existing architecture
Compact, surface-mounted actuators minimise the visual impact on the reused façades and window frames. The system reduces the need for additional ducts and shafts, preserving the character of the former organ workshop.
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Flexibility for changing uses
Because ventilation is monitored and managed per room or zone, spaces can be assigned to different activities without fundamental changes to the infrastructure.
A workplace that practices what it preaches
The transformation of the old organ atelier into the Greenpeace Belgium HQ shows how reuse, energy efficiency and a healthy indoor climate can reinforce one another rather than compete. By combining hybrid ventilation, intelligent window automation, solar shading and VAV control under one NV Embedded® platform, the indoor climate solution helps the building deliver comfortable, adaptable workspaces with a lower environmental impact.
“This project is a good example of how we can support ambitious clients with a clear environmental agenda. At Greenpeace Belgium HQ, hybrid ventilation and coordinated sun shading help create an energy-efficient, comfortable indoor climate – in a building that has already saved a lot of resources simply by being reused instead of rebuilt. In this way, the project contributes to our purpose: to create a better world where every person has fresh air indoors and a safe built environment.”
Jannick Roth
Building Performance & Standardization Manager