Bolueta Tower of Bilbao: The tallest passivhaus in the world

Public nZEB buildings case study
Project type
New Construction

Bolueta Tower / © VArquitectos

The Bolueta Tower in Bilbao, Spain, occupies a significant historical plot, once home to the steel industry. Built between 2015 and 2018, its construction represents a transformation from industrial heritage to modern, eco-conscious urban living. The building stands as a remarkable feat of architectural and sustainable innovation. With a total height of 88 metres, it boasts 32 stories, with 28 of them above ground level. This makes it the tallest passivhaus building in the world, setting new standards for energy-efficient high-rises.

Designed by VArquitectos and built by contractor Sukia, the tower reflects a commitment to energy efficiency from its inception. It received the Passivhaus certificate in 2018. In fact, the Passive House Standard it adheres to already meets the European Union’s requirements for Nearly Zero-Energy Buildings.

The tower addresses social housing needs by providing 108 state-subsidised apartments and 63 homes for individuals with low incomes or specific social needs. Commissioned by the Government of the Basque Country through its public property development company, Visesa, this building represents an integration of sustainability, architectural innovation, and social responsibility.

How was this building procured?

The project was initiated by the Basque Government through its public property development company, Visesa. In 2011, Visesa held a competition to procure the services for drafting the building project and overseeing the works of the Bolueta Tower. The Government set high standards for the building’s energy performance and awarded the project to a team of architects and builders who could meet these requirements. This competition was won by the architectural firm VArquitectos.

Initially, the project envisioned a district heating centre, but it was deemed unfeasible. It was at this point that the architects proposed the possibility of adapting the project to the Passivhaus standard. Upon confirmation of its feasibility, the property owner, Visesa, granted their approval to VArquitectos.

The project had a total cost of EUR 14.5 million. Despite the passivhaus-related modifications and additions to the project, which resulted in a 3% increase in the construction budget, the overall efficiency was boosted by 80%. The total cost, nevertheless, remained within the typical price range per square metre for subsidised housing in the Basque Country.

The project was carried out through a public procurement process that prioritised energy efficiency and sustainability.

What are the key nZEB features?

The building’s envelope is designed to provide excellent insulation and airtightness, while a heat recovery ventilation system ensures that fresh air is continuously circulated. Bolueta’s HVAC demand of just 5.7 kWh/m2  represents an 80% reduction compared to a baseline building. Among the individual features of the building, the following ones stand out:

  • The tower is equipped with triple-glazed windows;
  • The exterior façade of the structure is covered with nearly 3,000 double-layered trays of aluminium composite. To ensure the mitigation of thermal bridges and the optimisation of insulation, the tower incorporates stone wool insulation provided by Rockwool. This makes the tower an almost totally hermetic box;
  • Natural materials such as wood are used in interiors, which provide high levels of energy performance;
  • The tower incorporates an internal air renewal system, eliminating the necessity of opening windows for ventilation. This system effectively safeguards against the intrusion of undesirable odours and dust particles into the living areas while ensuring a stable indoor temperature;
  • The orientation of the building and the placement of the different materials in the construction aim to maximise energy efficiency;

Did the project have an impact on skills?

The Bolueta Tower is the highest passivhaus building in the world. Such a feat required the development of new approaches that helped to promote nZEB construction. The building’s unique design and technical requirements necessitated specialised knowledge and skills, starting from the planning stage and throughout the whole construction process into the maintenance phase. The construction of this first-of-its-kind tower in the immediate vicinity has set a precedent for further developments in the area.

Keywords: Nearly Zero-Energy Building (nZEB), Skills Development, Social Housing, High-rise, Tower, Passivhaus, Bilbao, Basque Country, Spain.

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