Revolutionising Green Design: MosArt Wins Sustainable Building of the Year for Ireland’s First Passive House Office

MosArt is proud to announce that Senan House, Ireland’s first Passive House office building, has been recognised with the prestigious Sustainable Building of the Year award. This accolade is a testament to the innovative design and forward-thinking sustainable practices that have become synonymous with MosArt. The project not only sets new benchmarks for sustainable architecture but also highlights MosArt’s commitment to leading the industry towards a future of high-performance, eco-friendly buildings.

A Milestone in Sustainable Office Architecture

Located within the Enniscorthy Technology Park, Senan House stands as a pioneering example of what is achievable in modern office architecture when sustainability is placed at the core of the design process. As the first office building in Ireland certified to the internationally recognised Passive House (PH) standard, Senan House delivers unmatched energy efficiency, thermal comfort, and indoor air quality.

The building was designed using a 'fabric-first' approach, ensuring that energy efficiency is prioritised at every stage. This method reduces the reliance on complex mechanical systems by focusing on the performance of the building envelope. From minimising thermal bridges to achieving superior airtightness, every aspect of the building’s design was meticulously planned and executed to ensure it performs far beyond traditional standards.

Key Features of Senan House’s Passive House Design

Achieving Passive House certification for an office building presented unique challenges. Office environments typically generate internal heat loads from equipment, lighting, and occupants, which can lead to discomfort if not managed effectively. MosArt tackled these challenges head-on, incorporating advanced design strategies and innovative technologies to ensure that Senan House meets the highest standards of energy efficiency, occupant comfort, and operational performance.

Some of the building’s standout features include:

• Exceptional Airtightness: Senan House achieved an impressive airtightness level of 0.15 air changes per hour (ACH), significantly surpassing the Passive House requirement of 0.6 ACH. This level of airtightness ensures that energy loss through the building fabric is minimised, enhancing both energy efficiency and indoor comfort.

• Thermal Bridge Elimination: A key innovation in the construction of Senan House was the elimination of thermal bridging—a common cause of energy loss. MosArt employed a range of advanced techniques, including the use of fibreglass reinforcement in place of steel re-bars and carefully offsetting the external wall panels from the steel structure. These efforts ensured that the building envelope maintains continuous insulation and airtightness throughout.

• Mechanical Ventilation with Heat Recovery (MVHR): The building’s MVHR system provides continuous fresh air while recovering up to 90% of the heat from outgoing air. This not only ensures a healthy indoor environment but also reduces the building’s energy demand for heating and cooling. The system is optimised using cloud-based technology for remote monitoring and control.

• On-Site Renewable Energy: Solar photovoltaic (PV) panels on the building’s roof generate an average of 44,386 kWh of electricity per year, with 48.2 kW peak power. The majority of the electricity produced is consumed on-site, with excess energy exported back to the grid, contributing to the building’s nearly zero-energy footprint.

Low Carbon Design

Sustainability is not only measured by operational energy efficiency but also by the carbon emissions associated with the building’s construction. Senan House sets a new standard in this regard by achieving embodied carbon levels of 434 kg CO₂e/m², well below the Royal Institute of Architects of Ireland (RIAI)’s 750 kg CO₂e/m² standard for office buildings. This low-carbon achievement was supported by the use of innovative construction methods, including factory-fabricated timber wall panels filled with cellulose insulation and the minimisation of steel in concrete slabs.

Additionally, Senan House promotes sustainable urbanism through its design. A pedestrian and cyclist bridge spans the River Slaney, linking the office to Enniscorthy’s town centre, while on-site amenities include 61 bicycle stands, 49 electric vehicle charging points, and shower facilities to support active and low-carbon commuting options.

Redefining Office Comfort

One of the most significant advantages of Passive House buildings is the enhanced level of comfort they offer to occupants. In Senan House, advanced building modelling ensured that temperature fluctuations and radiant discomfort were minimised, even in workspaces located near the extensive glazed facades.

The building’s ventilation system further contributes to a superior working environment by filtering incoming air through Fine Grade F7 filters, which are more efficient than the G4 filters typically used in NZEB buildings. This attention to indoor air quality ensures a healthier environment for building occupants, making Senan House not just energy-efficient but also a comfortable and pleasant place to work.

Challenges Overcome

Building to the Passive House standard for an office of this scale came with its own set of challenges. The sloping site required innovative solutions to manage access and drainage, while the strict requirements for airtightness demanded rigorous testing and careful detailing. MosArt's experience in Passive House design ensured that these challenges were not only met but that they provided opportunities for further innovation.

Additionally, the use of factory-fabricated timber wall panels, combined with advanced materials like fibreglass reinforcement in the concrete slabs, allowed for a reduction in both construction time and carbon emissions, proving that sustainability can be achieved without compromising on quality or efficiency.

International Recognition

Senan House has garnered international attention for its exemplary performance in sustainable office design. Scott Foster, former Director of Sustainable Energy at the United Nations, praised the building as a "landmark" for its near-zero emissions and resilience. This recognition underscores the global relevance of Passive House principles in addressing climate change and highlights MosArt’s role as a leader in sustainable design.

A Future-Ready Office Building

Senan House represents a bold step forward in the evolution of office design in Ireland. By achieving Passive House certification, the building sets a new benchmark for energy efficiency, indoor comfort, and low-carbon construction. The recognition of Senan House with the Sustainable Building of the Year award is a validation of MosArt’s commitment to pushing the boundaries of sustainable architecture.

As the first of its kind in Ireland, Senan House serves as a model for future developments, proving that high-performance, energy-efficient office buildings are not only possible but essential in meeting the challenges of climate change and ensuring a sustainable future for generations to come.