Your Guide to Passivhaus: Comfort, Energy Efficiency, and Problem-Solving with Q50

Q50 supports homeowners, builders and retrofit professionals with independent testing and validation services that are central to achieving the Passivhaus (Passive House) standard. From airtightness to ventilation validation, Chris and the team provide reliable, NSAI-registered assessments across Ireland.  

Understanding Passivhaus 

Passivhaus is a rigorous building standard designed to deliver ultra-low energy use, excellent comfort and healthy indoor air quality. It is based on five core principles: 

• Continuous insulation without thermal bridges 

• Exceptional airtightness of the building envelope 

• High-performance windows and doors 

• Mechanical Ventilation with Heat Recovery (MVHR) 

• Optimised orientation and solar shading 

Whether in a new build or a deep retrofit, achieving these targets requires independent testing at key stages of the project. 

Why It Matters 

By designing and verifying a building to the Passivhaus standard, you can: 

• Cut heating and cooling demand by up to 90% compared with standard construction 

• Ensure constant indoor temperatures without draughts 

• Improve air quality and eliminate condensation risks 

• Reduce carbon emissions and future-proof your home 

Tips and Common Issues in Passivhaus Projects 

While the principles of Passivhaus are straightforward, the implementation can be tricky, and small mistakes often compromise performance. Some of the most common challenges we see include: 

• Air leaks at junctions – gaps around windows, doors, roof-wall connections, and service penetrations are frequent culprits. Even small leaks can significantly affect energy performance. 

• Poorly installed insulation – compressed or incomplete insulation can create thermal bridges, reducing efficiency and causing cold spots. 

• Incorrect MVHR-setup – improper commissioning of the ventilation system can lead to uneven airflow, excess humidity, or wasted energy. 

• Overheating in summer – Passivhaus homes are well-insulated, which is great in winter, but can trap heat in summer if shading or ventilation strategies are overlooked. 

• Retrofit complexities – older buildings often have hidden moisture issues, uneven walls, or structural constraints that make continuous insulation and airtightness difficult. 

Tips to avoid these issues: 

• Plan and test early – perform airtightness and ventilation checks during construction, not just at the end. 

• Pay close attention to junctions and transitions – use tapes, gaskets, and membranes correctly. 

• Commission ventilation systems carefully – follow manufacturer guidance and perform airflow validation. 

• Consider shading, window orientation, and ventilation paths to prevent summer overheating. 

• Use thermal imaging or drone surveys to spot hidden issues before they become expensive problems. 

• Work with experienced assessors – independent testing ensures compliance and prevents costly rework. 

These steps not only help meet the Passivhaus standard but also enhance comfort, air quality, and long-term energy savings. 

Q50’s Role in Passivhaus Projects 

Our calibrated equipment and experienced assessors provide the essential measurements that underpin Passivhaus certification, including: 

• Airtightness Testing (q₅₀ result) – to confirm compliance with Part L and SEAI grant requirements 

• Ventilation Validation – ensuring MVHR systems perform correctly and efficiently 

• Thermal Imaging & Surveys – detecting hidden leaks and thermal bridges before handover 

All services are delivered independently and in line with NSAI and SEAI standards, giving you confidence that your project truly meets the Passivhaus benchmark. 

 Contact Q50 today to discuss testing for your Passivhaus project or deep retrofit anywhere in Ireland.