As the push for net zero buildings gains momentum, accurately measuring and understanding how buildings perform in practice becomes crucial. Achieving net zero emissions isn’t just about theoretical models; it’s about real-world performance. This increasing focus on actual building performance opens numerous opportunities for energy assessors, retrofit assessors, and surveyors.
What is Building Performance Measurement?
Building performance measurement involves assessing a building’s actual performance to ensure it aligns with its designed or assumed performance. It encompasses various factors such as fabric thermal performance, airtightness, heating and ventilation systems, energy use, overheating, and householder experience. These metrics are essential for ensuring the quality of construction and optimising in-use energy efficiency, comfort, and usability.
Key Aspects of Building Performance Measurement
There are several critical aspects of building performance that can be measured:
- Airtightness: Widely used since 2007 for new builds and increasingly for retrofit projects, airtightness tests measure how well a building prevents air leakage.
- Heat Transfer Coefficient (HTC): This measures the overall thermal efficiency of a building, providing insights into heat loss and comparing it to the original design intent.
- In-situ U-values: These assess the thermal performance of individual elements such as floors, walls, ceilings, and windows.
These metrics are crucial inputs for modelling tools and Dynamic Simulation Models, helping to update energy models and understand actual building performance.
Building Performance Evaluation
Building performance evaluation involves integrating various performance measurements and other insights to develop a comprehensive understanding of a building. In addition to measuring HTC, airtightness, and U-values, qualitative assessments like Post Occupancy Evaluation surveys and thermal imaging can be conducted. Combining these insights helps determine whether a building’s underperformance is due to construction issues, building services setup, or occupancy behaviours.
The Importance of Building Performance Measurement
For energy assessors and retrofit assessors, investing in the ability to carry out building performance measurements offers significant benefits:
- Enhanced Services: Adding measurement-related services can provide additional revenue streams and greater value and insight for clients.
- Accurate Assessments: Measurement tools and techniques allow for more precise and non-invasive evaluations of building performance.
- Policy Alignment: Staying ahead of policy changes and industry trends ensures that practitioners can meet evolving standards and client expectations.
Policy Changes Influencing Measurement Services
Several policy changes and consultations are set to increase the demand for building performance measurement services:
- Future Homes Standard (2026): Proposes testing real-world energy performance against modelled performance for new builds.
- ECO4: Potentially introducing a ‘pay for performance’ mechanism, allowing measured HTCs to determine the uplift awarded on ECO-backed projects.
- PAS 2035: Expected to see a greater call for measurement and evaluations under this standard and other government-backed schemes.
Upcoming Developments to Watch
Several key developments in the building performance measurement field include:
- Measured Energy Performance: The launch of competency schemes for measured HTC.
- RdSAP 10: Anticipated for Summer 2024, including the ability to input measured airtightness.
- DESNZ Consultation: Involving ECO4 and the Great British Insulation Scheme (GBIS) Pay for Performance.
- Future Homes Standard/HEM Response: Adopting HTC in-situ measurement for new builds from 2026.
Conclusion
The shift towards net zero buildings underscores the importance of measuring and understanding actual building performance. For energy assessors, retrofit assessors, and surveyors, this presents an array of opportunities to enhance services, provide accurate assessments, and align with evolving policy standards. By embracing building performance measurement, professionals can contribute significantly to achieving sustainable, energy-efficient buildings in practice, not just in theory.
