New UK Standard for Carbon-Free Buildings Unveiled

The long-awaited pilot version of the UK Net Zero Carbon Buildings Standard (UKNZCBS) has finally been released, marking a significant milestone in the UK Built Environment Industry. This collaborative effort from experts aims to provide a robust framework for proving that built assets are truly net zero carbon, aligning with the nation’s ambitious climate targets.

One of the key advocates for this new standard is the Passivhaus Trust, which has praised the targets and methodology proposed in the UKNZCBS. In fact, they note that these closely align with the operational and renewable energy generation targets of the Passivhaus Plus standard. This alignment not only helps in achieving net zero carbon objectives but also ensures a healthy and comfortable living environment for occupants.

Sarah Lewis, the research & policy director at the Passivhaus Trust, emphasises the effectiveness of the Passivhaus Plus standard in meeting the operational carbon performance required by the UKNZCBS. She points out that this approach addresses crucial aspects like indoor air quality, overheating, and occupant comfort in addition to energy efficiency.

Furthermore, the Passivhaus Trust appreciates the UKNZCBS’s focus on actual as-built performance rather than solely relying on design intent, as seen in current Building Regulations. This shift is expected to reduce the notorious “performance gap” in the industry, where actual energy use often exceeds design predictions by a significant margin.

Research indicates that this performance gap can lead to a 60% increase in energy use compared to initial estimates, and sometimes even up to 200%. By embracing the Passivhaus quality assurance process, there is greater certainty in achieving desired outcomes across health, comfort, and net zero carbon targets, ultimately reducing the risk of underperformance in post-completion testing.

On the front of embodied carbon, the Passivhaus Trust highlights studies demonstrating that designs optimised for Passivhaus performance can also contribute to lower embodied carbon emissions. By focusing on improved form factors, structural and cladding requirements can be minimised, along with a reduction in insulation volume. The Trust underscores the role of good Passivhaus design in assisting projects to meet the embodied carbon targets set forth in the UKNZCBS.