Initial findings of the Zero Caron Hub's Design and as-Built Performance research

Download the full interim report / executive summary and appendices here.

Nothing surprising so far; with the following issues identified:

1. lack of suitable energy performance analysis tools
2. SAP needs further work: concern about input assumptions and transparency of inputs. Further work for certain inputs required, including ventilation, thermal mass, hot water + lighting
3. lack of communication between design team and 'energy assessor' 
4. lack of understanding by contractor, planners about their role in building energy performance.
5. lack of clarity and consistency on what planning requirements are needed and information required to demonstrate compliance.
6. product and material specifications are tested according to EU norms in isolation (like thermal labs and as components) rather than in in-situ systems and this may contribute to a performance gap.
7. limitations of U-value calculation conventions and comparison with in-situ testing methodology are an issue
8. practice of substitution of 'or equivalent' specifications requires sufficient information on performance criteria of products or materials so that an 'equivalent' substitute is made. Often this is not the case and changes not fed back to the design team and to performance assessor.
9. insufficient detail/drawings (or unbuildable details drawn) for the construction team to construct assemblies to achieve intended performance such as airtightness and thermal performance. No feedback from site to design team to learn lessons.
10. limited installation/construction instructions provided by manufacturers on their materials
11. lack of skills/knowledge on site to install systems correctly, especially ventilation systems and heat pumps
12. priority of Building Control on health & safety and they are often sen as "quality Control', when compliance is still the responsibility of the contractor
13. Accredited and Enhanced Construction Details are being reviewed as well as thermal bridge calculation procedures and need to be updated to reflect improved building fabric standards, buildability and robustness
14. lack of a Competent Person Scheme for thermal bridge calculations
15. lack of knowledge and skills to deliver building performance at all levels are a concern

In the report, a 2020 ambition was highlighted: to demonstrate that "at least 90% of all new homes meet or perform better than the 
designed energy / carbon performance".

A final report will be issued in March 2014.