The definition of ‘meaningful reduction’ is context specific. The required reduction in active cooling demand or CO2 emissions are not specified in the criteria as this is specific to each project. To demonstrate a meaningful reduction, the passive design analysis must show that:
– A rigorous and pragmatic approach was taken in selecting the most suitable strategies / technologies
– The strategies sought to maximise the potential for reduction in energy consumption, taking into account technical and site constraints
As the potential for reduction is context specific, the assessor’s judgement can determine whether a ‘meaningful reduction’ has been achieved. For instance:
Scenario 1: Assessment has multiple site constraints which result in a 2% reduction in CO2 emissions. The assessor is satisfied that the design team have made a significant effort to maximise the potential for reduction having considered technical and site constraints. This would be considered a meaningful reduction.
Scenario 2: The passive design analysis has highlighted a potential for significant reduction with LZCs, however many of these technologies were discounted due to capital cost considerations. The resulting building achieves a 6% reduction in CO2 emissions, however the actual potential was significantly higher. This would not be considered a meaningful reduction.
