From the overview of the state of the art, it is clear that the issues raised in the previous section can’t be solved directly from existing knowledge. Partial answers to each of these issues are available, but a new annex is needed to address the gaps and integrate the available solutions in a coherent and operable rating method.

International collaboration is a prerequisite for this effort since market access for innovative IAQ management strategies is currently blocked in many countries due to all kinds of prescriptive regulatory constraints. With the methods developed in the annex, we will be able to generate the necessary body of evidence to take regulatory action to overcome these barriers, generate consensus, open these markets and create a level playing field, which today is limited by very sparse and inconsistent approaches in the different member states.