This document provides a recommended future standard for interoperability between the ERC DLL and AHU software to implement the provisions of EN 308:2022 and expected new Ecodesign requirements in air handling unit selection calculations with respect to internal leakage and moisture recovery. It specifies the principles of data exchange at the interface between the AHU and ERC software to account for the impact of internal leakage on AHU performance. The document also comments on the implementation of ERC DLL outputs in AHU calculations. To complement the main subject of the document, Appendix A lists other relevant and recommended DLL outputs and Appendix B provides the ventilation air terminology.