Driven by the rapid growth of AI and digital services, data centers now consume roughly 3% of Europe’s total energy, prompting the European Commission to mandate energy reporting under the Energy Efficiency Directive (EED). To address initial data gaps and alignment challenges, the HEATWISE project establishes a unified KPI framework that links server room thermal design to energy efficiency and waste heat recovery. This framework bridges the gap between technical performance and regulatory compliance, specifically addressing potential calculation conflicts between traditional Power Usage Effectiveness (PUE) and modern waste heat reuse.

To validate this framework, the thermal and EED-aligned KPIs were implemented into an open-source Computational Fluid Dynamics (CFD) simulation. By calculating performance indicators directly at the server inlets, the tool successfully captures localized efficiency losses, such as cold air bypass and hot air recirculation. Ultimately, this integration allows data center operators to optimize day-to-day cooling and thermal performance while seamlessly fulfilling their EU reporting obligations.