In this article, the author Gioia Salvatori examines how Europe’s fragmented landscape of energy‑efficiency data is hindering effective policymaking. She highlights how inconsistent definitions, incompatible indicators and uneven data availability across Member States create a 'Babel' of information that complicates comparisons, slows down progress and ultimately weakens the EU’s ability to design targeted, evidence‑based measures to reduce energy demand.

Salvatori also explores the work of the IEPB project, which aims to harmonise methodologies and build a more coherent framework for assessing energy‑efficiency performance across Europe. By improving data quality, strengthening comparability and fostering collaboration between national authorities, the project seeks to support more transparent monitoring and more effective policy design. The article ultimately argues that without a shared language and consistent metrics, Europe risks losing momentum in its energy‑efficiency ambitions — and that harmonisation is a crucial step toward a more resilient, climate‑aligned future.