Beyond the Label: The Sufficiency Approach Transforms EPDs from an Impact Measurement Tool to Critical Decision-Making Tool for Sustainable Design

This study situates Environmental Product Declarations (EPDs) within the broader challenge of decarbonising the built environment, arguing that efficiency-oriented approaches remain insufficient unless complemented by a sufficiency paradigm that already questions “how much is necessary” in the meta-design phase. Building on an interdisciplinary reading of standards and the scientific literature, the paper analyses the regulatory architecture of Type III environmental declarations and discusses the operational implications of the two main reference frameworks for construction EPDs—ISO 21930 (global) and EN 15804 (European)—with attention paid to methodological rigidity, system boundaries, and the granularity of climate-related indicators. The paper highlights that the declared aim of comparability is frequently undermined in practice by heterogeneous Product Category Rules, background databases, modelling assumptions, and verification practices, producing an “illusion of comparability” and limiting the reliability of product-to-product comparisons. Emphasis is placed on the epistemic role of the functional unit and reference service life, showing how narrowly product-based units can conceal system-level effects and bias decision-making. The paper concludes that EPDs are most effective when interpreted as boundary objects linking policy, industry, and design, and when embedded in a sufficiency-oriented “critical ecology of materials” that integrates embodied and operational carbon within contextualised project decisions.