ISO 52000-3:2023

Overview

ISO 52000-3:2023 - “Energy performance of buildings - Overarching EPB assessment - Part 3” provides a transparent, structured framework for determining and reporting Primary Energy Factors (PEF) and CO2 emission coefficients for energy delivered to and exported from buildings. Designed to complement ISO 52000-1, this standard specifies the choices, conventions and reporting requirements needed to complete energy performance of buildings (EPB) calculations. It focuses on PEF and CO2 parameters only and explicitly excludes unrelated environmental impacts (e.g., nuclear waste, particulate matter, deforestation).

Key topics and technical requirements

ISO 52000-3 organizes the technical approach and reporting around clearly defined choices and conventions. Major topics include:

• Definitions and symbols - standardized terms (primary energy, energy carrier, PEF, CO2 emission coefficient) to ensure consistency in EPB assessments.
• Assessment boundary and origin of energy - guidance on how to define the geographical and system perimeter for delivered and exported energy.
• Accounting methods - conventions for allocating primary energy and emissions, including differences allowed between delivered and exported energy PEFs.
• Calculation conventions:
  • Time resolution and data sources (time horizon)
  • Use of Net Calorific Value (NCV) or Gross Calorific Value (GCV)
• Data choices and conversions:
  • Energy sources to include (available carriers)
  • Types of CO2 emission coefficients (scope and inclusion of GHG equivalents)
  • Conventions for energy conversion and for exported energy treatment
• Assessment methodologies:
  • Treatment of energy exchanges between geographical perimeters
  • Multisource generation mix calculations
  • Allocation for multi-energy output systems and optional life cycle approaches
• Reporting template - Annex A provides a normative template to report the choices made, ensuring transparency and reproducibility. Annexes B and C give examples and additional explanatory material.

Practical applications and users

ISO 52000-3 is aimed at anyone who needs robust, comparable PEF and CO2 inputs for building energy assessments:

• National authorities and regulators setting or harmonizing EPB rules and default factors
• Standards experts and technical committees developing national/sectoral PEF datasets
• Energy modelers, building designers and consultants performing EPB calculations and certifications
• Certification schemes and auditors that require traceable PEF/CO2 inputs for compliance or reporting

Use cases include EPB compliance reporting, building design optimization, life-cycle energy accounting, and evaluating exported energy flows (e.g., on-site PV export).

Related standards

• ISO 52000-1:2017 - Overarching EPB assessment: general framework and procedures (normative reference)
• ISO 7345 - Thermal performance of buildings: physical quantities and definitions (normative reference)

Keywords: ISO 52000-3, PEF, primary energy factor, CO2 emission coefficient, energy performance of buildings, EPB assessment, delivered energy, exported energy, building energy certification.