New Guide: Using EN ISO 52120-1 to Turn Sustainability Goals into Building Performance You Can Prove
eu.bac and REHVA have jointly published a new guide on EN ISO 52120-1: a practical framework that helps building owners, facility managers, engineers, and ESG teams translate broad sustainability and policy ambitions into concrete automation requirements and measurable, verifiable performance.
Why we published this guide
Sustainability goals have never been more clearly defined. The EU’s climate targets are set. CSRD reporting is live. The EPBD is tightening requirements on building automation year by year. The EU Taxonomy is tying green finance to verified performance criteria.
And yet, for many organisations managing buildings, the gap between policy language and on-the-ground implementation remains wide. What does it actually mean to have an “energy-efficient building”? How do you specify it in a tender? How do you prove it to an auditor, a tenant, or an investor?
That is the gap this guide is designed to close.
What EN ISO 52120-1 does
EN ISO 52120-1 is an internationally recognised standard that classifies building automation and control systems (BACS) into performance classes — A, B, and C. Each class has a precise, auditable list of required functions across heating, cooling, ventilation, lighting, shading, and more.
This classification system turns ambition into specification: rather than aspiring to a “sustainable building,” an owner can write into their project brief: “We require Class A building automation per EN ISO 52120-1.” Every engineer, HVAC contractor, and system integrator on the project then has a concrete checklist. There is no ambiguity about what is expected, and there is a clear basis for verification once the building is commissioned.
Why this matters right now
Three regulatory drivers make EN ISO 52120-1 particularly timely. The Corporate Sustainability Reporting Directive (CSRD) requires large EU companies to report on building performance from financial year 2024 onwards; a Class A building generates that data automatically and in an auditable format. The Energy Performance of Buildings Directive (EPBD) already mandates automated control systems in large non-residential buildings, with thresholds tightening progressively through 2030 to cover most of the commercial building stock. And the EU Taxonomy ties access to green finance to verified performance criteria, meaning buildings that cannot demonstrate compliance risk losing both value and investor appeal. EN ISO 52120-1 provides a single, coherent framework for meeting and evidencing all three.
With EN ISO 52120-1, you can specify it, verify it & prove it
The core value of the standard lies in three interconnected capabilities it gives building owners and operators.
Specification clarity. Stating a required automation class in a tender or project brief removes ambiguity for the entire supply chain. It gives all parties — HVAC engineers, control suppliers, system integrators — a shared reference point and a concrete performance target.
Post-installation verification. Because each class comes with a defined function list, it is straightforward to audit whether the building actually delivers what was specified. Were CO₂ sensors installed and linked to the ventilation system? Are trend logs recording energy and climate data? Is occupancy-based lighting control active? These are binary questions with checkable answers.
Ongoing performance proof. Class A buildings generate continuous, structured data on energy consumption, indoor climate quality, and system behavior. That data is the backbone of ESG reporting, green building certification, regulatory compliance, and investor disclosure — not a manual estimate, but an automated, traceable record.
Who this guide is for
The guide is written for everyone involved in making decisions about building technical systems: building owners and investors assessing upgrade options, facility managers navigating compliance requirements, planners and engineers specifying automation systems, and sustainability and ESG teams looking for reliable performance data to underpin their reporting.
Whether you are planning a new build, evaluating a retrofit, or trying to understand how your existing portfolio maps against current regulatory expectations, the guide walks through the relevant EU policy landscape, the ESG case for advanced automation, and the practical mechanics of the standard itself.