National foreword

This British Standard is the UK implementation of ISO 50002‑2:2025.

The UK participation in its preparation was entrusted to Technical Committee SEM/1, Energy Management.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2025.

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 301, Energy management and energy savings.

A list of all parts in the ISO 50002 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user's national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

An energy audit can help an organization identify opportunities to improve energy efficiency. It can be part of a site-wide energy management system (EnMS). Energy audits in buildings can help to achieve improvements such as:

energy conservation;
energy efficiency;
improved occupant comfort, health and well-being;
sustainability goals and targets;
climate resilience.

The benefits to the organization can include:

reduced energy and operating costs;
improved information for asset management;
wiser investment strategy based on energy audit results;
meeting organizational goals related to greenhouse gas (GHG), emissions reduction net zero, materials use, productivity and occupant satisfaction.

The use and operation of buildings requires the provision of services such as heating, cooling, ventilation, lighting, domestic hot water, transportation systems (e.g. elevators, escalators, moving walkways) in buildings, information systems and processes. In addition, the operation of buildings typically involves other energy end uses such as appliances or plug loads within the building.

A building's energy consumption depends on:

local climate conditions;
the characteristics of the building envelope;
the age and typology of the building(s)
the designed indoor environment conditions;
the characteristics and settings of the technical building systems;
activities and processes in the building;
occupant behaviour and operational regime.

When dealing with buildings, the audited objects are sometimes similar, technically simple and numerous (e.g. in the residential sector), but can also be unique, complex and highly technical (such as hospitals, swimming pools and spas, etc.).

Energy audits in buildings may include the whole building, parts of the building or some particular technical system.

Energy performance indicators (benchmark values, if available) or average statistical specific energy consumption data are usually published nationally for different building types and ages. This information can be used in the analysis to provide comparative energy performance evaluation. Where this information is not available, comparable data can be found for similar climates through international sources (e.g. the International Energy Agency (IEA)).

NOTE The energy audits covered by this document can be independent from building energy performance certification.

Energy audits and energy saving opportunities identified in energy audits are best implemented in the context of an EnMS, such as one consistent with ISO 50001. Whether or not an organization has an EnMS in place, organizations are more likely to achieve the intended outcomes of an energy audit when their top management supports the audit objective(s) and agrees to provide sufficient resources for the audit process and post-audit activities.

1 Scope

This document gives guidance on how to apply ISO 50002‑1 to carry out energy audits of a building or group of buildings (new or existing). It is intended to be used in conjunction with, and is supplementary to, ISO 50002‑1.

This document does not apply to other areas such as process audits (see ISO 50002‑3), specific energy systems (e.g. compressed air) or transport.

This document is applicable to buildings and can be used independently or in conjunction with ISO 50002‑3.

2 Normative references

3 Terms and definitions

4 Principles of energy auditing

5 Performing an energy audit

5.1 General

5.2 Planning

5.3 Opening meeting

5.4 Data collection

5.5 Measurement plan

5.6 Site visit

5.7 Analysis

5.8 Reporting

5.9 Closing meeting

6 Competence of the energy auditor

Bibliography

BS ISO 50002-2:2025

Energy audits - Guidance for conducting an energy audit using ISO 50002-1 in buildings

Current

Published:

30 Jun 2025