Energy audit: the first step towards energy efficiency.

In recent years, energy management has gone from being a simple cost item to becoming a strategic lever for the economic, environmental, and financial sustainability of companies, condominiums, commercial buildings, and public administrations.

Volatile energy prices, evolving regulatory frameworks, and decarbonization objectives make it increasingly important to know how much energy is consumed, where it is consumed, and, above all, why it is consumed.

An energy audit represents the starting point for building an efficiency strategy based on measurable data, technical priorities, and economic assessments.

It is therefore not simply a document that captures consumption: it is a guide for deciding where to intervene, with which technologies, and with what return on investment.

What is an energy audit and what is its purpose?

An energy audit is a systematic procedure aimed at understanding the energy consumption profile of a building, a group of buildings, an activity, or a process.

The objective is to:

• reconstruct and analyze energy consumption;
• identify the main energy uses;
• identify inefficiencies in the building envelope and systems;
• verify management and regulation methods;
• quantify potential savings;
• identify and compare possible efficiency measures;
• evaluate costs, benefits, and payback periods;
• define intervention priorities.

The diagnosis then transforms energy data into useful information for planning and investment decisions.

Energy diagnosis and APE: what’s the difference?

Energy diagnosis and APE (Energy Performance Certificate) are different tools, with different purposes.

APE – Energy Performance Certificate

The APE is a document required by national regulations on the energy performance of buildings. It expresses the energy performance of a building or real estate unit through specific indicators and assigns an energy class from A4 to G.

It is used, among other things, in sales, leases, new constructions, and interventions where required by law.

The primary reference is Legislative Decree 192/2005, subsequently amended and supplemented, among other things, by Law 90/2013 and Legislative Decree 48/2020, as well as by the implementing decrees of June 26, 2015.

The regulations are national, but the issuance, transmission, inspections, and lists of certifiers are managed within the regional systems and autonomous provinces. The regions contribute to the national SIAPE system managed by ENEA. Therefore, operating procedures may differ from region to region and must be verified based on the region in which the property is located.

The APE therefore describes the energy performance according to a standardized methodology and does not replace an energy audit.

Energy audit

An energy audit, on the other hand, is an in-depth and customized engineering analysis.

When available, it begins with actual consumption and usage profiles of the building or process and integrates:

document analysis;
on-site inspections;
Geometric and system surveys;
Measurements;
Energy data analysis;
Energy modeling and balances;
Identification of inefficiencies;
Technical and economic evaluation of interventions.

The result is not simply an energy class, but a roadmap of interventions, with an estimate of savings, required investments, and payback periods.

In summary: the APE indicates a building’s energy performance; the energy audit explains how it functions, where it consumes energy, and how it can be improved.

Main regulatory references

The energy audit can be developed according to the regulatory and technical framework applicable to the specific case.

UNI CEI EN 16247

The UNI CEI EN 16247 series is the main technical reference for energy audits. The currently valid version includes:

• UNI CEI EN 16247-1:2022 – general requirements;
• UNI CEI EN 16247-2:2022 – energy audits of buildings;
• UNI CEI EN 16247-3:2022 – Energy audits of processes;
• UNI CEI EN 16247-4:2022 – Energy audits of transport;
• UNI CEI EN 16247-5:2015 – Energy auditor skills.

For buildings, UNI/TR 11775:2020 is also available, which provides operational guidelines for the application of UNI CEI EN 16247-2, from data collection to energy inventory creation, cost-benefit analysis, and prioritization of interventions.

Legislative Decree 102/2014

Legislative Decree 102/2014, as amended, constitutes the primary legislative framework for the energy audit requirement for large and energy-intensive businesses.

Article 8 specifically requires mandatory audits to be conducted every four years for obligated entities and regulates the requirements for those responsible and the transmission of results to ENEA.

Among the most significant changes is Legislative Decree 73/2020, which updated several aspects of the regulation.

UNI CEI 11339:2023

UNI CEI 11339:2023 defines the professional requirements of the Energy Management Expert (EGE).

UNI CEI 11352

UNI CEI 11352 defines the requirements for ESCos – Energy Service Companies, including the organizational, diagnostic, design, management, and economic-financial capabilities required to provide energy efficiency services.

Law 10/1991

Law 10/1991 represents one of the main historical Italian references regarding the rational use of energy and the reduction of energy consumption.

The relevant provisions have been profoundly integrated and modified over time by subsequent legislation on the energy performance of buildings, particularly Legislative Decree 192/2005 and subsequent implementing measures.

When is it mandatory and when is it voluntary?

Mandatory Energy Audit

Article 8 of Legislative Decree 102/2014 requires energy audits for:

• large businesses, according to the size criteria established by the legislation;
• energy-intensive businesses falling within the relevant regulatory scope.

The audit must be performed every four years.

For large companies that have adopted an ISO 50001-compliant energy management system, the requirement for periodic audits can be fulfilled through the management system, provided that it includes an energy audit that complies with the regulatory requirements.

For energy-intensive companies, the regulation also provides specific obligations regarding efficiency measures identified by the audit or, alternatively, the adoption of an ISO 50001-compliant energy management system.

And ISO 50001?

ISO 50001 is not simply a documentary alternative to the audit: it is an energy management system aimed at continuously improving the organization’s energy performance.

For a company with significant energy consumption, the combination of:

Energy audit + action plan + ISO 50001 + continuous monitoring

can enable the transition from periodic analysis to a truly permanent energy management system.

It is also important to distinguish the 50 toe threshold, established by Italian legislation for the exemption of large businesses with overall consumption below this value, from the new thresholds established by EU Directive 2023/1791, which introduces a different criterion based on the company’s average energy consumption. The European directive, once fully implemented, requires audits for average consumption exceeding 10 TJ and the adoption of an energy management system for consumption exceeding 85 TJ; the Italian implementation framework must be reviewed in light of the relevant national implementation.

Voluntary Energy Audit

For SMEs, condominiums, commercial properties, hospitality facilities, residential care homes, public buildings, and other real estate assets, an audit can be a voluntary planning tool.

In these cases, it allows you to:

• understand actual consumption;
• identify the main critical issues;
• avoid non-priority investments;
• compare different technological solutions;
• estimate the economic return on interventions;
• plan investments over time;
• supporting requests for funding or access to specific incentives, when applicable;
• integrating energy interventions with overall building and system redevelopment.

Who can perform an energy audit?

For mandatory energy audits pursuant to Article 8 of Legislative Decree 102/2014, the law requires the use of qualified professionals according to the applicable standards, specifically:

• EGE – Energy Management Expert: a professional certified by an accredited body according to UNI CEI 11339;
• ESCo – Energy Service Company: a company certified according to UNI CEI 11352, with the necessary expertise to offer integrated energy services.

For voluntary audits, the choice of professional must be consistent with the complexity, sector, size, and objectives of the assignment.

In short, an energy audit is not simply a formal requirement, but rather the compass that guides every efficiency decision. Whether performed by regulatory obligation or as a voluntary strategic choice, it transforms consumption data into a concrete action plan, allowing investments to be planned with certain payback periods and starting a path towards economic and environmental sustainability.