Mis à jour le 13 juin 2026

The energy audit of a commercial building has become a mandatory step for many businesses. It is not just a regulatory obligation, but above all a practical tool to better understand where your energy is going and how you can consume less. We will look together at what this entails, how it works, and why it is a good thing for your business and for the planet.

Key Points of a Commercial Building Energy Audit

• A commercial energy audit allows for an assessment of a building’s energy consumption, identification of waste sources, and proposal of concrete solutions to reduce expenses.
• Conducting an audit follows a precise methodology, including document analysis, a site visit, and modelling to assess energy performance.
• The audit results translate into costed work scenarios, with an estimate of potential savings and return on investment.
• The regulatory framework, particularly the tertiary decree and future developments, makes this audit increasingly important for building compliance.
• Having a commercial energy audit carried out by a qualified professional brings economic and environmental benefits and allows for adaptation to future legal requirements.

Understanding the Energy Audit of a Commercial Building

An energy audit of a commercial building is a bit like a complete health check-up for your property. It is a structured process that aims to examine in detail how your building consumes energy. The main objective is to identify waste and pinpoint concrete areas for improvement to reduce your consumption. This is a key step, especially with evolving regulations and the need to make our buildings more efficient.

Definition and Objectives of a Commercial Energy Audit

In practical terms, a commercial energy audit is a thorough assessment of a building’s energy performance. It goes beyond just looking at bills; it analyses the building envelope (insulation, windows), heating, ventilation, and air conditioning (HVAC) systems, lighting, and even specific uses related to your business activity. The idea is to create an accurate picture of current consumption in order to propose suitable solutions. The objective is twofold: to reduce energy costs and to decrease environmental impact.

Distinction Between Technical Assessment and Action Plan

It is important to understand that the audit is divided into two main parts. Firstly, there is the technical assessment: this is where current performance is measured, thermal losses are identified, and the condition of equipment is evaluated. Secondly, based on this diagnosis, an action plan is developed. This plan proposes work scenarios, ranked by priority, with an estimate of costs, potential savings, and payback period. It is this combination that makes the audit truly useful for making informed decisions.

Importance of the Energy Audit in the Current Context

In the current context, where climate challenges and rising energy costs are at the forefront, the energy audit takes on its full significance. It not only ensures compliance with regulatory obligations, such as the tertiary decree, but also leads to substantial savings. It is a tool that helps businesses manage their resources better, improve occupant comfort, and engage in sustainable development. The audit provides a clear roadmap for optimising the energy performance of your commercial building.

Methodology for Conducting a Commercial Energy Audit

The process of conducting an energy audit for a commercial building follows a structured approach, primarily guided by the NF EN 16247 standard. This methodology aims to obtain an accurate picture of energy consumption and identify the most relevant areas for improvement.

Document Analysis and Energy Data Collection

The first step involves gathering and examining all relevant documents. This includes energy bills over several years to understand consumption trends, building plans, technical system schematics (heating, ventilation, air conditioning, lighting), as well as existing operational data. The objective is to identify dominant energy uses and pinpoint seasonal or annual variations. This preliminary phase helps define the exact scope of the audit and prepare for the site visit. It is important to clearly define the reference year for future comparisons, especially within the framework of the tertiary decree.

In-depth Technical Site and Systems Visit

Once the documentation has been analysed, the auditor visits the site for a detailed inspection. They assess the actual condition of the building envelope (insulation of walls, roofs, floors, windows) and the operation of the technical systems. This includes heating, domestic hot water production, ventilation, air conditioning, lighting, as well as building management systems (BMS) and control systems. The auditor observes equipment in operation, checks its performance, and compares it with the collected data. Interviews with technical staff and occupants may also take place to better understand usage practices and any potential malfunctions.

Thermal Modelling and Detailed Energy Balance

Based on the data collected and observations made on site, the auditor performs thermal modelling of the building. This work allows for the simulation of energy flows and precise quantification of consumption by use (heating, air conditioning, lighting, etc.). The energy balance highlights the major sources of consumption and the main areas of thermal loss. This comparative analysis with reference buildings helps identify the most significant energy saving potentials. The results are then presented in a clear report, detailing current performance and proposing concrete improvement measures.

Rigor in data collection and precision in modelling are the guarantees of the reliability of the recommendations made in the energy audit.

Content and Deliverables of a Commercial Energy Audit

A commercial building energy audit is a structured process aimed at providing a clear picture of current energy performance and proposing concrete improvement measures. It is not just a diagnosis, but a genuine decision-making tool for planning renovation work.

Identification of Consumption Sources and Losses

The first step is to draw up a precise inventory of how energy is consumed in the building. This includes analysing heating, ventilation, and air conditioning (HVAC) systems, lighting, domestic hot water production, as well as electrical equipment specific to the building’s uses. At the same time, the audit identifies weak points in the building envelope that lead to heat loss. This includes insulation of attics, walls, floors, as well as thermal bridges and air leaks. The objective is to quantify these losses to better target interventions. The NF EN 16247 standard details the requirements for this analysis, particularly regarding the measurement of consumption for significant uses [6fcf].

Graduated and Prioritised Work Scenarios

Following the analysis, the auditor proposes several work scenarios. These scenarios are generally presented in a graduated manner, ranging from the simplest and quickest actions to implement (such as optimising system settings) to more significant and structural renovations (external insulation, window replacement, HVAC system upgrades). Each scenario is designed to meet regulatory obligations, such as those of the Tertiary Decree, and is evaluated according to its potential effectiveness, technical feasibility, and cost.

Estimation of Costs, Potential Savings, and Return on Investment

For each proposed work scenario, the audit provides essential quantified information for decision-making. This includes a projected estimate of investment costs, the potential for energy savings achievable (expressed in kWh Cumac), and an analysis of the return on investment (ROI). The audit also details available financial aid, whether it be Energy Saving Certificates (CEE), ADEME schemes, or local authority support. An element often included is the analysis of the cost of inaction, which puts into perspective future expenses related to equipment ageing or performance decline if no action is taken.

All these elements constitute a complete dossier enabling building managers to plan a relevant and economically viable energy renovation strategy, while complying with current regulatory frameworks.

Regulatory Obligations and Future Developments

The regulatory framework surrounding energy audits in the commercial sector is undergoing significant changes, particularly with developments planned for 2026. These changes aim to enhance energy efficiency and align French practices with European directives. It is therefore essential for businesses to stay informed to anticipate these new requirements.

Compliance with the Tertiary Decree and European Standards

The tertiary decree, which came into effect to impose energy consumption reduction targets on commercial buildings, is a cornerstone of current regulation. It mandates progressive reductions by 2050. The energy audit is a key tool for assessing a building’s current performance and defining a relevant action plan to achieve these objectives. The European standard NF EN 16247 also governs the methodology for conducting these audits, ensuring a structured and comparable approach.

Regulatory Developments Planned for 2026

From October 2026, a major development will redefine the scope of the audit obligation. From now on, it will not solely be the building type that determines the obligation, but primarily the company’s actual energy consumption. Companies whose final energy consumption exceeds a certain threshold, set at 2.75 GWh per year on average over the last three years, will be concerned. This change, stemming from the transposition of a European directive, potentially broadens the number of entities subject to this obligation. The audit must cover at least 80% of the company’s final energy consumption, potentially including buildings, industrial processes, internal transport, and other significant uses.

Possible Exemptions for ISO 50001 Certified Companies

For very large energy consumers, whose consumption exceeds 23.6 GWh/year, an additional obligation is planned for 2027: the implementation of an energy management system (EMS). Companies that successfully obtain ISO 50001 certification for their EMS, covering the entire concerned scope, may be exempt from the obligation to carry out a statutory energy audit. This certification attests to a structured and continuous approach to improving energy performance. It is important to note that the energy audit remains a useful prerequisite for identifying areas for improvement that can then be integrated into the EMS framework.

Regulation is evolving to better target the largest energy consumers. The energy audit is becoming a broader tool, adapting to actual consumption rather than just building classification.

Accredited Professionals for Conducting Energy Audits

For a commercial energy audit to be recognised and useful, it must be carried out by qualified experts. This is not a task to be taken lightly, as the reliability of the results directly depends on the skills of the person conducting the audit. It is essential to ensure that the chosen professional possesses the necessary technical and regulatory knowledge.

Qualifications and Certifications Required for Auditors

The first thing to check is the auditor’s certification. To be compliant, particularly with the NF EN 16247 standard, the professional must be certified by an accredited body. In France, organisations such as OPQIBI, LNE, or AFNOR Certification issue these certifications. These labels attest that the auditor has the skills to analyse the energy consumption of a commercial building in detail and propose concrete solutions. It is imperative that the auditor is independent to ensure the objectivity of their report.

Types of Authorised Professionals: Engineering Firms, Engineers, Consultants

Several types of organisations and professionals are authorised to conduct these audits. Specialised engineering firms in energy and construction are often involved. These teams include energy engineers who have in-depth knowledge of heating, ventilation, air conditioning, and lighting systems. Independent energy efficiency consultants can also be engaged. Sometimes, architects who have undergone specific training can also conduct these audits, especially if they have a dual expertise in buildings and technical systems. The important thing is that they master both building thermal performance and technical equipment. It is advisable to look at their references on projects similar to yours.

Criteria for Choosing a Qualified Service Provider

Choosing the right service provider is a key step. Beyond certification, it is essential to ensure the professional’s independence. They should have no commercial ties with companies that might carry out the recommended work, to avoid any conflict of interest. Good communication is also important; the auditor must be able to clearly explain their methodology and conclusions. Do not hesitate to request multiple quotes and compare the proposed approaches. A preliminary site visit by the service provider can also be a good indicator of their seriousness and understanding of your challenges. The goal is to obtain a reliable energy audit that will serve as a solid basis for your action plan.

Economic and Environmental Benefits of the Audit

Significant Reduction in Energy Bills

One of the most direct benefits of an energy audit is a noticeable reduction in energy expenditure. By precisely identifying where energy is consumed and where losses occur, the audit allows for targeting the most effective actions. This goes beyond simply changing light bulbs; it involves a in-depth analysis of heating, air conditioning, lighting systems, and building insulation. Better management of these areas can lead to substantial savings, sometimes in the region of 20 to 30% on annual bills. This translates into a direct improvement in the company’s profitability.

Contribution to the Energy Transition and GHG Reduction

Beyond financial aspects, the energy audit plays a key role in a company’s commitment to ecological transition. By reducing its energy consumption, an organisation mechanically decreases its greenhouse gas (GHG) emissions. This is a concrete step towards contributing to the fight against climate change and improving its brand image with customers, partners, and employees. The audit provides a clear roadmap for achieving environmental performance objectives.

Improvement of Overall Building Performance

An energy audit is not limited to energy. It offers a holistic view of the building’s condition. Recommendations can concern improving occupant comfort, enhancing property value, or preparing the building for future thermal regulations. Here are some examples of potential improvements:

• Optimisation of ventilation systems for better indoor air quality.
• Upgrading insulation for increased thermal comfort in all seasons.
• Modernisation of equipment for increased reliability and efficiency.
• Integration of building management system (BMS) solutions for finer consumption control.

The energy audit is a strategic investment that not only leads to immediate financial savings but also positions the company as a responsible environmental player, while improving the quality of its premises.

Financing of Energy Audits in the Commercial Sector

ADEME Support Schemes

The French Agency for Ecological Transition (ADEME) plays an important role in providing financial support for energy audits in commercial buildings. It offers grants that can cover a significant portion of the costs. The rate of coverage varies depending on the size of the company: small businesses can benefit from aid of up to 70%, medium-sized businesses up to 60%, and large companies up to 50%. It is important to note that these aids are capped, generally at €50,000 for the diagnostics themselves. These schemes aim to encourage commercial sector players to carry out these assessments, even when the audit is not strictly mandatory.

Financial Support from Local Authorities

In addition to national aid, many local authorities, whether regions, departments, or municipalities, have implemented their own support programmes. These local schemes can complement ADEME aid and offer even more advantageous conditions. It is therefore advisable to inquire with local bodies to find out about specific funding opportunities in your area. For example, some programmes specifically target educational institutions, significantly increasing the subsidy rate for energy audits.

Mobilisation of Energy Saving Certificates (CEE)

Energy Saving Certificates (CEE) represent another significant source of funding for energy audits in the commercial sector. This scheme, supported by energy suppliers, allows for the valorisation of energy efficiency actions. A well-conducted energy audit, leading to renovation work, can qualify for CEE. It is possible to use these certificates to finance all or part of the audit itself, or to reduce the cost of the recommended work. Good financial engineering can maximise available CEE premiums, thus making the audit project more accessible. ISO 50001 certified companies can also benefit from specific support within the framework of these schemes, particularly for sites with high energy consumption.

Specific Cases and Scope of the Audit

The energy audit of a commercial building is not a single, standardised process. Its application and scope vary considerably depending on the nature of the building, its uses, and the objectives set. It is therefore essential to clearly define the scope of the analysis from the outset to ensure the audit’s relevance and effectiveness.

Adapting the Audit to Different Types of Commercial Buildings

Each type of commercial building presents specific challenges. An office, a shopping centre, a hospital, or a logistics warehouse do not have the same needs or the same energy consumption sources. For example, in a shopping centre, HVAC and lighting often represent a predominant share of expenses. For a warehouse, lighting needs can be significant, but HVAC systems less complex. The audit must therefore be adapted to target the most significant areas for each type.

Precise Definition of the Analysis Scope

Defining the scope is a key step. It involves clearly delineating the areas, installations, and equipment that will be studied. This may include one or more buildings, specific areas within a building, or even central technical equipment serving multiple entities. It is important that this scope is consistent with the audit objectives and regulatory obligations, such as those imposed by the tertiary decree. The objective is to cover at least 80% of the audited entity’s final energy consumption.

Taking into Account Specific Uses and Occupant Behaviour

Beyond technical aspects, the audit must consider the actual uses of energy and occupant behaviour. For example, in an office building, occupancy hours, the use of IT equipment, or even temperature settings by employees directly influence consumption. Similarly, in a healthcare facility, ventilation and domestic hot water production needs are often more significant and continuous. In-depth analysis of practices and habits can identify often-overlooked saving opportunities, which are not solely related to technical improvements of installations but also to the optimisation of *uses*.

Here are the main elements to consider when defining the scope and uses:

• Buildings concerned: Exhaustive list of buildings included in the audit.
• Technical installations: Heating, ventilation, air conditioning, hot water production, lighting systems, etc.
• Specific equipment: IT equipment, industrial machinery, medical equipment, etc.
• Energy uses: Heating, air conditioning, lighting, ventilation, processes, domestic hot water, etc.
• Behaviours: Occupancy hours, thermostat settings, equipment use by occupants.

The expansion of the audit scope, particularly since regulatory changes, can include not only buildings but also industrial processes, internal transport, and any other significant energy use. This comprehensive approach allows for better identification of saving potentials. The energy audit is a process aimed at identifying energy flows and areas for improvement, in line with new regulations in force.

It is also important to note that the audit methodology must remain governed by the NF EN 16247 standard, which provides a framework for conducting these studies.

In this section, we examine specific cases and the scope of our audit. We want to ensure everything is clear for you. If you have any questions or would like to know more about how we can help you, please do not hesitate to visit our website for more information.

An Indispensable Tool for Your Building’s Energy Future

In summary, a commercial building energy audit is not just an administrative formality. It is a truly useful process for understanding where your energy is going, finding ways to consume less, and ultimately, reducing your bills. With new rules on the horizon, particularly in 2026, taking action now is a good idea. It allows you to calmly plan the necessary work, seek available financial aid, and ensure your building is ready for future requirements. It is a sensible investment, both for your wallet and for the planet.

Frequently Asked Questions

What is an energy audit for a building like an office or a shop?

It’s like a health check-up for a building’s energy. We look at where energy is used, where there’s waste, and we propose solutions to spend less and be more environmentally friendly. It’s more in-depth than a simple check.

Why do this audit, is it mandatory?

Yes, it’s often mandatory, especially for large commercial buildings, due to laws like the ‘tertiary decree’. The idea is to reduce our energy consumption to help the planet and also to save money on bills.

Who can do this audit?

It’s not just anyone. It must be a qualified and certified professional, such as a specialised engineering firm or an energy engineer. They have the knowledge to properly analyse the building.

What do you get after the audit?

You receive a detailed report. It explains where the energy is going, what the problems are, and most importantly, it proposes work to be done, ranked by importance and cost. You know how much it will cost, how much you will save, and how long it will take for the investment to pay for itself.

Is it expensive to do this audit?

The price varies depending on the size of the building and its complexity. But there are financial aids available, such as those from ADEME or local grants, which can cover a significant portion of this audit, especially for small and medium-sized enterprises.

What is the ‘tertiary decree’?

It’s a law that requires large buildings (over 1000 m²) to reduce their energy consumption over several years. The audit helps to figure out how to achieve these goals.

If a company has ISO 50001 certification, is it obliged to do the audit?

No, having this certification already proves that the company manages its energy well. Therefore, it is often exempt from carrying out the mandatory energy audit.

What are the concrete benefits of an energy audit?

The benefits are twofold: energy bills are reduced, which is good for the company’s finances, and it contributes to environmental protection by reducing pollution and greenhouse gas emissions.