- 1An audit covers all energy; Bilan Carbone® covers all emissions: neither of the 2 replaces the other.
- 2In services, energy often accounts for only 10 to 15% of emissions; scope 3 accounts for most of the footprint.
- 3An audit costs €3,000 to €10,000 excl. VAT, a Bilan Carbone® €10,000 to €30,000 excl. VAT, or €6,000 excl. VAT with Diag Décarbon'Action.
- 4For a manufacturer, footprint first, audit next, unless a mandatory audit deadline applies, with funding that can be combined.
- Energy audit or Bilan Carbone®: which should you choose?
The 2 are complementary: neither replaces the other.
- Energy audit: €3,000 - €10,000 excl. VAT, to optimise energy consumption (gas, electricity, fuels).
- Bilan Carbone®: €10,000 - €30,000 excl. VAT depending on complexity (€6,000 excl. VAT with Diag Décarbon'Action), to measure all emissions.
- In the service sector, energy often accounts for only 10 to 15% of emissions. For an industrial company without a mandatory audit deadline: footprint first, audit afterwards.
Many managers see an energy audit as a simplified Bilan Carbone®, because it concerns energy and costs less. The 2 tools answer different questions.
1Different objectives and scopes
An energy audit is a technical assessment that identifies the energy consumption sources of a building, industrial site or fleet and proposes optimisation options. It examines gas, electricity and fuel consumption, insulation, equipment and uses. It produces a list of works or actions ranked by profitability (return on investment, payback period), according to the reference standard NF EN 16247.
Energy audit ≠ Bilan Carbone®
Click an area of the diagram to see what each tool actually measures.
A Bilan Carbone® measures an organisation's greenhouse gas emissions: scope 1 (direct emissions), scope 2 (purchased energy) and scope 3 (everything else: purchases, upstream freight, travel, sold products, end of life). It produces an inventory in tCO2e by source, a climate action plan and a decarbonisation pathway, with emission factors drawn from ADEME's Base Empreinte.
An energy audit therefore covers all energy, but only the share of emissions arising from it: often 10 to 15% in a service company, much more in an energy-intensive industry. Bilan Carbone® covers all emissions and treats energy as one source among others, with less technical detail.
2What costs what in 2026
A statutory energy audit, mandatory every 4 years for companies consuming at least 2.75 GWh of energy per year, costs €4,000 to €10,000 excl. VAT depending on site size. It follows NF EN 16247 and must be carried out by a qualified auditor (OPQIBI, AFNOR Certification).
A voluntary energy audit for an SME costs €3,000 to €7,000 excl. VAT, often with 30 to 50% funding from ADEME, through Bpifrance's Diag Eco-Flux, or from regional funding.
A complete Bilan Carbone® (scopes 1, 2 and 3) for an SME costs €10,000 to €30,000 excl. VAT as a privately commissioned service, depending on complexity, with a remaining cost of €6,000 excl. VAT through Diag Décarbon'Action.
A statutory greenhouse gas emissions report (BEGES), mandatory every 4 years for companies with more than 500 employees (250 in overseas territories), costs €12,000 to €25,000 excl. VAT depending on complexity. The comparison is detailed in our explanation of BEGES or Bilan Carbone®.
An energy audit almost always costs less, because its scope is narrower: it does not require scope 3 data collection (purchases, upstream freight, capital goods, etc.), which represents 60 to 80% of the workload of a complete Bilan Carbone®.
3What each tool does not replace
A common mistake is to believe that an audit can replace a footprint assessment, or vice versa. The 2 complement each other, and each leaves out needs that the other covers.
An energy audit does not replace:
- BEGES, a separate requirement under the Environmental Code (the audit, for its part, derives from the European Energy Efficiency Directive): a company with more than 500 employees consuming at least 2.75 GWh per year must carry out the 2 assessments;
- CSRD requirements (ESRS E1 standard), which concern material scopes 1, 2 and 3 and a decarbonisation pathway, of which an audit covers only a fraction;
- the response to a major customer wanting your footprint for its own scope 3: it expects a Bilan Carbone®;
- B Corp certification: the April 2025 B Lab standards require a quantified climate action plan from all companies and a verified GHG inventory from large ones;
- an SBTi commitment, which requires a pathway covering all emissions, rather than energy alone.
Conversely, a Bilan Carbone® does not replace an energy audit. It identifies emission sources at an aggregated level ("site heating = X tCO2e") without examining the technical details of a boiler, control system or heat recovery system. At an industrial client, the footprint assessment showed that 40% of scope 1 emissions came from the firing kiln, but nobody in the team knew what to do with that figure. The energy audit carried out 6 months later quantified 3 replacement scenarios, with their return on investment according to the gas price, and the investment decision was made on this basis.
For a company with a significant energy issue (industrial site, large commercial building, substantial fleet), the footprint assessment identifies the sources to address and the audit provides the technical action plan.
4When to do one, the other or both
Start with an energy audit if your company consumes a lot of energy (industry, logistics, retail with a large building portfolio), if you are subject to the mandatory audit (at least 2.75 GWh consumed per year, with a first audit due no later than 11 October 2026 for newly affected companies), if you seek a quick return on investment from efficiency works, or if you are eligible for Diag Eco-Flux or ADEME funding dedicated to energy.
Start with Bilan Carbone® if your company is in services or has substantial purchasing activity (emissions are not dominated by direct energy), if you are subject to BEGES or the CSRD, if you are preparing for B Corp certification, an EcoVadis assessment or an SBTi commitment, or if a major customer asks for your carbon footprint.
Carry out the 2 assessments, starting with the footprint assessment, if you are an industrial company or a company with substantial property holdings with 50 to 500 employees and no mandatory audit deadline: Bilan Carbone® shows where the emissions are, then the energy audit examines the scope 1 and 2 sources considered priorities in detail. If the mandatory audit falls due first, do it first and use its consumption readings for the footprint assessment.
5In what order to carry them out
An energy audit never serves as a Bilan Carbone® for authorities, investors or customers. A director with an up-to-date audit but no footprint assessment remains non-compliant with BEGES if subject to it, lacks the information needed for the climate dimension of CSR labels, and cannot respond to a major customer's carbon request. Nor does a Bilan Carbone® exempt the company from the mandatory energy audit, which applies every 4 years to companies consuming at least 2.75 GWh of energy per year; above 23.6 GWh, an ISO 50001-certified energy management system becomes mandatory. Outside a regulatory deadline, an industrial or property company benefits from conducting the footprint assessment first and the audit next: the footprint assessment identifies the sources that matter, while the audit quantifies investments.
Which tool for which company profile
The right sequence depends on the activity's actual energy intensity.
Comparing their prices therefore makes little sense: the useful question concerns the sequence suited to your activity profile, and in most cases you will need the 2 tools, using funding that can be combined.
