Tertiary energy audit: diagnostics, savings and compliance
2024 regulatory framework: obligations to reduce energy consumption in the commercial building stock, European directive on the energy performance of buildings (EPBD) and requirements relating to building automation and control systems (BACS).
For a Paris office with a 28 EUR/m2/year energy bill, an NF EN 16247-2 audit at 5 EUR/m2 generates 7 to 10 EUR/m2/year in savings from year 2: the 3.5-year ROI is not a sales argument, it is a CFO’s calculation. The French commercial building stock represents around 1 billion m2 (Cerema, Le parc tertiaire en France, 2020, p.12), including 230 million m2 of offices subject to the commercial building decree with its thresholds of -40% in 2030, -50% in 2040 and -60% in 2050 (decree no. 2019-771, articles R174-22 et seq. of the CCH). Kytom carries out the audit in 8 to 12 weeks in accordance with NF EN 16247-2, deploys OPQIBI 1905 certified auditors and has supported more than 1200 commercial clients since 2006. The deliverable prioritises actions according to three criteria: payback period, CO2 emissions avoided and compliance with the commercial building decree and BACS 2023 (decree no. 2023-259).
The commercial building decree (ELAN law, articles R174-22 et seq. of the Construction Code) requires any building over 1000 m2 to submit an annual OPERAT declaration to ADEME. Three texts complement this foundation for French offices.
- Energy Code, article L233-1: mandatory audit every 4 years for companies with more than 250 employees or 50 MEUR in turnover, except for ISO 50001 certification. It must cover 80% of energy bills and comply with NF EN 16247-2 for buildings, in accordance with article 8 of directive 2012/27/EU.
- EPBD directive recast in 2024 (EU directive 2024/1275): strengthened requirements for non-residential buildings, transposed by the DDADUE law.
- BACS decree extended in 2023 (decree no. 2023-259): requirement for a class B BMS in accordance with NF EN ISO 52120-1 on commercial buildings over 290 kW.
Consumption is spread across three main areas according to ADEME (Chiffres clés du bâtiment, 2023 edition, p.34): HVAC (40 to 55%), lighting (15 to 25%), office equipment (10 to 20%). The energy cost of an office ranges between 15 and 35 EUR/m2/year depending on initial performance; this range depends on the building type, its level of equipment and its mode of occupancy.
Our reading differs from the professional consensus on one specific point: the OPERAT penalty capped at 7,500 EUR per year is often presented as negligible, and thus the regulatory risk would be overestimated. This is false for an Asset Manager: the real risk is not the fine, it is the discount on resale of an asset that does not comply with the -40% trajectory in 2030. In our recent portfolio, the valuation gap between comparable D and B assets reaches 7 to 12%, i.e. 280 to 480 EUR/m2 on a Paris office at 4000 EUR/m2. The audit is not a CSR matter, it is an asset value matter.
Frequently asked questions
What is the difference between a regulatory energy audit and a voluntary audit?
The regulatory audit (article L233-1 of the Energy Code) is mandatory every 4 years for companies with more than 250 employees or 50 MEUR in turnover, except for ISO 50001 certification. It must cover 80% of energy bills and comply with NF EN 16247-2. The voluntary audit goes beyond this foundation: scope expanded to 100% of bills, dynamic thermal simulation with 3 to 5 scenarios, action plan prioritised by ROI, OPERAT and CEE support. The voluntary audit delivers savings significantly higher than those of a regulatory audit alone, with measurable effects from the second year.
