Tertiary decree 2026: air conditioning at the heart of HVAC obligations for buildings over 1,000 m²

1 July 2026 is a date to mark in red for owners and operators of tertiary buildings over 1,000 m²: from that day on, the Éco Énergie Tertiaire (EET) digital attestation must be displayed in the building. Three months later, on 30 September 2026, 2025 consumptions must be declared on ADEME's OPERAT platform. For businesses that have not yet aligned their HVAC and their air conditioning with these obligations, the time has come to take action — under threat of formal notices and fines of up to €7,500 per building. Here is the Proclimo guide to understanding, prioritising and successfully achieving compliance in 2026.

What the tertiary decree (really) says

Decree no. 2019-771 of 23 July 2019, known as the "tertiary decree" or "Éco Énergie Tertiaire", transposes Article 175 of the ÉLAN law. It requires all buildings used for tertiary activities whose cumulative floor area is ≥ 1,000 m² on the same land parcel (several adjoining buildings can be added together) to progressively reduce their final energy consumption:

• −40 % by 2030,
• −50 % by 2040,
• −60 % by 2050,

compared with a reference year freely chosen between 2010 and 2019. Under the decree of 6 September 2025, two calculation methods are possible: the relative method (percentage reduction) or the absolute method (kWh/m²/year threshold defined by activity).

The decree of 1 August 2025 (which came into force on 7 September 2025) ended the transitional period and extended CABS thresholds to new sectors. The digital attestation became mandatory from 1 July 2026, and must also be annexed to new commercial leases and to sale deeds.

Who is concerned (and who is not)

The decree targets buildings whose main use is tertiary: offices, head offices, shops, large stores, shopping centres, health and education establishments, hotels and restaurants, logistics warehouses, State and local authority buildings. Owners and tenants are jointly liable.

Excluded: places of worship, temporary buildings (< 2 years), defence and civil security sites, and buildings whose cumulative floor area is strictly below 1,000 m².

📊 OPERAT 2024 data: out of 920,000 theoretically covered premises, only 291,000 "functional and covered entities" (EFA) had been declared by 31 January 2024. Around 43 % of businesses were already behind on the 2030 trajectory — and the 2026 heatwave has not helped matters.

Air conditioning and HVAC: the first item concerned

In a tertiary building, HVAC (Heating, Ventilation, Air Conditioning) accounts for 40 to 60 % of final energy consumption, far ahead of lighting and specific uses. It is therefore on this item that the most powerful technical levers sit.

Three levers combine to reach your 2030 targets:

1. The intrinsic performance of the equipment: replace old split, rooftop or VRF units with high-efficiency reversible heat pumps, eligible for reduced VAT at 5.5 % and CEE bonuses.
2. Automation and control: a BMS / BACS becomes essential to monitor, regulate and optimise air conditioning, heating and ventilation in real time — a 10 to 25 % gain documented by ADEME.
3. The envelope and ventilation: external insulation, thermal bridge treatment, night free cooling. An approach that fits with the logic detailed in our article on cooling a home without air conditioning during a heatwave, which can be scaled to an office floor.

The two critical deadlines in 2026

Date	Obligation	Risk in case of delay
1 July 2026	Display the EET digital attestation in the building, and annex it to leases	Non-compliance, formal notice
30 September 2026	Declare 2025 consumptions on OPERAT	Automatic formal notice (3 months to regularise)
11 October 2026	Mandatory energy audit for businesses consuming > 2.75 GWh/year	Administrative fine
30 September 2027	Submission of the Modulation Technical File (DTM) if you request a modulation for the 2030 trajectory	Rejection of the modulation

For buildings rated E, F or G on the DPE, the regulatory energy audit is required in addition. It is also an excellent internal management tool — to be coupled with an adapted maintenance contract that guarantees performance over time.

BMS and BACS decree: an inseparable duo

The BACS decree (Building Automation & Control Systems, no. 2020-887) has required, since 1 January 2025, the installation of a building automation and control system for any HVAC installation with a power above 70 kW. A draft revision for 2026 extends this threshold to collective residential and agricultural buildings, and lowers certain power limits.

In practice, the BMS must enable you to:

• Measure the consumption of each item (heating, air conditioning, ventilation, lighting) in real time.
• Regulate setpoints room by room, according to occupancy, sunshine and electricity tariffs.
• Automatically optimise start-ups, shut-downs, free cooling and domestic hot water production.
• Detect drifts (clogged filters, refrigerant leak, balancing to be redone) before they cause excess consumption.

A class A or B BMS according to the EN 15232 standard delivers 10 to 25 % energy savings on HVAC, with a return on investment of under 5 years — far quicker than a change of equipment.

The Proclimo 7-step action plan

For businesses starting from scratch, here is a proven method:

1. Map your property: areas, uses, HVAC equipment, maintenance contracts, historical consumptions.
2. Choose the reference year and the calculation method (relative or absolute) that best matches your activity.
3. Carry out an energy audit to identify the most profitable items (air conditioning and ventilation are almost always at the top).
4. Define a trajectory: % reduction targeted in 2030, 2040, 2050, and a multi-year works plan.
5. Prioritise HVAC works: reversible heat pump, BMS, insulation, free cooling, terminal regulation.
6. File OPERAT every year (by 30 September at the latest) and display the EET attestation from 1 July 2026.
7. Monitor and adjust: the BMS produces the data, the maintenance contract translates it into concrete actions, and the trajectory is readjusted every year.

Sanctions for non-compliance

Article R. 174-32 of the French Construction and Housing Code provides for a cascade of sanctions:

• Formal notice from the prefecture, with 3 months to regularise.
• Administrative fine: €1,500 per building for a natural person, €7,500 per building for a legal entity — cumulative and renewable every year.
• "Name and shame": publication on an official State website, with a CSR and reputational impact sometimes more costly than the fine itself.
• Ineligibility for certain public contracts and tenders that include ESG criteria.

Conversely, a trajectory genuinely followed enables you to trigger modulation (technical, property-related, economic) via the DTM to be filed before 30 September 2027 for the 2030 milestone.

What financial aid is available for your works?

Several schemes are stackable, subject to respecting the standard sheets:

• CEE 6th period (2026-2030): main financial lever, with bonus for heat pumps. Key sheets: BAT-TH-113 (heat pump), BAT-TH-116 (BMS), BAT-TH-145 (pipe insulation). Note: sheet BAT-EQ-127 (LED relamping) was repealed on 25 February 2026.
• MaPrimeRénov' "major renovation" pathway for buildings rated E, F or G, with aid that can reach 80 % of the pre-tax amount for very modest households (stackable with CEE and éco-PTZ).
• ADEME Heat Fund for renewable and recovered heat projects.
• Regional grants (Île-de-France, PACA, Auvergne-Rhône-Alpes…) often stackable with CEE.
• Éco-PTZ for zero-interest pre-financing of works.

Our article on reduced VAT at 5.5 % on reversible air conditioning details how to use it; the one on the approved PAC Coup de pouce bonus explains the ×5 bonus for "industrial quality and resilience" heat pumps.

Frequently asked questions

My building is 900 m²: am I concerned? No, unless the cumulative area on the same land parcel reaches 1,000 m² (for example a main building of 900 m² + an adjoining annex of 150 m²). The threshold is assessed at the site level, not for the building taken in isolation.

Does a reversible air conditioner count as a "heating" or "air conditioning" item in OPERAT? Both: in the relative method, you declare the total energy consumption, broken down by item (heating, air conditioning, DHW, lighting, specific uses). A reversible heat pump is entered partly under heating and partly under air conditioning, according to the actual share of energy consumed.

What happens if I am behind on the 2030 trajectory? You can file a Modulation Technical File before 30 September 2027 to explain the constraints (technical, property-related, economic) that justify a postponement. Without a DTM, you are in breach and risk a formal notice followed by a fine.

Is the digital attestation really mandatory on 1 July 2026? Yes, this is provided for by the decree of 1 August 2025, with mandatory annexing to new commercial leases and sale deeds from that date.

BMS or maintenance contracts: where to start? In 80 % of cases, the BMS and the maintenance contract are complementary: the BMS measures, the maintenance contract translates this data into actions (filter cleaning, balancing, preventive replacement). Proclimo offers a turnkey BMS + maintenance contract package, eligible for CEE.

Can I be supported for the OPERAT declaration? Yes, and it is recommended: the platform is demanding on the data to be provided (area, energy, calculation method, evidence). A thermal engineering firm or a certified refrigeration contractor such as Proclimo can handle the declaration and the annual follow-up.

Take action with Proclimo

Proclimo supports owners, operators and co-ownership managers in Île-de-France in bringing their tertiary buildings into compliance:

• Regulatory energy audit: a complete review of your HVAC, insulation and BMS, with a quantified 2030-2050 trajectory.
• Installation and replacement of reversible heat pumps: thermal studies, quote within 48 hours, installation by certified refrigeration technicians, ten-year guarantee.
• Tertiary maintenance contract: annual follow-up, refrigerant leak-tightness check, balancing, remote metering, reporting for your DPE and OPERAT.
• BMS / BACS implementation: instrumentation, automation, energy dashboard, BACS decree compliance, eligibility for CEE BAT-TH-116.
• Emergency repair 7 days a week: intervention within 24 to 96 hours in Île-de-France, so a tertiary building is never left without air conditioning in the middle of a heatwave.

Contact Proclimo for a free assessment of your tertiary building and a quantified action plan before 1 July 2026 — or book your intervention online to avoid saturating schedules.