BACS decree 2026: Class A GTB mandatory for controlling tertiary air conditioning from 70 kW

Since 1 January 2026, any tertiary building whose combined nominal useful power of heating, air conditioning or DHW production equipment is 70 kW or more must be equipped with a Building Automation and Control System (BACS) compliant with class A of the NF EN ISO 52120-1:2022 standard — i.e., in practice, a smart GTB capable of continuously optimising the energy consumption of air conditioning, heating, ventilation and lighting. The 27 March 2025 order (published in the JORF on 2 April 2025) replaced the initial 290 kW threshold with a 70 kW threshold applicable from this year, and provides for a gradual reduction to 30 kW on 1 January 2028 and then 10 kW on 1 January 2030. For owners, property managers, condominium trustees and operators of offices, retail, hotels, healthcare facilities, nurseries, schools and logistics buildings that have not yet brought their installation into line, summer 2026 is the right time to take action: CEE BAT-TH-116 aid, MaPrimeRénov' Tertiaire and ADEME heat fund remain available, and a class A BACS typically generates 25 to 35% savings on the HVAC bill. Here is the Proclimo guide to understanding, sizing and successfully bringing your tertiary air conditioning GTB into compliance.

The BACS decree, what exactly is it?

A French transposition of the EPBD directive

Decree No. 2020-887 of 20 July 2020, issued pursuant to Article 175 of the ELAN Act (Articles L. 173-1 et seq. of the French Construction and Housing Code), transposes into French law the European Directive 2018/844/EU on the energy performance of buildings (EPBD, Energy Performance of Buildings Directive). The application order of 8 October 2020 was amended by the order of 8 March 2022, then thoroughly overhauled by the order of 27 March 2025 (entered into force on 1 July 2025), which aligns France with the European Union's 2030 climate ambitions.

What the text says (CCH, Article R. 173-3)

"A building automation and control system is a system comprising all the products, software and engineering services for the automatic control, monitoring and optimisation of the energy consumption of the building's technical equipment."

This definition covers four minimum functions:

1. Monitoring: continuous tracking of consumption and the state of technical equipment;
2. Control: automatic regulation of heating, reversible air conditioning, ventilation and lighting;
3. Energy optimisation: GTB algorithms, self-learning, prediction;
4. Reporting: production of alerts, dashboards and energy performance indicators exportable to OPERAT.

The obligation applies to the owner, failing that to the holder of a real right (usufructuary, long-term leaseholder), and failing that to the occupant (Article R. 173-3, al. 2). In a tertiary condominium or multi-tenant building, it is therefore the landlord owner who carries the legal responsibility for bringing the building into compliance — with a duty to inform the tenant via an environmental annex to the lease.

Official 2025-2030 schedule

Date	Obligation
8 October 2020	Publication of the initial order (290 kW threshold)
8 March 2022	First amending order (threshold lowered to 70 kW)
1 July 2025	Entry into force of the 27 March 2025 order
1 January 2026	Class A BACS mandatory — 70 kW threshold (tertiary)
1 January 2028	Threshold lowered to 30 kW
1 January 2030	Threshold lowered to 10 kW — alignment with the -40% tertiary decree objective
30 September 2026	Deadline for OPERAT declaration of 2025 consumption

The 4 BACS classes of the NF EN ISO 52120-1 standard

The NF EN ISO 52120-1:2022 standard ("Energy performance of buildings — Contribution of building automation, control and building management systems") classifies BACS into four levels (A, B, C, D), with an increasing TEBacs (Technical Energy efficiency factor for Building Automation and Control Systems):

Class	Description	TEBacs	Estimated HVAC savings
D	No automation, local regulation only (independent room thermostats)	0	0%
C	Standard BACS, automatic HVAC regulation, time scheduling, occupancy scenarios	0.20	5-10%
B	Interoperability, centralised supervision, fault detection, terminal controllers per zone	0.40	15-20%
A	High-performance BACS, smart GTB, self-learning, predictive, Smart Grid interfacing	0.70	25-35%

Functions required by class A

The table below summarises the functions expected by class. To achieve class A (mandatory in France), your GTB must cover all class B functions, plus continuous optimisation functions, self-learning, advanced drift detection and Smart Grid / RES interfacing:

BACS Function	D	C	B	A
Automatic heating regulation	✗	✓	✓	✓
Time scheduling / occupancy scenarios	✗	✓	✓	✓
Terminal regulation (by zone / loop)	✗	✗	✓	✓
Centralised supervision	✗	✗	✓	✓
Fault detection and alarms	✗	✗	✓	✓
Interoperability (open protocols)	✗	✗	✓	✓
Continuous real-time optimisation	✗	✗	✗	✓
Prediction / self-learning	✗	✗	✗	✓
Smart Grid / RES interfacing	✗	✗	✗	✓

Who is concerned, who is exempted?

Cases of obligation

Article 1 of the 27 March 2025 order targets all tertiary-use buildings whose combined nominal useful power of heating, air conditioning or DHW production equipment is ≥ 70 kW:

• Offices (open space, coworking spaces, headquarters) — heavily affected: a 100 kW reversible heat pump alone covers the threshold;
• Retail (large stores, shopping centres) — +100 kW air conditioning is common;
• Hotels and outdoor hospitality (4★ and above) — DHW production + reversible air conditioning generally exceed 70 kW from 30 rooms;
• Healthcare facilities (hospitals, clinics, nursing homes) — redundant HVAC and DHW;
• Education (universities, high schools, grandes écoles) — mixed gas boiler + reversible air conditioning;
• Logistics and data centres (from 200-300 m²) — cooling power always > 70 kW;
• Restaurants, central kitchens, industrial laundries — DHW + commercial refrigeration.

Exemption cases (Article R. 173-3 of the CCH)

The 27 March 2025 order introduces several exemption cases:

• Installed power below the threshold (70 kW in 2026, 30 kW in 2028, 10 kW in 2030);
• Buildings whose seasonal use does not exceed 8 weeks per year (holiday residences, boarding schools);
• Very low-consumption buildings: annual consumption < 25% of an equivalent reference building;
• Installation cost higher than the expected energy savings over the lifetime (mandatory cost-benefit study);
• Existing buildings undergoing equipment replacement: obligation triggered only if the replacement amount exceeds 25% of the total replacement value of the installation (50% for insulation) — this is the non-regression principle of Directive 2018/844.

BACS and tertiary decree: two complementary decrees

A means obligation + a result obligation

The BACS decree and the tertiary decree (No. 2019-771) are complementary and inseparable:

• BACS decree: means obligation — install a class A GTB, regardless of the level of performance achieved;
• Tertiary decree: result obligation — achieve quantified reduction targets in consumption by 2030 (-40%), 2040 (-50%) and 2050 (-60%), declared on the OPERAT platform of ADEME.

A class A BACS is not a guarantee of meeting the objectives of the tertiary decree, but it is an operational prerequisite: the GTB provides the metering data, performance indicators and optimisation levers essential to OPERAT monitoring.

Directive 2018/844 (EU)
        │
        ▼
ELAN Act (2018) — art. 175
        │
        ▼
Decree No. 2020-887 (20/07/2020) — art. R. 173-1 to R. 173-5 of the CCH
        │
        ▼
Order of 08/10/2020 (amended 08/03/2022, then 27/03/2025)
        │
        ├──► Class A BACS ──► GTB ──┐
        │                              ├──► Tertiary decree
        │                              │     (No. 2019-771)
        └──► HVAC / Lighting / DHW ────┘            │
                                                   ▼
                                              OPERAT / ADEME

For further details, see our complete guide to the 2026 tertiary decree which details the HVAC obligations, the digital certificate from 1 July 2026 and the OPERAT declaration of 30 September 2026.

Penalties in case of non-compliance

Penalties specific to the BACS decree

Non-compliance with the BACS decree is punishable by an administrative fine of €1,500 per building (Article L. 173-2 of the CCH), doubled in case of recurrence. The competent authority is the préfet (DREAL) who can issue a formal notice with a deadline for compliance.

Cumulative penalties of the tertiary decree

Non-compliance with the tertiary decree also exposes you to:

• A formal notice from the DREAL or the préfet;
• An administrative fine of up to €1,500 per building (Article L. 174-1 of the CCH);
• A daily penalty in case of non-execution;
• Inclusion in the OPERAT dashboard made public — with a strong image risk for listed real estate companies and national brand operators.

The 4 technical functions of a class A BACS

To achieve the TEBacs of 0.70 of class A, the GTB must simultaneously fulfil the four functions defined by Article R. 173-3 of the CCH, with a higher level of requirement than class B:

1. Monitoring: meters and sensors by use

Instrumentation is the foundation of a class A BACS. Without reliable measurement points, no algorithm can optimise anything. The recommended measurement points are:

• Thermal energy meters (kWh of cooling and heat) on each production and distribution HVAC loop;
• Supply/return temperature sensors on each network;
• Outside temperature sensors and reference indoor temperature sensor (at least one per thermal zone);
• CO₂ and hygrometry sensors for ventilation modulation (variable flow according to occupancy);
• HVAC electricity sub-meters and DHW sub-meters;
• Heat meters on energy recovery loops and solar panels if any;
• Window opening detection (dry contact or CO₂ sensor) for night free cooling.

2. Control: terminal regulation by zone

Terminal regulation by loop or zone is one of the key functions of class B (and therefore of class A). It requires motorised 2- or 3-way valves on each terminal loop, variable frequency drives on fans and pumps, and room-by-room (or zone-by-zone) regulation in cooling as in heating mode. For reversible air-air air conditioning systems (wall split, cassette, ducted), regulation is done via the remote thermostats or centralised remote controls of the indoor unit.

3. Optimisation: self-learning algorithms

This is the major difference between class B and class A. The continuous optimisation algorithms use the collected data to:

• Adapt setpoints based on actual occupancy (presence detectors, badge readers, Outlook schedule);
• Anticipate free gains (sunshine, occupancy) and pre-cool or pre-heat during off-peak hours;
• Detect drifts (clogged filters, stuck valves, dirty condenser) by data correlation;
• Coordinate producers (reversible heat pump + gas boiler + solar thermal) according to the most cost-effective energy mix at time t;
• Interact with the electricity grid (Tempo tariff signal, spot market, smart grid) to shift consumption to less carbon-intensive hours.

4. Reporting: automated export to OPERAT

The 27 March 2025 order requires the BACS to produce exportable energy performance indicators. For buildings subject to the tertiary decree, export must be done automatically to OPERAT (secure REST API or quarterly CSV export). This automation avoids annual re-entry, makes the declaration reliable before 30 September 2026 and constitutes an element of proof of compliance in case of DREAL inspection.

Case study: a 2,800 m² office building in Boulogne-Billancourt

Context

A law firm of 110 people occupies a tertiary building of 2,800 m² over four floors, in zone H1 (Île-de-France). The installed HVAC power totals 215 kW:

• 2 Daikin Altherma 3 H HT reversible air-to-water heat pumps of 70 kW each (heating + cooling);
• 1 dual-flow air handling unit (AHU) of 50 kW for meeting rooms;
• Collective DHW production of 25 kW.

Before the works, regulation was done via independent room thermostats and time schedulers: the GTB was non-existent (class D).

The compliance project

Proclimo completed in 6 months (audit + works + commissioning):

• Initial energy audit: temporary instrumentation (current sensors, Pt100 sensors, network analyser) for 4 weeks;
• GTB architecture master plan: BACnet/IP network as backbone, KNX gateways for terminal controllers, LoRaWAN for wireless sensors;
• Migration of 14 terminal controllers to KNX Schneider SpaceLogic communicating controllers;
• Installation of a Siemens Desigo CC supervision with 3 BACnet Advanced controllers;
• Installation of 8 thermal energy sub-meters (1 per terminal loop) and 12 CO₂ sensors in meeting rooms;
• Self-learning module activated on the heat pumps: adaptation of the heating curve and cooling setpoint according to the weather (Météo France API) and occupancy (badge readers);
• OPERAT connector activated with automated quarterly export.

Results after 9 months of operation

• Class A achieved: third-party audit confirming a TEBacs of 0.71 (AFNOR Certification audit);
• HVAC savings: -32% on the heating + air conditioning bill (from €78,000 ex. VAT/year to €53,000 ex. VAT/year);
• Thermal comfort: 65% reduction in complaints (from 23/month to 8);
• Gross payback time: 6.2 years (investment €145,000 ex. VAT, CEE BAT-TH-116 premium of €18,000 deducted);
• Tertiary decree compliance: 2030 trajectory secured, the building is targeting -47% compared to 2017;
• OPERAT reporting: automated quarterly export, zero manual reprocessing.

The investment amounted to €145,000 ex. VAT, of which €18,000 CEE premium (sheet BAT-TH-116 "Class A or B GTB"). The gross payback time is 6.2 years, for a GTB lifespan exceeding 15 years.

How much does BACS compliance cost in 2026?

Indicative budget (ex. VAT, installation and instrumentation included)

Tertiary building size	HVAC power	GTB architecture	Investment	Annual savings	Gross ROI
Small shop 200-400 m²	30-50 kW (2028 renovation)	Class B (preparation)	€12,000-25,000	€2,500-4,500	4-7 years
Office 800-1,200 m²	70-120 kW	Class A GTB BACnet/KNX	€45,000-90,000	€6,000-12,000	5-8 years
Office building 2,000-3,500 m²	150-280 kW	Class A GTB multi-protocol	€90,000-180,000	€14,000-28,000	5-8 years
4★ hotel 4,000 m²	250-400 kW	Class A GTB + heat recovery	€180,000-320,000	€35,000-55,000	4-7 years
Hospital / clinic 8,000 m²	600+ kW	Class A GTB + GTC + R2S cybersecurity	€350,000-700,000	€80,000-150,000	4-7 years

Factors that vary the ROI

1. The existing GTB level: a class C building (simple regulation) requires an investment 2 to 3 times lower than a class D building (no GTB).
2. The quality of instrumentation: thermal energy meters and CO₂ sensors in sufficient numbers divide the payback time by 1.5.
3. The chosen protocol: closed proprietary buses (sold 10 years ago) often require complete replacement; open protocols (BACnet, KNX, Modbus) allow a software-only upgrade.
4. Pooling: a project combining GTB + reversible heat pump + solar thermal + storage maximises the GTB usage rate and shortens ROI to 4-5 years.
5. Cumulative aid: CEE BAT-TH-116 (up to €30 ex. VAT/m²), MaPrimeRénov' Tertiaire, ADEME heat fund (public tertiary), regional aid (Île-de-France, PACA, Auvergne-Rhône-Alpes).

Stackable financial aid in 2026

For businesses and private tertiary

• CEE BAT-TH-116: premium for the installation of a class A or B GTB compliant with NF EN ISO 52120-1. Typical amount: €10 to €30 ex. VAT/m², i.e. €15,000 to €50,000 for a 1,500 m² building. Bonus possible if the GTB enables a 30% reduction in HVAC consumption.
• CEE BAT-TH-113 (reversible heat pump): stackable if you replace an old boiler with a RGE reversible heat pump in the same project.
• CEE BAT-TH-145 (insulation): for the insulation of HVAC distribution networks.
• Éco-PTZ tertiaire: zero-interest loan up to €50,000 for a bundle of works including the GTB and the reversible heat pump.
• Corporate energy transition tax credit (integrated into the 2026 budget).

For public tertiary and condominiums

• ADEME heat fund: investment aid for public tertiary projects exceeding 100 kW thermal, 30 to 50% subsidy;
• Regional grants (Île-de-France, PACA, Occitanie, Auvergne-Rhône-Alpes): additional aid of 10 to 20% of the GTB extra cost;
• ACTEE programme (Action Collectivités pour la Transition Énergétique): supports local authorities via calls for projects dedicated to GTB and energy audit.

BACS and cybersecurity: the regulatory point

With the generalisation of connected GTB, the cyber risk has become a regulatory issue. The RE2020 and the R2S label (Ready to Services) now impose specific requirements for new buildings and major renovations:

• Network segmentation: the GTB must be isolated from the office network (dedicated VLAN, industrial firewall);
• Strong authentication: no unauthenticated remote access (VPN, certificates, 2FA);
• Data encryption: TLS 1.3 minimum for BACnet/IP, KNXnet/IP, MQTT flows;
• Logging and audit: access logs retained for at least 3 years;
• OTA software updates: minimum quarterly cadence, with prior testing on a test bench;
• Continuity plan: in case of incident, local degraded mode (autonomous controller regulation) without service interruption.

Proclimo systematically integrates these best practices into its class A GTB deployments, relying on hardened controllers (Siemens, Schneider, ABB) and a partner SOC for 24/7 supervision.

Maintenance and software updates: the Annex III obligation

Annex III of the 8 October 2020 order as amended specifies that the BACS must be designed to allow:

• Measurement, recording and analysis of the energy consumption of technical equipment;
• Triggering of alerts in case of abnormal operation;
• Software updating at least annually;
• Cyclic testing of BACS functions (regulation, alarms, reporting) on an annual basis.

Proclimo offers a class A GTB contract with:

• 24/7 monitoring from a supervision centre based in Île-de-France;
• OTA updates quarterly (controller firmware, supervision, optimisation modules);
• Annual energy audit with performance report and action plan;
• Cyclic testing of BACS functions in April (before the hot season) and October (before the cold season);
• Automated OPERAT reporting, quarterly export.

Choosing the right GTB integrator

Qualifications to check

For class A BACS compliance, require the following qualifications from your integrator:

• RGE studies (if the energy audit is CEE-eligible);
• KNX Partner or BACnet Advanced qualification for multi-protocol integrators;
• Refrigerant capacity certificate (category 1 minimum) for the HVAC part;
• ISO 27001 certification or France Cybersecurity label for cybersecurity aspects;
• Decennial insurance covering the GTB ("building automation" activity).

The 7 questions to ask your integrator

1. "What TEBacs are you targeting and what self-learning algorithms do you offer?"
2. "Is the protocol open (BACnet ISO 16484-5, KNX ISO/IEC 14543) or proprietary?"
3. "Is the OPERAT connector included in the offer or billed as an option?"
4. "What is the lead time between order and OPERAT declaration?"
5. "Are software updates included in the maintenance contract?"
6. "What is the cost of a later extension (adding a loop, a meter, a zone)?"
7. "Do you offer an energy performance guarantee (EPG) on the 25% savings announced?"

Take action with Proclimo

Proclimo, an RGE installer and multi-protocol GTB integrator (BACnet, KNX, Modbus, LoRaWAN, MQTT) in Île-de-France, supports owners, property managers, tertiary condominium trustees and operators in their BACS compliance, tertiary air conditioning and energy renovation projects. Our integrated offering covers audit, sizing, installation and maintenance over 15 years.

• Energy audit and existing GTB audit: 4-week temporary instrumentation, identification of classes B/C/D, compliance action plan and estimate of CEE BAT-TH-116 aid.
• Class A GTB installation: BACnet/KNX multi-protocol architectures, thermal energy meters, CO₂ and hygrometry sensors, Desigo CC / EcoStruxure / Niagara supervision, self-learning module, OPERAT connector. Commissioning and guaranteed performance tests.
• Class A GTB contract: 24/7 monitoring, quarterly OTA updates, annual energy audit, cyclic testing of BACS functions, automated OPERAT export.
• Urgent GTB repair 7 days/7: intervention within 24 to 96 hours in Île-de-France on all types of GTB and HVAC controllers, all protocols.

Contact Proclimo for a free BACS audit of your tertiary building, or book your audit online. Our team operates in Île-de-France (75, 77, 78, 91, 92, 93, 94, 95) and supports your projects in compliance with the 2026 tertiary decree, the 2026 RGE reform, the reversible heat pump bonus, the annual maintenance obligations and the 5.5% VAT on reversible air conditioning. To cool your home this summer, also see our guide to cooling a home without air conditioning during a heatwave and our comparison of air conditioning for offices and businesses.

Sources: Légifrance — French Construction and Housing Code, Articles L. 173-1 to L. 173-3 and R. 173-1 to R. 173-5 · Légifrance — Decree No. 2020-887 of 20 July 2020 on automation and control systems for tertiary buildings · Légifrance — Order of 27 March 2025 amending the order of 8 October 2020 (BACS) · Eur-Lex — Directive (EU) 2018/844 of 30 May 2018 (EPBD) · AFNOR — NF EN ISO 52120-1:2022 "Energy performance of buildings — BACS" · ADEME — OPERAT user guide 2024-2025 · CEREMA — POEPU 2023 study on GTB performance in tertiary · DGALN — BACS FAQ 2024-2025 · ATITA-BACS — Class A GTB practical guide 2024 · France Rénov' — Directory of RGE professionals · Ministry of Ecological Transition — Tertiary decree No. 2019-771 of 23 July 2019 · Construction Trades Observatory — Refrigeration and GTB trades 2026.