For buildings above 290 kW, the BACS decree deadline already passed on 1 January 2025. The postponement to 1 January 2030 only applies to the 70-290 kW bracket. One question is rarely asked: does your BMS tick the boxes on paper, or does it actually work? This article sets out a method to prepare, carry out and make use of a BACS audit with energy compliance in mind - from document collection to lower consumption in operation.
Regulatory framework and how a BACS audit unfolds
Which buildings are subject to the BACS decree?
The BACS decree targets non-residential commercial buildings whose heating or air-conditioning system, combined or not with ventilation, has a rated output power above a set threshold (art. R. 175-2 of the CCH, the French Construction and Housing Code). Since the BACS decree no. 2020-887 (French decree on building automation and control systems), buildings concerned above 290 kW had to have an automation and control system by 1 January 2025 (source: Légifrance, decree no. 2020-887). The 70 kW to 290 kW bracket is postponed to 1 January 2030. Each system (heating or air conditioning) is compared with the threshold individually, without adding heating and cooling together; however, the generators of a single system (boilers in cascade) are added up (ministry application guide, January 2026). A partial commercial use is enough to trigger the obligation once the threshold is exceeded. Actual consumption plays no part in this calculation: only the output shown on the nameplates counts.
Which timeline applies to your commercial portfolio?
The timeline has two tiers. Commercial buildings above 290 kW had to comply by 1 January 2025. Decree no. 2025-1343 of 26 December 2025 pushed back the obligation for the 70-290 kW bracket from 1 January 2027 to 1 January 2030 (source: Légifrance, decree no. 2025-1343). The periodic inspection must then be renewed at least every 5 years, and within 2 years of the system being installed or replaced (order (arrêté) of 7 April 2023, art. 5).
Did you know? The postponement to 1 January 2030 does not apply to new buildings: those whose building permit application was filed on or after 8 April 2024 (output > 70 kW) or 21 July 2021 (output > 290 kW) are subject to the requirement from construction (art. R. 175-2 CCH).
BACS decree and Décret tertiaire: two complementary approaches
The BACS decree sets an obligation of means: install and maintain an automation system able to control HVAC. The Décret tertiaire (France's tertiary decree on energy savings in commercial buildings, decree no. 2019-771) sets an obligation of results: cut consumption by 40% by 2030, 50% by 2040 and 60% by 2050 for buildings with more than 1,000 m² of floor area (source: Légifrance, decree no. 2019-771). A building that complies with the BACS decree can still fail on energy performance. Conversely, a frugal building without an automation system does not meet the regulations in force. The two requirements coexist; neither replaces the other.
Document collection and audit preparation
A poorly prepared BACS audit means endless back-and-forth. The document review should gather at least:
- DOE (as-built documentation file)
- HVAC diagrams (schematics and controls)
- Current BMS maintenance contracts
- Consumption history over 2-3 years
- Building permit (to check the filing date)
- CEE energy-savings certificate sheets already filed (BAT-TH-116 where applicable)
- Controller installation records
Every document missing from the collection lengthens the time needed to produce the final report.
Technical visit and on-site verification
The inspector physically checks how the system operates. They check the condition of the controllers, test sequences from the supervisory system and list active overrides. Temperature sensors and motorized valves are part of the inspection. The order of 7 April 2023 specifies that the visit takes place on a running installation and covers the accessible parts of the BACS and technical systems; the assessment checks in particular hourly metering per functional zone, data analysis, effective adjustment in case of drift, five-year data retention, manual shutdown and interoperability (source: Légifrance, order of 7 April 2023, art. 3 and annex 3). The texts set no specific qualification for the inspector, but the report must bear their name and signature (annex 5).
Writing the report: content and timeframe
The BACS audit report records compliance by control family. It identifies gaps, makes recommendations and proposes a prioritized action plan. Follow-up of non-conformities is detailed with a correction schedule. The analysis covers the functions that actually work - not only those declared at handover. The report is a reference document to be kept for 10 years and made available in the event of an inspection.
How often must the inspection be renewed?
The steps of a BACS audit
From the initial inventory to the action plan: each phase of the diagnosis of your building automation and control systems.
☞ Click a step to see the details
The auditor lists all BACS equipment in place: controllers, field controllers, sensors (temperature, occupancy, pressure), actuators, supervisor. Each HVAC subsystem (heating, ventilation, air conditioning) is identified with its communication protocol (BACnet, LON, Modbus).
The result is a technical map describing the existing architecture, the controlled points and the areas not covered.
Each control sequence is scrutinized: weather-compensation curves, heating curves, time schedules, demand-controlled ventilation. The auditor checks that programmed setpoints and actual operation match.
Drifts are documented: equipment running outside occupied hours, unsuitable setpoints, unstable control loops or loops stuck in manual override.
The auditor assigns the BACS efficiency class (A, B, C or D) according to EN 15232, function by function: heating, cooling, ventilation, lighting. Each function is assessed on the level of automation and management actually in service.
A building in class D has no automation; in class C, it has basic control. The decree imposes no class: the ministry application guide (January 2026) states that class C is deemed compliant; class B is often targeted to go further and qualify for CEE certificates.
Consumption history (electricity, gas, district heating) is cross-checked with occupancy data, weather (heating degree days, HDD) and load curves. The aim: quantify the excess consumption attributable to poor control.
This step separates what is a control problem (fixable through the BMS) from what requires work on the equipment itself.
The auditor quantifies each savings opportunity: optimization of time schedules, setpoint adjustments, replacement of obsolete controls, implementation of advanced functions (free cooling, night setback, load shedding).
Each action is ranked by return on investment and by implementation complexity. Savings are estimated in kWh/year and as a percentage of the energy bill.
The final report consolidates the whole diagnosis: technical baseline review, current BACS class, regulatory gaps identified and a roadmap to reach the target class.
The action plan is structured over 3 horizons: immediate actions (reprogramming, correcting drifts), short-term actions (moving up a BACS class) and structural investments (BMS upgrade, integration of advanced functions). Each action is costed in cost, estimated savings and lead time.
Sources: EN 15232-1 standard, BACS decree 2023, feedback from BMS audit assignments in commercial buildings
The BACS inspection must be renewed at intervals not exceeding 5 years (source: Légifrance, article R. 175-5-1 of the CCH and article 5 of the order of 7 April 2023). This is brought forward to two years after the installation or replacement of the BACS, or of one of the technical systems connected to it - replacing a generator or adding an AHU, for example. The texts provide no exemption from this frequency. Planning the renewal ahead avoids discovering drifts that have built up over five years without any check.
BACS audit, BMS audit, energy audit: three approaches not to be confused
Scope and regulatory trigger of each approach
The BACS audit checks that the automation system complies with the functional requirements of the decree. Its scope is regulatory: applicability, functions and consumption monitoring. The BMS audit is a voluntary technical diagnosis. It assesses the condition of the management system - obsolescence, controller reliability, upgradability. The energy audit gives an overall picture of consumption. It is mandatory every 4 years for companies whose average annual final energy consumption reaches 2.75 GWh and which have no certified energy management system (source: Légifrance, Energy Code (Code de l'énergie), article L. 233-1, as amended by Law no. 2025-391 of 30 April 2025, in force since 1 October 2025; the former headcount and turnover criteria no longer apply). A favorable BACS diagnosis says nothing about overall energy efficiency. An energy audit does not check control functions.
Expected deliverable and the right contact
Each assignment leads to a separate deliverable. The BACS audit produces a compliance report structured by control family. The BMS audit delivers a classification of the system's condition with an upgrade plan. The energy audit provides a costed action plan covering the building envelope and energy uses. The BACS inspection is carried out at the owner's initiative by an inspector for whom the texts require no specific qualification. BMS support is provided by an independent BMS advisor. The energy audit requires a certified engineering consultancy.
Where to start, depending on your situation?
What each assignment covers, what it produces and who carries it out
| Criterion | BACS audit | BMS audit | Energy audit |
|---|---|---|---|
| Scope | Compliance of the automation system with the functional requirements of the BACS decree | Actual condition of the building management system: obsolescence, reliability, upgradability | Overall review of the building's consumption (envelope + uses) |
| Trigger | Regulatory: decree no. 2020-887 (290 kW / 70 kW thresholds) | Voluntary: decision by the building owner | Regulatory: Energy Code, art. L. 233-1 (companies consuming ≥ 2.75 GWh/year of final energy, every 4 years) |
| Deliverable | Compliance report structured by control family (heating, air conditioning, ventilation, consumption monitoring) | Classification of the system's condition + upgrade plan | Costed action plan covering the envelope and uses |
| Contact | Inspector appointed by the owner (no qualification imposed by the texts) | BMS advisor independent of the design engineer | Certified engineering consultancy |
| Frequency | At least every 5 years, 2 years after an installation (article R. 175-5-1 of the CCH, order of 7 April 2023) | One-off or when changing contractor | Every 4 years |
| How they fit together | Does not check overall energy performance | Paves the way for the BACS inspection | Does not cover control functions |
BACS diagnosis first
First confirm applicability (rated output power of the heating or air-conditioning system). Then estimate what installing a BMS represents in cost and lead time. The BACS diagnosis frames the scope before any investment.
Sources: Légifrance (decrees no. 2020-887, no. 2019-771), Energy Code art. L. 233-1
The answer depends on your portfolio. The widget below compares the three approaches and points you in the right direction for your case.
A building without a BMS should first go through a BACS diagnosis. The aim: confirm applicability and estimate the cost and lead time of deploying a BMS.
A building with a BMS in place is better off starting with a BMS audit. If the system is riddled with manual overrides or disconnected meters, the BACS inspection will only record predictable gaps. Better to get the BMS back in working order before the regulatory inspection.
A new building at handover builds the BACS inspection into the handover process itself. The diagnosis and the clearing of technical defects are handled in parallel.
BACS inspection vs BMS obsolescence audit: two views of the same building
The BACS inspection is a periodic regulatory check. It verifies that the automation system complies with the requirements of the decree - no more, no less. Its outcome is binary: compliant or non-compliant.
The BMS obsolescence audit takes a broader technical view. It assesses the remaining service life of the controllers, the availability of spare parts, compatibility with current protocols and the system's ability to evolve. A building can be compliant while being run by a supervisory system at end of life. The first approach tells you whether you are within the rules. The second tells you how long it will last. Our "Obsolete" BMS audit covers this second aspect.
What is checked during a BACS audit?
The checkpoints of the order of 7 April 2023
The 4 families of points in a BACS audit
Click each family to explore the checkpoints involved
An audit compliant with the BACS decree inspects 4 main families of functions of the automation system. Each one targets a different energy efficiency lever.
A complete BACS audit covers all 4 families to determine the BMS class achieved (A, B, C or D according to EN 15232).
Sources: EN 15232-1:2017 standard, BACS decree no. 2020-887, ADEME 2024
The order of 7 April 2023 structures the BACS inspection around three parts: the document check (annex 2), the assessment of the requirements of article R. 175-3 for each connected use - heating, cooling, ventilation, domestic hot water, integrated lighting, on-site electricity generation (annex 3) - and the recommendations (annex 4) (source: Légifrance, order of 7 April 2023). The order sets no class "level" per use: it checks that the automation system meets the functional requirements of the decree. The control functions detailed below (time scheduling, interlocking, free cooling...) belong to a thorough BMS audit, not to a literal requirement of the text.
| Point checked (annex 3) | What the inspector checks | Requirement of the decree (R. 175-3 CCH) |
|---|---|---|
| Functional zones and metering | Identification of zones, presence and proper operation of production and consumption meters, per zone and at an hourly time step | Continuous monitoring and recording |
| Analysis and adjustment | Analysis devices able to detect losses of efficiency and inform the operator, and effective adjustment of systems in case of drift | Drift detection and adjustment |
| Trend logging | Recording and retention of data at monthly granularity for five years | Five-year retention |
| Manual shutdown and interoperability | Ability to shut down manually and to manage connected systems autonomously, interoperability of the BACS | Interoperability, autonomous management |
Heating control: the points checked
The system must manage temperature setpoints per zone. The functions checked:
- Time scheduling matched to occupancy
- Open-window detection with automatic shutoff
- Heating shut off outside occupied periods
- Setpoints lowered when unoccupied (setback or frost protection)
These points determine the energy savings achievable on the hot water loop. The configuration of each zone is the foundation of compliance.
Air-conditioning control: the points checked
On the cooling side, the inspection covers separate functions:
- Temperature setpoints per zone with an adjustable minimum deadband
- Heating/cooling interlock to prevent the building from heating and cooling at the same time
- Free cooling: using outdoor air when its temperature allows
Cooling production for air conditioning is often the most volatile item. A faulty interlock can wipe out the savings delivered by control.
Consumption monitoring and trend logging
This is the family that fails most often in operation. The metering plan often exists on paper, but the meters report nothing to the supervisory system.
Expert tip Check that every meter is connected to the supervisory system and that the usable history covers at least 12 months without data gaps. A meter that is installed but not logged proves nothing during the inspection.
Management of drift alerts completes the setup. Without properly configured thresholds, consumption drifts without anyone noticing.
How is the class of your BMS assessed?
NF EN ISO 52120-1 defines four BMS classes: class A (the most efficient), class B, C and D. The BACS decree does not explicitly mention a class. It sets functional requirements by family. The prevailing reading in the market remains "class B minimum".
An often overlooked point: a building's class is that of its weakest function. If heating reaches class A but ventilation is stuck in class C, the building is rated C. Compliance hinges on the weakest link. For more on classification, see our article on the real class of your BMS.
From the field checklist to performance in operation
10 points to check before starting the inspection
Rated output power per HVAC package
Risk: without the output of each system, applicability to the decree cannot be confirmed
List of controllers and protocols in place
Risk: an unidentified controller is a blind spot for the inspector
Status of the supervisory system (accessible and working)
Risk: a supervisory system that is switched off makes it impossible to check control sequences
Consumption history over at least 12 months
Risk: data gaps invalidate any demonstration that monitoring is compliant
Current BMS maintenance contract
Risk: without a contract, preventive maintenance is not tracked
Outstanding handover defects
Risk: open defects mean commissioning was never completed
List of active overrides (manual overrides)
Risk: each override skews the compliance reading during the inspection
Up-to-date HVAC schematics
Risk: outdated schematics slow down the technical visit and the report
CEE sheets already filed (BAT-TH-116)
Risk: without a CEE history, you lose traceability of the class achieved
Building permit (filing date)
Risk: the filing date determines whether the building benefits from the postponement to 1 January 2030
Rated output power and HVAC scope
The first step before any BACS audit: record the rated output power of each heating system and each air-conditioning system. Each system is compared with the threshold individually, without adding heating and cooling together, but the generators of a single system (boilers in cascade) are added up (art. R. 175-2 of the CCH; ministry application guide, January 2026). Domestic hot water and stand-alone ventilation are not included in the applicability calculation. If one of these systems exceeds 290 kW, the building is already subject to the decree. Between 70 and 290 kW, the deadline is 1 January 2030. Every commercial part of the building falls within scope once the overall threshold is exceeded.
Controllers, protocols and status of the supervisory system
Second point: take an inventory of the automation system in place. Which controllers run the HVAC? Do they work over BACnet, LonWorks or a proprietary bus? On a Johnson Controls Metasys estate, for example, the legacy N2 bus and the native BACnet of the NAEs often coexist in the same building. Is the supervisory system accessible from a dedicated workstation, or is it sitting on a server nobody looks at?
A BMS whose supervisory system can no longer be queried cannot be inspected properly. Identifying unconnected points avoids nasty surprises on inspection day. The operator in charge of the building must provide working access to the platform.
Consumption history and metering plan
The metering plan must cover every significant energy use in the commercial premises. Check that trend logging actually works: data gaps of several weeks invalidate any analysis.
Data collection must make it possible to separate heating from air conditioning and ventilation. Without this granularity, compliance by family cannot be demonstrated during commissioning. Monitoring requires continuous usable data over at least 12 months.
Overrides, degraded modes and handover defects
Each active override skews the compliance reading. The inspection does not see normal operation but a degraded mode frozen for months. Outstanding handover defects raise the same problem: commissioning was never completed.
Listing overrides before the audit makes it possible to tell a temporary operating choice from a sign of malfunction. Setting up a register takes little time and changes everything.
Can a compliant BMS be unusable?
Anatomy of a BMS supervision graphic
Explore the functional layers of a supervisor by clicking each component
A BMS supervisor centralizes data feedback and the control of a building's technical equipment. Here are the layers visible on a typical graphic, in line with EN ISO 52120-1 (formerly EN 15232).
The supervisory system displays each control loop: setpoint, measurement, valve/damper output, mode (comfort, setback, frost protection). A measurement/setpoint deviation greater than 2 °C for 30 min triggers an alarm.
In class C or B (EN ISO 52120-1), control includes zone-level control and an individual time schedule per terminal unit.
The energy graphic shows the main meters (electricity, gas, chilled water, district heating) and the sub-meters per use: HVAC, lighting, process, power outlets.
A rolling 24-month history makes it possible to compare weather-corrected consumption (HDD) and detect out-of-threshold consumption drifts.
The supervisor centralizes alarms by criticality level: urgent (equipment shutdown, critical temperature), major (setpoint drift, sensor fault), minor (preventive maintenance).
A BACS audit checks that alarms are handled within the required timeframes: acknowledgement rate, mean time to resolution, ratio of active alarms to supervised points.
Time schedules define occupancy periods per zone: comfort, setback, off. They drive HVAC, lighting and ventilation together.
A BACS audit checks the consistency between programmed schedules and actual occupancy and checks that there are no permanent manual overrides bypassing the automation.
The supervisor communicates with the controllers through standard protocols: BACnet IP/MSTP, Modbus TCP/RTU, LonWorks, KNX. The network view shows the status of each controller.
The audit checks network coverage: percentage of equipment actually reporting to the supervisor, communication latency and unconnected "orphan" points.
Sources: EN ISO 52120-1:2022 standard (BACS classes A-D), RAGE BMS guide 2024, field feedback from BMS operators
On paper, the BMS has been delivered. Handover is signed. The report mentions class B. On site, the supervisory system runs on a PC nobody has switched on for six months. 200 active alarms pile up unhandled. Permanent overrides on the AHUs prevent any automatic control. Three meters out of ten report data.
This installation complies with the BACS decree in the strict sense. It controls nothing. Installing a BMS is only worth it if someone operates it.
Regulatory compliance and CEE eligibility: two separate logics
Passing the BACS audit does not automatically trigger CEE certificates. Standard sheet BAT-TH-116 makes the award of energy-savings certificates conditional on installing a class A or B system according to NF EN ISO 52120-1 (source: French Ministry for the Energy Transition). The BACS decree sets its own functional requirements without explicitly imposing a class. Regulatory compliance and CEE funding coexist without being the same thing.
What making a BMS reliable means in practice
Making the existing BMS reliable means working on what malfunctions after the initial installation. Removing permanent overrides. Realigning sequences with actual needs. Bringing disconnected meters back into service. Clearing the backlog of alarms. Checking that preventive maintenance covers the controllers and not only the HVAC equipment.
The payback time of a reliability upgrade is often shorter than that of a full replacement. The improvement applies to what is already there, without changing hardware. This lean approach avoids over-equipping a building that above all needs to be operated properly.
What Foobot brings to your BACS audit
An independent advisory view, separate from the contractor selling the installation
The Foobot team works as a BMS advisor on the building owner's side, not the vendor's. The difference is structural: whoever installed the BMS has no interest in flagging their own shortcomings. Independent support changes the nature of the BACS audit.
Expert tip The most common conflict of interest: asking the BMS integrator to assess their own work. The need for a third-party view arises as soon as the compliance report commits a renovation budget.
Make your BMS reliable before chasing compliance
The approach starts with an on-site review of the existing BMS. Before aiming for compliance with the BACS decree, the team checks that the system actually works: are the sequences consistent? Do the meters report usable data? Are overrides documented? Making the system reliable first avoids box-ticking compliance. Optimizing HVAC control improves the measured results before the inspection.
Measuring savings after compliance work
Once the BMS is reliable, energy savings are measured using the IPMVP protocol with weather correction based on heating degree days (HDD). This method makes the results auditable by an independent third party. At the Valeo site, a 28.6% reduction in HVAC consumption was measured using this protocol (source: Valeo case study).
The analysis separates claimed savings from verified savings. For buildings at handover and in the GPA warranty year, this rigor makes the difference between compliant use and high-performance use.
From compliance to control: when AI takes over
In buildings whose HVAC complexity justifies it, a reliable BMS becomes the foundation for predictive AI control. The digital twin controls HVAC every 15 minutes, 24/7, through the existing BMS. Implementation requires no hardware replacement. If a simple sequence is enough, Foobot says so. AI is not a default option: it is a lever for buildings where response time and thermal inertia go beyond what a time schedule can handle.
The 5 key steps to bring your building into compliance
Explore each phase by clicking the steps below
The BACS decree requires commercial buildings to be equipped with an automation and control system by 2025 or 2030 depending on installed HVAC output. Here is the typical pathway to get there.
Sources: decree no. 2020-887 (BACS decree), EN 15232 standard, ADEME 2024
FAQ - BACS audit
By what date must my installation meet the requirements of the BACS decree?
Commercial buildings whose heating or air-conditioning system exceeds 290 kW of rated output power had to comply by 1 January 2025. For the 70-290 kW bracket, the BACS decree postpones the deadline to 1 January 2030 (decree no. 2025-1343).
How does a BACS decree audit unfold?
The audit follows three steps: document collection, on-site inspection of the building automation and control system, then writing of the report. The diagnosis covers the four families of functions. The report is delivered within one month of the visit.
Is a BACS enough for the Décret tertiaire?
No. The BACS decree sets an obligation of means. The Décret tertiaire (France's tertiary decree on energy savings in commercial buildings) sets a target result: a 40% cut in consumption by 2030. The OPERAT platform (the French government's consumption reporting platform) collects the declarations. A BACS helps reduce consumption but does not guarantee that the commercial sector thresholds will be met.
What does BACS mean? What is the difference between BACS and BMS?
BACS stands for building automation and control system. It is the standardized term for what France calls GTB (gestion technique du bâtiment), known in English as a BMS (building management system). Both refer to the automation system that controls HVAC. The difference is one of terminology, not function.
Which documents must be provided for a BACS audit?
DOE (as-built documentation file), HVAC schematics, building permit, maintenance contracts, consumption history and an inventory of the controllers in place. Collecting these documents determines the quality of the audit and reduces back-and-forth with the inspector.
Can mandatory energy audits determine the need for a BACS?
The energy audit identifies consumption items but does not cover the functions required by the BACS decree. It can reveal energy savings potential that the BACS will then capture. The two approaches complement each other in the commercial sector.
At what stages must checks be carried out when installing a BMS with CEE funding?
Deploying a BMS eligible for CEE energy-savings certificates involves a check before works (existing class), a check at handover (class A or B achieved) and post-installation monitoring. The BACS decree adds the periodic inspection every five years.
Should you start with a BACS decree audit or a BMS audit?
If your BMS is in place but nobody operates it, start with a technical diagnosis combined with an audit of the installation. This diagnosis makes it possible to fix malfunctions before the regulatory inspection.
Does the BACS decree provide for an exemption?
The BACS decree provides for an exemption if the payback period exceeds ten years. This exemption requires a documented technical and economic study. It remains exceptional: few commercial premises reach this threshold.
How does the building automation and control system work?
The system collects data from the sensors and sends it to the controllers, which adjust HVAC control in real time. Energy is controlled by zone. The building must have this system installed as soon as it exceeds the output thresholds.