Of the ten results on Google's first page, only one mentions the French BACS decree. Yet every Siemens Desigo management platform will have to prove its functional compliance by 2030 at the latest. Siemens documentation describes products. It says nothing about the real condition of your BMS in operation. This open platform for active management of smart buildings deserves a field-level breakdown: Desigo CC, Desigo Optic, PXC. Understand the architecture to improve real operation and meet the requirements of the French BACS decree. Gain operating comfort and energy savings.
From Landis & Staefa to PXC controllers: architecture and evolution of the Desigo range
Landis & Staefa, Desigo Insight and the birth of Siemens supervision
Siemens acquired Landis & Staefa in 1998 to create Siemens Building Technologies (Siemens AG, corporate history). The Desigo building management system range was born from this merger. Desigo Insight was the reference supervision platform for more than ten years. It is still present on many commercial sites in France. Integrating new components on this ageing base is a challenge: scarce parts, patchy documentation.
Desigo CC: supervision or hypervision?
Desigo CC goes beyond a simple HVAC supervisor. This multi-discipline BMS solution brings together heating, ventilation, lighting, fire safety and access control on a single user interface. It is hypervision in the strict sense. Version V9 strengthens cybersecurity and reporting through dedicated dashboards. This multi-discipline capability remains under-used on most of the sites we audit. Desigo CC Compact covers mid-sized buildings with the same software core. The scope goes well beyond a simple GTC (centralised technical management).
Desigo Optic: the new generation and the FIN framework
Desigo Optic is built on the FIN Framework and Haystack semantic tagging (siemens.com, product page). Its Edge2Cloud architecture sets it apart from CC: designed as cloud-native, accessible via a mobile app, not a mere upgrade. Haystack tagging standardises the tags of every BMS point. This new application is part of Siemens' Smart Building and Smart Infrastructure strategy. The Desigo building management system thus becomes easier to read for maintenance teams.
Did you know? Haystack tagging assigns standardised semantic tags to every BMS data point. A new technician understands the logic without reading 200 pages of documentation.
Desigo PXC: the programmable field controller
The layers of a Siemens Desigo CC architecture
Click on each level to explore its components, protocols and role in controlling the building
A Siemens Desigo CC BMS is organised in stacked layers, from the field (sensors, actuators) up to centralised supervision. Each level communicates with the others via standardised protocols.
The benefit of a standardised architecture (BACnet/IP): it lets you add an energy control layer on top of the existing supervision, without replacing the controllers or the field equipment already in place.
Sources: Siemens Building Technologies - Desigo CC documentation 2024, ISO 16484 standard (BACnet), ASHRAE Standard 135
The Desigo PXC is a native BACnet/IP field controller. It handles local control of heating and ventilation equipment - valves, dampers, fans - and sends data up to the supervision (siemens.com, PXC product sheet). Synco covers small standardised sites. The PXC targets complex environments: hospitals, head offices. Local control stays on the controller even if the supervision goes down. Support for extended networks depends on suitable network sizing.
Siemens and BACnet openness: real interoperability or sales talk?
PXC controllers carry BTL certification, which guarantees BACnet protocol conformance (BTL website). Integrating LON or KNX on a Desigo network requires additional hardware. BACnet as Desigo's native protocol (in French) is not enough to make an estate truly open. Openness is measured by the number of points actually used, not by the number of protocols listed in the data sheet. However an integrator presents the system, only a count of active points tells the operational truth.
What an Insight to CC migration covers
A migration from Insight to CC involves four critical steps:
- Replacing the supervision layer and rebuilding the graphics
- Requalifying the BACnet points on each PXC controller
- Reprogramming undocumented sequences
- Training operators on the new interface and the workflows that go with it
The cost depends on the number of points to requalify and on the generation of the controllers in place. Rigorous commissioning of a migration avoids losing historical data. A Siemens training centre offers modules dedicated to the maintenance of PXC controllers.
Desigo CC vs Desigo Optic vs non-Siemens BMS: selection criteria for the building owner
Functional scope and openness to third-party networks
| Criterion | Desigo CC | Desigo Optic | Non-Siemens BMS |
|---|---|---|---|
| Functional scope | HVAC + lighting + fire safety + access control on a single interface | Same scope, native Haystack tagging to standardise every point | Varies by vendor - comparable scope with Schneider EcoStruxure, more limited with others |
| Supported protocols | Native BACnet/IP, LON and KNX via gateways | Native BACnet/IP + FIN Framework for semantic tagging | BACnet, Modbus, LON, KNX depending on the vendor - check which drivers are actually maintained |
| Openness to third-party systems | Possible via drivers and gateways - additional engineering cost | Edge2Cloud architecture designed for interoperability | Depends on the number of drivers configured and on whether they are actually maintained |
| Remote access | VPN + dedicated licence | Native Edge2Cloud, browser access | Varies - from proprietary VPN to native cloud depending on the vendor |
| Engineering effort | High - graphics, programs and BACnet points to be rebuilt in a migration | Reduced thanks to Haystack tagging - faster commissioning | Depends on the installed base and on compatibility with existing equipment |
| ESG reporting | Data extraction possible if the meters are reliable | Built-in dashboards, data standardised by Haystack | Reporting functions vary - often manual exports |
| What an independent BMS adviser checks first | How many BACnet points are actually used vs declared in the supervision? | Does Haystack tagging cover all the subsystems or only HVAC? | Are the third-party drivers maintained or frozen since commissioning? |
The functional scope of Desigo CC and Desigo Optic differs on several points. CC covers heating, ventilation, lighting, fire safety and access control. Optic adds Haystack tagging and the native Edge2Cloud architecture. Schneider, the other major generalist, offers a comparable scope with different driver architectures. Software that is multi-discipline on paper can run in a silo if nobody configures the secondary disciplines. Efficiency comes from real configuration, not from a catalogue of functions.
The 5 signs that your Desigo BMS no longer delivers on its promise
Frozen time schedules and persistent overrides
Sign 1: the time schedules have not changed since handover. The heating and ventilation equipment runs two to four hours too long every day. Thermal comfort is maintained by excess run time, not by fine control. Sign 2: overrides set in a hurry six months earlier are still active. Each override bypasses the control and generates invisible overconsumption. Building management (in French) then rests on phantom settings. Perceived comfort masks structural waste that erodes any expected saving.
The French BACS decree and Desigo BMS: what your installation must satisfy
BACS deadlines: who is affected and by what date?
The French BACS decree (in French) (n° 2020-887) sets functional requirements for non-residential commercial buildings. Buildings with a rated output above 290 kW had to comply by 01/01/2025. For buildings between 70 and 290 kW, the deadline was pushed back to 01/01/2030 by decree n° 2025-1343. The decree does not impose any BMS class from NF EN ISO 52120-1: it sets its own functional requirements. The regulation targets how the equipment really operates, not the manufacturer's logo.
What Foobot brings to an estate equipped with Desigo
BMS audit: assessing the real obsolescence of a Siemens estate
Foobot's BMS audit starts with a BACnet read of the PXC controllers in place. We test the control sequences and map the points used vs declared. A PXC can work properly while being declared “end of life” because the spare part is no longer in the catalogue. The audit establishes the facts before any decision. It meets every client's need for a reliable basis to decide between modernisation and replacement. Reducing uncertainty about the condition of the system delivers a usable diagnosis, not a generic report.
From initial audit to AI Control: the 5 key phases
Click on each phase to see the details, deliverables and expected gains
Is the Siemens Desigo CC BMS already installed in your building? Here is how to move from a simple supervisor to continuous energy control, without replacing your existing HVAC equipment.
Mapping of BACnet points, condition of the control loops and savings potential
The technical audit covers the Desigo CC infrastructure in place: exposed BACnet points, firmware versions of the PXC controllers, active control programs and configured time sequences.
- Inventory of the points that can be supervised (typically 200 to 2,000 points per site)
- Detection of setpoint drift and of equipment left in forced manual mode
- Estimate of the energy savings potential (kWh and euros/year)
Non-intrusive integration on the Desigo network with no service interruption
The control layer connects in BACnet/IP read/write directly to the Desigo PXC controllers. No hardware replacement, no HVAC shutdown during installation.
- Dedicated gateway connected to the existing BMS VLAN
- Measurements logged every 5 minutes (temperatures, valve states, power)
- First analyses after just 48 h of collection
Setpoints, sequences and heating curves recalibrated on real data
Based on the logged data collected, the engineers recalibrate the heating curves, the time slots and the load shedding sequences programmed in Desigo.
- Temperature setpoints adjusted to the building's real thermal inertia
- Unnecessary optimal starts removed at weekends and on public holidays
- Less simultaneous heating and cooling (a frequent source of savings: 8 to 15%)
The algorithm anticipates weather and occupancy to control continuously
The AI layer sits on top of Desigo CC: it anticipates thermal needs by combining the D+2 weather forecast, the occupancy calendar and the inertia of the building fabric to calculate the optimal start time.
- AI Optimal Start: HVAC starts as late as possible, not as early as possible (savings on the morning peak)
- AI Control: real-time setpoint adjustment every 15 minutes
- If a simple presence detector is enough, no need for AI: transparency of method
Continuous tracking of real savings with a standardised protocol
Every kWh saved is measured under the IPMVP protocol (International Performance Measurement and Verification Protocol), with degree-day weather adjustment to separate real gains from weather variations.
- Monthly report: savings in kWh, euros and tCO2e avoided
- Comparison of baseline period vs controlled period, corrected for degree days
- Data usable for reporting under the Décret tertiaire (Éco Énergie Tertiaire, France's energy-reduction obligation for commercial buildings)
Is your Siemens Desigo BMS already in place? Find out your savings potential.
Assess the obsolescence of a Siemens estateMeasurement protocol: IPMVP (EVO, 2022). Average gains observed on commercial sites equipped with a class B/A BMS, excluding envelope refurbishment.
FAQ - Siemens Desigo BMS
Is Desigo Insight still supported by Siemens?
Active support for Desigo Insight has ended. Siemens recommends migrating to Desigo CC. Many installations remain in service. The upgrade depends on the budget and on the generation of the PXC controllers in place.
Is Desigo CC supervision or hypervision?
Desigo CC is hypervision. The platform brings together HVAC, lighting, fire safety and access control on a single interface. It controls several disciplines and several sites - well beyond a simple supervisor.
Can you come across the Apogee range in France?
Yes, on multinational sites whose BMS was specified across the Atlantic. Apogee is Siemens' North American range. The protocol remains BACnet-compatible but the documentation differs from the European Desigo range.
What is the difference between Desigo PXC and Synco?
The Desigo PXC is a programmable controller for complex buildings (hospitals, head offices). Synco is a compact controller for small standardised sites. The choice depends on the number of items of equipment to control.
How much does it cost to migrate from Desigo Insight to Desigo CC?
The cost depends on the number of points to requalify and on the generation of the PXC controllers. Each migration is priced after an audit. Commissioning includes rebuilding the graphics and training the operators.
Can Desigo CC integrate with third-party systems?
Yes, natively via BACnet. Integrating LON, KNX or Modbus protocols requires additional gateways. The real degree of openness depends on the number of drivers maintained in operation.
How does Desigo Optic simplify integration?
Haystack tagging standardises the tags of every BMS point. A new integrator understands the logic without going back through all the documentation. Using this standard reduces the engineering effort from the integration phase onwards.
How does Desigo CC manage energy?
Via the built-in PowerManager module. It centralises the monitoring of electricity consumption and the management of power peaks. The energy consumed by each zone becomes traceable from the supervision.
How does Desigo CC secure information systems?
Through user role management, BACnet/SC encryption and IEC 62443 compliance. Security was strengthened with version V9 - systematic authentication and logging.
Do you need a BMS like Desigo to comply with the French BACS decree?
The French BACS decree imposes building management functions, not a manufacturer. A building equipped with a non-Siemens BMS that meets the functional requirements is enough. Automation is verified function by function.