Retrofit in building automation: How to make existing buildings fit for the future

In times of energy shortages, sustainability targets and legal requirements Pressure The focus on the building sector is increasingly shifting to one question: How can existing buildings be brought up to a sustainable standard - without building new ones? The answer to this is increasingly: Retrofit.


Particularly in the field of technical building automation (TGA) - i.e. the technical control of heating, ventilation, air conditioning, lighting and security - a targeted retrofit can not only drastically reduce energy consumption, but also create the basis for digital services, remote maintenance and efficient operational management. But what does retrofit actually mean? And why is there now no alternative for many properties?

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Retrofit in building automation - advantages at a glance

  • Bis zu 30 % Energieeinsparung

    durch moderne Automationssysteme (Quelle: Fraunhofer ISE)

  • Modular nachrüstbar

    Bestehende Systeme lassen sich ohne Komplettaustausch erweitern

  • Pflicht zur Gebäudeautomation ab 290 kW Heiz-/Kühlleistung

    laut aktueller EU-Richtlinie EPBD

  • Mehr Transparenz

    Retrofit schafft die Grundlage für Energiemonitoring, ESG-Reporting und KI-gestützte Optimierung

  • Schneller ROI

    Investitionen in Automations-Retrofit amortisieren sich oft innerhalb von 3–5 Jahren

  • 70 % der Nichtwohngebäude

    in Europa sind älter als 20 Jahre – enormes Modernisierungspotenzial

  • Zukunftssicherheit

    Veraltete Komponenten werden ersetzt, bevor Wartung oder Ersatzteile unmöglich werden

Retrofit: More than just "modernizing"

The term retrofit describes the Technical retrofitting or modernization existing plantsmostly with the aim of Improve efficiency, functionality or connectivity. In contrast to a complete refurbishment, a retrofit does not involve the demolition or replacement of the entire technology, but rather the targeted integration of new components into existing systems.
In building automation, for example, this means:

  • Old control systems are being replaced by new, communication-capable systems.
  • Field devices that are no longer available are replaced by modern sensors.
  • Systems without a data connection are integrated into higher-level control systems (BMS).
  • Analogue signals are digitized so that energy consumption becomes transparent.

The goal: A Smart operationwithout having to completely redesign the existing building technology.

Contents

Typical areas of application for retrofitting Vorteile für Gebäudenutzer The challenges of retrofitting Transparency, modularity and communication thanks to retrofit Conclusion Retrofit

Why retrofitting is now more urgent than ever

Numerous buildings in Germany and Europe - from administrative buildings to industrial halls - have automation systems that are more than 20 years old. Many of these systems still work reliably, but do not meet the current state of the art or the requirements for energy efficiency, transparency and networking.

Particularly in view of current challenges, the retrofit approach makes economic and ecological sense:

  • Energy efficiency: A retrofit makes it possible to optimize building automation systems in accordance with EnEV, GEG or DIN EN ISO 50001 - in particular through better measurement, control and evaluation.
  • Sustainability and ESG: Sustainability criteria such as the carbon footprint and ESG (Environmental Social Governance) requirements are increasingly demanding detailed consumption data and optimization measures - a retrofit creates the technical basis for this.
  • Availability & service life: Many older systems are no longer maintainable or are no longer supported by the manufacturer. Spare parts are missing. Retrofitting creates planning security.
  • Digitization: If you want to implement digital services such as remote access, predictive maintenance or energy monitoring, you need a modern automation structure - and therefore often a retrofit.
  • Regulatory requirements: The revised EU Energy Performance of Buildings Directive (EPBD) requires, among other things, the use of automation technology in non-residential buildings, provided this is technically and economically feasible. The aim is to automatically record, analyze and optimize energy consumption. A retrofit is the key lever for meeting these requirements in existing buildings too.

The typical areas of application for retrofitting in building automation

A retrofit is usually Not a one-off interventionbut a Individual concepttailored to the respective building structure and automation architecture. The spectrum ranges from simple partial modernizations to comprehensive system conversions. The key often lies in the interaction between BMS and MEP: a retrofit modernizes the control of HVAC systems, boiler systems or lighting systems - i.e. classic MEP systems - and integrates them into a holistic building management system via standardized interfaces.
Examples from practice:

  • An existing BMS is extended or replaced by an up-to-date system that uses modern protocols such as Modbus, Wireless Modbus, BACnet or KNX supported.
  • Individual control systems (e.g. for HVAC units or refrigeration systems) are equipped with new, interoperable controllers.
  • Data collection is supplemented by modern sensor technology at room level - for example for CO₂ measurement, presence detection or humidity control.
  • Existing infrastructure is transferred to a central energy monitoring system, often via IoT gateways or a cloud connection.

It is importantRetrofit does not mean blindly replacing old systems with new ones, but rather using the potential of existing technology intelligently and only supplementing it in a targeted manner.

Vorteile für Gebäudenutzer

Komfort & Wohlbefinden

Retrofitting mit moderner Gebäudeautomation sorgt für konstant angenehme Raumtemperaturen, unabhängig von Wetter oder Tageszeit. Intelligente Sensorik verbessert die Luftqualität durch automatische CO₂-Überwachung und bedarfsgerechte Lüftung. Ergänzend schafft intelligente Beleuchtung, die sich an Tageslicht und Nutzung anpasst, eine angenehme und produktive Umgebung.

Höhere Sicherheit & Gesundheit

Durch Retrofitting profitieren Gebäudenutzer von moderner Zutrittskontrolle und integrierten Brand- und Rauchmeldern. Automatische Alarmmeldungen bei Wasser-, Brand- oder Gaslecks erhöhen die Sicherheit und ermöglichen eine schnelle Reaktion im Notfall – für ein beruhigendes Gefühl im Alltag.

Flexibilität

Mit Gebäudeautomation lassen sich Heizung, Licht und Lüftung komfortabel per App oder Sprachassistent steuern. Räume werden bedarfsgerecht genutzt, was den Komfort erhöht und gleichzeitig Energie spart.

Umwelt & Lebensqualität

Retrofitting ermöglicht eine automatisierte Optimierung des Energieverbrauchs und reduziert den CO₂-Ausstoß spürbar. Das Ergebnis ist eine höhere Lebens- und Arbeitsqualität durch eine angenehme, gesunde und nachhaltige Raumumgebung.

Challenges: Retrofit is not plug & play

As sensible as retrofitting is, it does present certain hurdles when it comes to implementation. Old control systems are often proprietary, the documentation is incomplete and many systems were installed historically. This makes retrofit planning more complex than for new buildings.

Important questions that need to be clarified in the course of the project:

  • Which interfaces are available and how can they be used?
  • How interoperable is the new technology with existing systems?
  • Is successive modernization possible - e.g. floor by floor or by trade?
  • What data should be recorded, transmitted and analyzed?
  • What is the long-term IT and OT strategy for the building?

Here is Experience in demand - both on the part of the system integrators and the decision-makers. A retrofit without sound analysis and forward-looking planning can quickly become expensive or produce technical bottlenecks.

The key to success: transparency, modularity and communication

A well thought-out retrofit follows a modular, future-proof approach:

  • TransparencyData must be easily available and analyzable - ideally in real time.
  • ModularityNew components should be able to be added or replaced at any time without jeopardizing the overall system.
  • CommunicationOpen protocols and standardized interfaces are crucial to ensure the future viability of automation.

Especially in the context of IoT and cloud-based systems, it is clear that a retrofit can be the gateway to the world of smart buildings - but only if interoperability is consistently taken into account.

Customized retrofit components from S+S

If, as part of a retrofit project, you are looking for modern, retrofittable sensor technology for Temperature, Humidity, Pressure, Air quality, CO₂ or Brightness/ movement are: We offer a wide range of solution-oriented components that can be seamlessly integrated into existing systems - whether wired or wireless with Wireless Modbus.

  • High measuring accuracy for efficient and stable control
  • Digital communication via Modbus RTU and Wireless Modbus for fast, cost-saving retrofitting
  • Modern room operating units and room controllers such as Rymaskon
  • Flexible field devices with scalable measuring ranges, adjustable offset and optional display
  • Ready for immediate use thanks to pre-calibrated delivery
  • Integrated fault detection (e.g. sensor break, sensor short circuit)
  • Suitable designs for every measuring point: room, duct, contact or pendulum

Conclusion: Retrofit is an investment in the future - not in the past

Retrofitting in building automation is Not a short-term emergency solutionbut a strategic step towards future-proofing existing properties. Investing in modern control, measurement and communication at an early stage lowers operating costs in the long term, reduces CO₂ emissions and increases the value of your property.

Now is the right time for operators, planners and building owners to review their own portfolio: Which buildings could be operated more efficiently, smarter and more sustainably through retrofitting?

Discover and compare suitable sensors now

FAQ

What role does sensor technology play in retrofitting?

Sensor technology is the basis of all automation. Precise, reliable measured values determine how efficiently control, monitoring and optimization can be carried out - especially in existing buildings. This data makes it possible to control energy consumption in real time and avoid inefficient operating times. In this way, intelligent sensor technology helps to cut energy costs and reduce CO2 emissions.

When is a retrofit particularly worthwhile?

A retrofit makes sense if the existing system is still technically functional, but the measuring accuracy, transparency or communication no longer meet today's standards - for example, in the event of rising energy costs or new regulatory requirements. In addition, a retrofit project can usually be implemented much more quickly than a new build.

Is a retrofit also possible while the building is in operation?

Yes, radio-based solutions and pre-calibrated devices in particular enable quick and efficient retrofitting with minimal intervention. This significantly reduces downtimes and has minimal impact on ongoing operations. These flexible retrofit solutions offer a cost-effective way to modernize existing systems without significantly disrupting operations.

Do all field devices have to be replaced during a retrofit?

No - it is often sufficient to replace or add individual sensors, controllers or interfaces in order to achieve significant efficiency gains and optimize energy consumption. This customized retrofit offers a cost-effective alternative to completely new systems and ensures a sustainable improvement in operating processes.

Supported S+S Regeltechnik Targeted retrofit projects?

Yes, S+S offers a comprehensive portfolio of retrofittable field devices, room controllers and communication solutions that have been specially developed for retrofit applications in HVAC building automation. Our solutions enable efficient modernization of existing systems and increase the energy efficiency and operational performance of buildings through innovative retrofit technologies.