Published on August 26, 2026
The Future Under Construction: Virtual Reality Meets the Energy Transition in Existing Buildings
The construction industry faces major challenges. According to the Federal Association for Energy-Efficient Building Envelopes (BuVEG), the renovation rate for Germany’s existing building stock stood at just 0.67 percent in 2025. To meet climate targets in the building sector, a rate of around two percent would be necessary. Especially when it comes to existing buildings, there is often a lack of reliable data on which to base investment decisions. Every decision is costly, complex, and often amounts to gazing into a crystal ball. The central question is therefore: How can renovations be managed in a cost-effective, well-informed manner while maximizing their climate impact?
Hybrenergy: The Digital Twin for Energy Consulting
The research project “Hybrenergy,” funded by the Federal Ministry for Economic Affairs and Energy, offers a potential solution. It combines building and operational data into a hybrid digital twin that makes energy-related relationships visible and quantifiable. Simulation, optimization of building services (TGA), and virtual reality (VR) are integrated into a single application. The goal is to analyze energy consumption at the simulated building and to prioritize investment decisions based on data. Partners from research and industry are involved: in addition to the Karlsruhe Institute of Technology (KIT), the Research Center for Information Technology (FZI), RWTH Aachen University, and consortium leader Schneider Electric GmbH are active in the project. Also participating are the companies Lumoview Building Analytics GmbH, Actimage GmbH, and Archis Architekten + Ingenieure GmbH. The goal: to measurably reduce CO2 emissions in buildings – both in existing structures and in new ones.
For Schneider Electric, the existing building stock was of particular interest. While new buildings are increasingly planned and documented digitally today, existing industrial buildings often lack reliable information about their technical equipment, usage, or energy-related aspects. The company therefore made one of its own production sites available as a demonstration site. “There is enormous potential, especially in the existing building stock. We were particularly interested in how existing buildings can be digitally mapped–not only geometrically, but also in terms of their technical equipment and usage,” explains Ingo Gitschier, a graduate engineer (FH) in building services engineering, project consortium leader, and responsible for digital maintenance within building automation projects at Schneider Electric. In addition to gaining insights, the company was also interested in how existing solutions and products could be integrated with such digital twins in the future.
A virtual look behind the facade
“But people are always at the center,” emphasizes Dr.-Ing. Polina Häfner. As an expert in virtual engineering and rendering at KIT’s Institute for Information Management in Engineering (IMI), she played a key role in developing the hybrid twin and has been involved in the project from the very beginning. In addition to technology and costs, greater emphasis is being placed on comfort and quality of life for the people in the building in question. Visualizing renovation measures helps to understand complex interrelationships, compare structural changes, and coordinate decisions efficiently. Measures become tangible and can be compared within the system by calculating investment costs, energy consumption, CO₂ emission savings, and other parameters – even before the first euro is invested. This makes renovation decisions faster, more transparent, and more robust. The project is taking place at a Schneider Electric production facility from the 1960s consisting of eleven building units. The site in Neuenstadt am Kocher is typical of industrial areas that have grown over decades and feature a high degree of technical diversity – making it an ideal testing ground for Hybrenergy to investigate energy optimization during ongoing operations.
From a dataset to a tangible structure
The building complex was first surveyed using a drone. Photographs were taken from a wide variety of angles; specialized software analyzed the images and generated point clouds, which were then combined into what is known as a photogrammetric model–a 3D visualization, Häfner explains. In addition, laser-based scanning technology from Lumoview, supported by AI, provided precise 3D representations of the building’s interior. Both datasets form the basis for the digital twin developed at the IMI. The digital model encompasses not only the building’s geometry but also extensive metadata on components, materials, and technical properties. This information can be used directly for thermal simulations. This allows the building’s behavior under various operating conditions to be simulated realistically. To collect important real-time data during operation, Schneider Electric additionally installed and analyzed nearly 1,100 sensors in various areas of the building. These sensors provide information on air quality, room temperature, humidity, lighting systems, blinds, and solar radiation – factors that significantly influence a building’s energy-efficient operation.
That’s when Häfner, a computer scientist and virtual reality engineer, came into the picture: She took charge of integrating and visualizing the data within the digital model of the industrial complex. Given the large, heterogeneous volume of data, this was a challenging task. “But the algorithm gets better with every building and every production hall,” says Häfner. The immersive demonstrator is based on “PolyVR,” the virtual reality system environment developed at IMI. It is not designed as a simple 3D viewer, but rather as a process chain: from the digitally captured inventory, through the data-enriched current state, to the simulation and evaluation of specific optimization approaches. Sensors, conditions, and simulations can be selected via a dashboard. Analog data and experiential knowledge of building services have also been integrated and standardized. This creates a digital twin of the company’s site that bridges reality and simulation.
When Simulation Becomes Strategy
Häfner proudly presents the digital twin, which allows for a virtual tour of the industrial complex – through the production areas and employees’ offices. “You can even see how often the lights were turned on or the restrooms were used,” Häfner says with a smile. Data on current solar radiation on the window surfaces and the temperature there are also available. But the real strength lies not in virtualization alone, but in using the digital twin for energy simulations. To this end, the project partners at RWTH Aachen University are starting by calibrating the simulation parameters in the model. The simulation is currently based on methodological example scenarios. As the project progresses, these will be further developed using calibrated real-world data to provide a reliable basis for decision-making: What happens when solar panels are installed on the roof, walls are insulated, a window is replaced, or a heat pump is installed? Could the waste heat from a drying machine in the production area be used to heat the nearby office? And how would this affect the building's energy consumption and carbon footprint?
When Data Shows Where Energy Is Lost
While Schneider Electric handled data collection, the participating teams from RWTH Aachen University used this information to optimize the energy simulations in the digital twin. Proven methods from mechanical engineering and automation are being applied to the building. The goal is to create a simulation that accurately reflects the building’s actual performance, thereby providing a solid foundation for developing and prioritizing renovation options. Property owners and investors can thus evaluate the energy performance of their properties and prioritize measures where they will have the greatest impact. Virtual reality is not an end in itself, but rather a decision-support tool. Schneider Electric sees this as the application’s greatest practical benefit. Initial analyses of the demonstrator showed, for example, that individual areas of a building are used very differently. While some areas are heavily trafficked, others remain virtually unused at times. This opens up new possibilities for space planning and energy use. At the same time, investment costs can be weighed against the expected savings. “Ultimately, even for industrial companies, it comes down to whether a measure is cost-effective,” says Gitschier. “If we can realistically simulate financial expenditures and the underlying energy savings, modernization measures can be justified on a much more solid basis.”
Between Potential and Practice: When Good Models Encounter Missing Data
However, the project has not only revealed potential but also highlighted limitations. From Schneider Electric’s perspective, the biggest challenge right now is not the simulation itself, but rather obtaining the necessary data. Much of the information regarding building usage, technical equipment, or comfort requirements is not centrally available in the existing data and often has to be collected manually. “The output is good. The process leading up to it still has room for improvement,” Gitschier summarizes. For specific customer projects, the effort involved is still too high in some cases. He sees potential for further research here: “In the future, AI-supported methods, digital building documentation, or smart sensors could help to further automate data collection and model generation, thereby making the process more cost-effective.”
The Path to a Scalable Energy Transition
“Thanks to the virtual reality application, an investor can sit in New York and still comfortably walk through the building, compare scenarios, and better assess potential measures. Building services engineers can also use the digital twin to prepare for operations and maintenance work remotely. This reduces the need for coordination and can make on-site operations more efficient. Everything can be assessed remotely.” This means less coordination effort, better preparation, and more efficient on-site implementation. The long-term vision extends beyond individual locations. For Schneider Electric, the hybrid twin could be used in the future not only within its own building portfolio but also to support energy consultants, facility management providers, and building operators in planning and evaluating measures. Project results are already being used to explore opportunities for integrating these functions into existing software solutions and facility management systems. Looking ahead, these approaches can be scaled up to encompass entire neighborhoods and districts, integrated energy systems, and their energy optimization. Combined with artificial intelligence (AI), automated renovation proposals could also be developed in the future. The NaiS project (Sustainable Intelligent Renovation Measures), coordinated by KIT, is already demonstrating how AI can analyze complex building data and accelerate data-driven renovation planning.
Greater Transparency in the Building Stock
Hybrenergy demonstrates how the existing building stock can transition from operating blindly to making decisions based on data. The hybrid digital twin creates transparency in day-to-day building operations, makes the effects of renovation measures traceable, and enables investments to be prioritized based on reliable data. In this way, the project provides a practical approach to specifically reducing energy consumption and CO₂ emissions.
The future of building renovation is virtual
For Schneider Electric, the project also demonstrated the potential of combining building data, simulation, and digital visualization – and where further development is needed for broad market adoption. “We’ve shown that the approach works. The next challenge is to automate data collection and model generation much more extensively,” says Ingo Gitschier of Schneider Electric. “If we succeed in doing that, there is enormous potential for the energy optimization of existing buildings.” For Häfner, this is precisely a key insight from the project for applied research: “The beauty of applied projects is that we’re solving a concrete problem. We’ve identified the ‘pain points’ and were able to develop targeted solutions for them,” she summarizes. The digital twin and immersive virtual reality thus exemplify a new generation of data-driven tools in building management. They lay the foundation for more informed investment decisions and more efficient renovation strategies – and demonstrate how environmental and economic goals can be aligned in the existing building stock.
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