Building physicists Veronika Heidegger and Ad van der Aa are the Jaap Oosterhoff Visiting Professors at TU Delft for the autumn of 2026. With their shared expertise, the specialists from ABT want to show students and researchers how building physics can contribute to the major challenges of our time, from climate change and health to sustainability and digitalization. Their central message: building physics is not primarily about complying with rules and labels, but about understanding, predicting, and realizing the actual performance of buildings.
Building physics investigates how factors such as heat, moisture, sound, light, air, and fire safety influence the performance of buildings, and thereby also comfort, health, safety, and sustainability. In doing so, the field helps translate design choices into actual building performance. Standards play an important role in this: they make quality verifiable and provide guidance to designers, builders, and clients. At the same time, Veronika Heidegger and Ad van der Aa warn that complying with standards is not the same as understanding how a building functions in practice. Ad: “Standards have helped enormously to improve the quality of buildings. But a building can meet all formal requirements and still fail to meet expectations.”
Reality is more complex than a model
Engineers use models to design buildings. These models are indispensable, but always a simplification of reality. Heat, moisture, ventilation, daylight, and acoustics constantly influence each other. Moreover, buildings change over time, are used by people, and have to deal with a changing climate. As a result, uncertainty and robustness play an increasingly important role. The focus is not on one exact answer, but on insight into how buildings behave under different conditions.
Veronika: “The question is not only how accurate a calculation is, but also how robust a design remains when conditions change. It is precisely then that you see how well a building actually performs.”
Measuring, understanding, and learning from reality
According to Veronika and Ad, no new building physics needs to be invented for this. Much of what is becoming important again today actually belongs to the original core of the profession: observing, measuring, and understanding what is really happening. Based on that knowledge, models are developed, predictions are made, and solutions are designed, after which it is tested whether those predictions correspond with reality.
Ad: “We need to return to the core of the profession. Understanding and comprehending which physical processes are at play, measuring what is actually happening, and testing our models and assumptions against that.”
Modern technology makes this possible better than ever. Sensors, monitoring, and data analysis offer new opportunities to learn from realized buildings. This creates a continuous learning cycle of measuring, understanding, modeling, predicting, realizing, and learning again.
AI requires engineers who understand why
Veronika: “AI can accelerate routine work, creating more room for in-depth analyses and optimizing building performance.” But AI does not change the foundation of the profession. Precisely because calculations and analyses are increasingly being automated, engineers must continue to understand which physical processes are relevant, what assumptions underlie models, and whether the outcomes are logical. That also demands something from education: future engineers must not only learn to apply standards or calculation programs, but above all understand what lies behind the results and how they are arrived at.
Ad: “AI can support the engineer’s work, but not take over responsibility. Engineers must remain in control themselves and know when they should not trust a computer answer.”
Building physics for the challenges of tomorrow
With this, the discussion on building physics touches upon a broader task. The field calls for renewed depth: not the blind application of standards, models, and calculation programs, but a continued understanding of the physical reality behind them. This depth is necessary now that buildings must perform better under pressure from climate change, health, comfort, energy consumption, and the need for robust quality over time.
The challenge is to bring craftsmanship and societal challenges closer together. Building physics can only provide a convincing answer to the questions of tomorrow when engineers understand what they are doing: which assumptions are uncertain, what models and AI do or do not show, and how results relate to reality. This calls for measuring, testing, and maintaining critical thinking, but also for taking responsibility for the results delivered. This is precisely where the challenge lies for students and the program: engineers do not all possess these qualities and calculate solutions, but can vouch for the performance of buildings in practice.
Oosterhoff Program
The visit by Ad van der Aa and Veronika Heidegger is part of the Jaap Oosterhoff Visiting Professor Program, a multi-year initiative that invites leading experts to share their knowledge and vision with students and researchers. The program focuses on current and future challenges in the built environment, including digitalization, circular construction, urban transformation, and sustainable technologies. Through guest lectures, workshops, and a public lecture within the BK Talks series, the visiting professors bring new perspectives to education and research at the Faculty of Architecture.
The Jaap Oosterhoff Visiting Professor Program is an initiative of the Department of Architecture (Architecture Engineering & Technology) at TU Delft, in collaboration with Oosterhoff and the innovation think tank Quake. The chair is led by Ulrich Knaack (TU Delft) and Jaap Wiedenhoff (Quake). Together, they ensure an inspiring interaction between the academic world and practice. The program is named after Jaap Oosterhoff, who founded his own engineering firm in Arnhem in 1953 – the beginning of what would later become ABT and Oosterhoff. His vision was progressive: to build a society in which people live in harmony with their environment. This idea still forms the core of the program.
Image: TU Delft – Bart Haagsma
