Becks moves HVAC design from assumptions to data-driven decisions with Hysopt

At consultancy firm Becks, the focus lies on sustainable buildings and complex HVAC challenges, often within the leisure sector. With more than thirty years of experience in building services engineering, Gert Moonen, Commissioner Sustainable Energy at Becks, has developed a clear vision of how systems should be designed.

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That vision often clashes with traditional design approaches. As he explains, buildings are still too often designed for extreme conditions — “minus ten or plus thirty” — while reality lies somewhere in between, with continuously varying occupancy and loads.

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It was precisely this gap between theory and reality that led Becks to look for a different way of working — less static, and more aligned with how buildings actually perform over time.

Previously, the design process relied heavily on experience, supported by calculations in tools such as Vabi and Excel. As Gert explains, projects often started by “simply making a system choice based on experience and figures.”

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While this approach worked in many cases, it remained limited. The calculations were largely static and only provided a snapshot of system behaviour.

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With Hysopt, that fundamentally changes. Instead of relying on fixed assumptions, they can now analyse how a system behaves over time. Simulation plays a central role in this. As Gert puts it, these simulations are “incredibly powerful” and have become the most important part of his workflow.

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As a result, decisions are no longer based solely on experience, but on measurable insights.

This dynamic approach also puts certain design choices into a new perspective. For example, Becks has gained deeper insight into the behaviour of changeover systems.

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Where Gert already had doubts before, he now clearly sees why these systems often cause issues in practice. “Switching between heating and cooling is almost impossible to manage properly,” he explains — something that is confirmed through both simulation and real-world experience.

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At the same time, Hysopt allows Becks to better substantiate design decisions towards clients. Where rules of thumb were previously used — for example regarding the share of a heat pump — they can now quantify the exact impact.

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Instead of saying a system covers “around 70 or 80%” of the demand, they can now demonstrate that it is, for instance, exactly 74% on an annual basis.

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This shift from assumptions to quantified results significantly strengthens both credibility and decision-making.

One of the biggest advantages today is the ability to quickly gain insight into energy use and capacity profiles, especially in a context where grid capacity is increasingly limited.

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Gert uses Hysopt to analyse how much power a system actually requires throughout the year and how often peak demands occur. This enables more targeted decisions, for example when sizing heat pumps.

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As he points out, these are often major investments — ranging from hundreds of thousands to millions of euros. With better insight, this sizing can be significantly optimised.

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This approach also leads to different design decisions, such as selecting smaller heat pumps or correctly sizing buffer tanks. Insights that were previously based on intuition can now be quantified and supported with data.

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What changes most, however, is how these insights are communicated to clients. Where decisions were previously based on experience and assumptions, Becks can now present clear, data-backed results. As Gert explains, “In the past, it was often something clients had to take your word for, whereas now we can demonstrate with calculations what a system actually does.”

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That shift makes a real difference in client conversations. It not only improves understanding, but also builds trust in the proposed solutions. Whether it’s system sizing or the impact of a design choice, the story becomes concrete, measurable, and convincing.