Balancing sustainability and budget: navigating the Passivhaus standard in public sector projects

In conversation with Emma Osmundsen — also Passivhaus pioneer and Chair of the Passivhaus Trust — we explored the growing momentum behind the Passivhaus standard, addressed some common misconceptions, and discussed that sustainability and cost-efficiency are not mutually exclusive.

There is now over 15 years of proven data and positive user experiences to support the Passivhaus standard in the UK. With changing climate conditions and evolving regulations, it’s clear that robust, future-proofed approaches like this will only continue to gain momentum.

So why isn’t everyone adopting it? While cost is often cited, Emma and I agreed that the real issue is often a fear of the unfamiliar.

Emma, who has delivered multiple Passivhaus projects including the UK’s first Passivhaus leisure centre, explained that with experienced teams and robust quality assurance, meeting the standard isn’t about reinventing the wheel. Her Victoria sponge analogy really resonated: “The ingredients for a Passivhaus home aren’t much different to a standard home - the key is following the order of the recipe.” With early engagement and intelligent design, the cost premium can be minimal. As the industry gains more experience, what once felt like a risk can quickly become business as usual.

Another challenge lies in who benefits from the long-term savings. While Passivhaus has a capital cost uplift, it’s typically outweighed over time by reduced operational costs. But in the public sector, where capital and operational budgets are often managed separately, this long-term value can be hard to unlock.

That’s slowly starting to change. One house builder recently committed to delivering all its London developments to Passivhaus standards, and customer interest is growing across schools, leisure centres and other sectors. The key is translating technical performance into what matters to people: lower energy bills, improved comfort and better health.

I was keen to highlight that while a Passivhaus certified building provides performance assurance, loosely applying Passivhaus principles won’t get you the same result. Taking a “pick and mix” approach to Passivhaus significantly lessens the overall performance of the building, and in the worst-case scenario can cause issues like condensation or mould. Using Emma’s analogy of a Victoria sponge — what would happen if we left out the eggs or didn’t put in enough flour?

Without the rigour of certification, it’s easy to end up with a building that underperforms compared to original benchmarks and energy models. This performance gap often goes unnoticed simply because the extensive testing required for certification hasn’t been done. Yet the cost of certification is minimal compared to the assurance it offers — it gives building owners confidence that they’re receiving the energy efficient building they set out to achieve.

Emma stressed the importance of thinking about buildings as investment assets, which naturally leads to more sophisticated, future-proofed decision-making around where, how, and why we invest. As she put it, “Everyone wins with Passivhaus...from an investment perspective, the investors benefit...our residents benefit, society benefits. Passivhaus is not just an energy standard…it’s actually a hygiene standard.”

That point is especially relevant now. Passivhaus was founded on the principle of comfort, not just energy. It's about improving wellbeing by addressing overheating, condensation and poor air quality.

With new legislation targeting mould and damp in homes, building to high hygiene standards has never mattered more. By addressing underlying causes like condensation and poor insulation, we can reduce health risks and ease pressure on the NHS. As Emma put it, “we can’t afford not to do Passivhaus.”

We also discussed how certainty and incentivisation could help make Passivhaus a default choice. I suggested that stipulating certification in contracts could bring clarity and confidence – something not yet common but increasingly relevant.

Emma pointed to the strong uptake of Passivhaus in Wales and Scotland, crediting much of that success to government funding being linked directly to building performance outcomes. When projects must demonstrate how they reduce whole-life costs, improve health outcomes, and enhance climate resilience, Passivhaus becomes an obvious solution.

We were both optimistic that Passivhaus is no longer a niche concept, but a serious strategy for sustainable construction. Our role now is to keep sharing, collaborating and showing that high-performance buildings aren’t just possible – they’re essential.

Want to learn more?

If you’re looking to understand how these insights could apply to your organisation or simply want to explore the topic further, get in touch with Lorna Taverner. She’d be pleased to talk through your challenges and how we can help.

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Find out more about Willmott Dixon at UKREiiF 2025 and further event insights: www.willmottdixon.co.uk/ukreiif