Each month, PTE's Knowledge Hub team will explore the complexities and technical challenges British project architects face every day.

Let’s be honest: the UK construction industry has a bad habit of designing buildings as if they exist in a vacuum. Regulations are met on paper, SAP scores are massaged into compliance, and everyone pats themselves on the back when the last snag is signed off. And then? People move in. And that’s when we find out if what we built works as intended - or, more often than not, that it doesn’t.

The performance gap is the industry’s dirty little secret, and it’s why Post-Occupancy Evaluation (POE) and Building Performance Evaluation (BPE) aren’t just nice-to-haves; they’re fundamental to designing and delivering homes that actually perform.

At PTE we have been working with the Good Homes Alliance and the Building Performance Network since 2011, pushing for better standards across the sector. We’ve also helped shape BS40101, the British Standard for Building Performance Evaluation. The goal? To end the reliance on inconsistent data and ensure that when we claim a building is energy efficient, comfortable, and well-ventilated, it actually is. That’s why we’ve embedded BPE into recent projects like Peasecroft and Marleigh - because if we’re not measuring, we’re just guessing.

If you want to see what happens when buildings are designed properly from the start, look at Passivhaus. No other standard delivers such predictability in energy use, comfort, and air quality. And the proof? POE after POE confirms that Passivhaus homes perform exactly as they’re meant to. This might sound unremarkable - until you remember that most homes built to standard UK regulations don’t. The performance gap isn’t just a few percentage points here and there; we’re talking about homes that use twice as much energy as predicted. That’s not just inefficiency; it’s failure.

Passivhaus avoids this by demanding rigour at every stage. The Passivhaus Planning Package (PHPP) isn’t just a model - it’s an exacting process that ensures the numbers you plug in translate to real-world performance. That means airtightness is actually airtight. That means ventilation strategies actually work. And it means energy bills are what was promised. But most importantly, the homes are comfortable - something most UK new-builds fail to deliver in summer and winter alike.

There’s a reason Passivhaus homes perform so well: they undergo rigorous third-party assessment and certification. Every layer of insulation, every junction, every service penetration is checked and verified. The rest of the industry, meanwhile, operates on wishful thinking. And that’s why UK homes remain leaky, uncomfortable, and prone to overheating. BPE is the only way to change this, exposing poor performance and closing the loop between design, construction, and lived experience. At PTE, our Cambridge Passivhaus projects are proving that we can build better, and we’ve joined the Passivhaus Trust to push these principles across all our work.

If you want to hear more, I’ll be at Futurebuild, discussing why BPE isn’t optional - it’s the key to making sure the homes we design actually work. Because if we’re not doing that, what’s the point?