How Far Should You Push Performance? Rethinking High-Performance Building with Andy Marlow of Envirotecture

Andy Marlow's definition of efficiency in passive house and airtightness will annoy some people: it's doing the bare minimum required to clear the hurdle, which he says is much the same as being really bloody lazy. Andy is a director at Envirotecture, a long-time passive house advocate and former Australian Passive House Association board member — and he thinks the industry's obsession with beating its own numbers is costing builders money for no measurable gain.

The core of the conversation is where the point of diminishing returns actually sits for high performance. Once a building is genuinely airtight, the model becomes predictable (you can't model a sieve) and that predictability is what lets you cut back everything else. Andy walks through the UK apartment work presented at the Passive House Conference where parts of the building are deliberately built worse than code because the form factor absorbs it, the concrete footings nobody needs to perfect, and the one thing you can never compromise on: condensation risk.

Brian makes the same case from the other direction — that a decade of chasing certified air-tightness is what teaches you how much performance you can buy for far less. They get into the airtightness arms race between builders, the bloke who hit 0.06 and probably wasted his weekends doing it, achieving 2 ACH cheaply through the plasterboard line, and whether a tiered certification pathway would drag the volume market across the line. Andy also explains the relaunch of Passive House Design & Construct as pre-designed-only homes — the same logic applied to design fees.

EPISODE HIGHLIGHTS

• An educated way to cut corners.
• The airtightness arms race — 0.6 versus 0.5 versus the 0.06 warehouse, and where the ego takes over from the engineering
• Condensation risk as the one thing you don't get to compromise, and Andy's caution on loosening airtightness
• Low Energy Building as the sensible tier down, and why a 300mm-plus wall isn't always financially sane
• Health, comfort and longevity as the real product — "no one cares about energy efficiency"
• Applying the same logic to design: the relaunch of Passive House Design & Construct as pre-designed homes you can't modify

LEARN MORE
Envirotecture: https://www.envirotecture.com.au/
Passive House Design & Construct: https://passivhausdc.com.au/
Sustainable Builders Alliance (SBA): https://www.thesba.com.au

BROUGHT TO YOU BY
Sustainable Builders Alliance (SBA): https://www.thesba.com.au