The Hidden Danger in Every Old House

“If you can’t hit 0.6 ACH on a brand-new build, you probably shouldn’t be building.”

Let’s stop tip-toeing around the reality of the Australian housing market. We are throwing up volume-built boxes and high-density apartments that are practically end-of-life before they’ve even seen their first winter. We sat down with Linden Thorley, architect, Passive House designer, and chair of the Australian Passive House Association Retrofit Committee.

We take a look into why retrofitting the existing 9.5 million homes in Australia is the single biggest business opportunity for trades over the next decade. Linden walks us through the differences between a cosmetic renovation and a high-performance retrofit, detailing how his team utilises the PHPP (Passive House Planning Package) to model data and manage moisture, insulation, and ventilation risks case-by-case.

We don't hold back on the real pain points of the industry either. We talk about the skyrocketing costs of business insurance, why Australian labour rates are fundamentally shifting project costs, and how to structure building contracts using provisional sums for airtightness so builders aren't crushed by unexpected site variations.

Linden also breaks down his frustrations with legacy bank valuations that prioritise bloated 300-square-meter floor plans over highly efficient, smaller family homes.

Finally, we hit the political wall: how heritage advisors and council planners are actively preventing energy efficiency upgrades, and the clever, practical drawing tricks

CHAPTER MARKERS

00:00 – Introduction

02:08 – The Passive House Association Retrofit Committee & Playbook

04:12 – Finding the Ideal Market: How Long Does the Shift Take?

05:45 – Passive House as a Design-Agnostic Calculation Tool

07:11 – Can a House Be Great If It Doesn’t Reach Certified EnerPHit?