We Talked Ourselves Out of a $550,000 Job. Then We Built a Certified Passive House Instead.

Most builders take the job and figure it out later. We priced a renovation, told the clients it was not good enough, and walked away from the fee. What happened next changed everything about how Carland Constructions builds.

The Forrest Passive House in Spotswood started as a $550,000 renovation brief that Carland Constructions refused to proceed with on performance grounds. Rather than deliver a standard renovation with a sustainable label on it, we proposed demolishing the existing home and building a certified Passive House from scratch. The clients said yes.

The Forrest Passive House achieved 0.41 ACH50 on the blower door test, making it one of the tightest new builds in Melbourne at the time.

What does it actually mean to be a sustainable builder in Melbourne?

We had just finished the Passive House tradesperson course and completed a project with Altereco Design in Kingsville. It was our first real taste of building better homes. At that point we called ourselves a sustainable builder. Melbourne had plenty of those. What it did not have many of was builders who could actually prove the buildings performed.

Altereco Design had a retrofit project in Spotswood and asked us to come meet the clients. I had a rule after a previous project. I wanted to interview clients as much as they interviewed me. Were these people I could knock on their door in 15 years and pop in for a coffee? They ticked every box. I even got grilled by their ten-year-old daughter and was more nervous answering her questions than the clients'.

We priced the renovation at $550,000. But something did not sit well. The performance gains were not enough and the comfort levels would have been like any other renovation. So we told the clients exactly that, potentially doing ourselves out of the project entirely, and asked for some time to think.

Somehow Altereco Design and Carland Constructions landed on the idea of knocking down the existing home and building a certified Passive House instead. We took the gamble, presented the idea, and could not read the reaction at all. I remember thinking: we will build a Passive House one day, just not this one.

A day later, the clients said: let's do it. I was speechless, which if you know me, almost never happens.

What does a high performance home actually cost to design and price properly?

We spent well over 250 hours on the preconstruction phase. Working on details, talking through performance, working through costings. A small preconstruction fee in the scheme of things barely touches the surface. If your builder is not charging for this stage, ask yourself what effort they are really putting in.

We went into this project with a basic understanding of Passive House and learned the rest through mistakes. We missed hundreds of hours of labour in the original costing, probably thousands across the full project. Drew from PassiveTech was vital to getting us across the line, feeding us ideas on insulating the service cavities, shortening the duct line, and cross-installing insulation in the subfloor. We got the project costed at around $900,000 in late 2019, then 2020 happened.

Timber costs went up 10% a week at the worst of COVID and it killed a lot of builders. We were lucky. We pulled the pin on a large job in Seddon and went all-in on high performance homes cold turkey, which in hindsight probably saved us. The Forrest Passive House was delayed by a health issue within the project team, not COVID, but the communication held and eventually we got there.

What does relocating an existing home instead of demolishing it actually involve?

Before we could build anything, we needed to say goodbye to the existing home. The site had a typical California bungalow on concrete stumps. Rather than demolish it, we found it a buyer and had it relocated.

I sat in my car with my popcorn thinking: there is absolutely no way this house clears those powerlines and fits through this street. The truck moved itself on hydraulics, like some futuristic transformer, and wiggled through spaces I did not think were physically possible. One morning there was a house on a block of land. By the next day it was gone. It does not solve the energy efficiency problems of wherever the home ends up. But it was saved from landfill, and that matters.

What did building our first certified Passive House teach us that no course ever could?

The blower door test was on the same day we had accidentally scheduled a client meeting. When the result came in at 0.41 ACH50, the clients looked at us and asked: is that good?

It was very good. 0.41 ACH50 is less than half the Passive House threshold of 0.6 ACH50, and roughly 46 times tighter than the average Melbourne home at 19 ACH50 (CSIRO / Australian Building Codes Board, 2016). We had built our first certified Passive House, proved the result with a physical test, and learned more in that one project than in the previous five years of building combined.

Five years on, Carland Constructions has now delivered five certified Passive Houses in Melbourne. Every single one starts with the same conversation: what does this home actually need to do, and how do we prove it did?

If you are about to spend $1.5 million on a new home and your builder has never had a blower door test done on one of their finished projects, what exactly are they selling you?