Certified Passivhaus or “built to Passivhaus principles” — what’s the difference?
One is measured. The other is a promise.
Any builder can say a home follows Passivhaus principles — nobody checks. A certified Passive House has to prove itself to an independent certifier against three hard limits: heating demand of 15 kWh/m² a year or less, airtightness of 0.6 air changes per hour or better under a blower-door test, and total primary energy of 60 kWh/m²·yr or less. Miss one number and there is no certificate, no matter how good the home looks. We’ve laid the standard out in plain English in what certified Passivhaus actually means, and our Passivhaus guide covers how the pieces work together.
We invested in the qualifications, not just the language. Our certified Passive House team includes 13 Certified Passive House Tradespersons, and we’ve delivered around $8 million of Passivhaus projects. We’re members of the Australian Passive House Association. That’s trained, tested capability on the tools — not a line on a brochure.
What has a Zanetto Passivhaus actually achieved?
Bluebush, our certified Passive House Classic at Blackmans Bay, was designed with Maxa Design and independently certified by Jason Quinn of Sustainable Engineering Ltd. The tested results:
- Airtightness: 0.5 air changes per hour, against a limit of 0.6
- Heating demand: 10 kWh/m² a year, against a limit of 15
- Primary energy (PER): 48 kWh/m²·yr, against a limit of 60
In the owner’s words, it’s only the third certified Passivhaus in Tasmania — and at the 2026 HIA Australian GreenSmart Awards it was named HIA Australian GreenSmart Home of the Year 2026 and HIA Australian GreenSmart Custom Built Home 2026, the national program’s highest honour (see the awards). A certified Passivhaus needs roughly 80–90% less heating energy than a typical build — in this climate, that’s the difference between fighting winter and ignoring it. If cold rooms, condensation and mould are what’s pushing you to build, read why Tasmanian homes get cold and damp. Certification is the verified fix, not a hopeful one.
What does a certified Passivhaus cost in Tasmania?
Our custom homes typically start around $5,000 per square metre in 2026, and certification adds roughly 15% — most of it in the envelope, the glazing and the ventilation system. We’ve broken the whole premium down honestly in what a certified Passivhaus costs in Tasmania. What you get back is measurable. Put your own power bills through the Passivhaus savings calculator, or read our full guide to the cost to build in Tasmania.
When you want a real number for your own project, our 48-hour feasibility lands within 10% of true build cost — certified Passivhaus included.
What a passive house builder actually does differently
The gap between a passive house and a good conventional home isn’t a product you bolt on. It’s a sequence of decisions, most of them made before anyone turns a sod, and then executed with a level of precision that ordinary construction doesn’t demand. Five things change.
The design is modelled, not estimated. Every certified project is built in PHPP — the Passive House Planning Package — which predicts the home’s energy demand from its actual geometry, orientation, glazing, insulation and ventilation. If the model says the home misses, we change the design before it’s built, not after you’ve lived through a winter in it.
The envelope is continuous. Insulation runs unbroken around the whole heated volume, and every place a structural element would otherwise bridge that layer gets detailed out. Thermal bridges are where conventional Australian construction quietly loses much of its theoretical performance — we’ve written about how thermal bridging gets fixed in practice.
Airtightness is built, then tested. An airtight layer is planned as a single continuous surface and taped, sealed and protected through the whole build. Then a blower door proves it. There is no way to fake this number and no way to fix it cheaply at the end, which is why it separates builders who have done it from builders who talk about it.
Ventilation is mechanical and constant. Because the home doesn’t leak, fresh air is delivered deliberately — a heat-recovery ventilation system supplies filtered outside air to bedrooms and living areas and extracts from wet areas, recovering most of the warmth from the air it throws away. This is the part homeowners underestimate and then love most: clean, filtered, never-stuffy air, all year, without opening a window to a Tasmanian July.
The windows are a system, not a line item. Passive house glazing is typically triple-glazed with insulated frames and warm-edge spacers, specified per elevation. Good passive house windows transmit a fraction of the heat a standard Australian window does — which is why a certified home can have generous glass and still hold temperature overnight.
What it’s like to live in one
The numbers are the proof, but they aren’t the experience. In a certified home the indoor temperature moves slowly and stays in a narrow band, so rooms feel the same in the morning as they did at bedtime. There are no cold corners and no draughts, because there is nowhere for air to leak in. The air is filtered, which matters if you have hay fever, asthma or a wood-heater neighbour.
It is also quiet. The same airtight, heavily insulated envelope that keeps heat in keeps road and wind noise out — an effect nobody buys a passive house for and everybody mentions afterwards.
And the running costs stop being a variable you worry about. A certified home needs roughly 80–90% less heating energy than a typical build, which in this climate means a small system running gently rather than a large one fighting the weather. Put your own bills through the Passivhaus savings calculator to see what that looks like for you.
Passive house myths worth clearing up
“You can’t open the windows.” You can, whenever you like. The ventilation system means you don’t need to, but nothing about the standard seals a house shut.
“It’s only for cold climates.” The standard is climate-neutral — the same physics that keeps heat in during a Tasmanian winter keeps it out in summer, with shading and ventilation strategy doing the work.
“It has to look like a box.” Form helps efficiency, so a compact shape is easier to certify. But the standard sets performance targets, not an aesthetic. Our certified work was designed with architects and looks like it.
“The technology will date.” The envelope — insulation, airtightness, glazing — is passive and has no moving parts. The ventilation unit is the one serviceable component, and it’s a filter change and an eventual replacement, like any appliance.
“Certification is just paperwork.” Certification is the only thing that converts a claim into a measured fact. It is precisely the paperwork that a builder who missed the targets cannot produce.
Choosing a passive house company: what separates one from another
Search for a passive house company and you will find builders describing themselves in almost identical language. The gap between them is not vocabulary, it is evidence — and there are only three questions that matter.
Has this builder actually certified a home? Not designed one to the standard, not built one to principles — certified, audited and issued a certificate. Ask who the certifier was. A real answer names a person; ours is Jason Quinn of Sustainable Engineering Ltd.
Who on the team holds a certification, by name? The Passive House Institute certifies individual tradespeople, not just companies. We hold 13 Certified Passive House Tradespersons — the deepest bench in Tasmania — because airtightness is executed on the tools, not in a meeting.
What was the last blower-door result? It is a pass/fail number that no marketing copy can soften. Ours was 0.5 air changes per hour against a 0.6 limit.
Plenty of passive builders can answer one of those three. Ask for all three, of everyone you shortlist, including us.
Passive house builders near you, across Tasmania
We build certified and high-performance homes statewide from three bases — our head office at St Leonards near Launceston, and offices serving Hobart and the East Coast from Cambridge and St Helens. In practice that covers the North and Tamar Valley, the South and the Channel, the north-west coast around Devonport and Burnie, and the East Coast from Bicheno to St Helens.
Tasmania’s climate varies more than its size suggests — a frost hollow at Westbury, a wind-exposed coastal block at Falmouth and a steep southern site above the Derwent are three different performance problems. Every project is modelled for its own site rather than to a standard detail set.
Passive house or Passivhaus — same standard, two spellings
You’ll see it written both ways. “Passivhaus” is the original German name; “passive house” is its English translation — they name exactly the same internationally recognised performance standard. So whether you’re searching for a passive house builder, a passive home builder, or a Passivhaus builder in Tasmania, you’re after the same thing: a team that can design and construct to the standard and then prove it with an independent certificate. That’s precisely what we do — and why we’re the state’s most awarded certified team.
Zanetto Builders holds Tasmanian building licence CC7565 and is a member of Master Builders Tasmania, the HIA, and the Australian Passive House Association. Our certified passive house work earned the 2026 HIA Australian GreenSmart Home of the Year — see the full list on our awards page, or start your own project with a 48-hour feasibility.
