How do you know an “eco home” actually performs?
Ask for the numbers. Green claims are cheap; measured performance is rare.
Our benchmark is the certified Passive House standard, because it’s the one approach where an independent certifier verifies the result: heating demand of 15 kWh/m²·yr or less, airtightness of 0.6 air changes per hour or better, and total primary energy of 60 kWh/m²·yr or less. No numbers, no certificate. We explain the whole standard in what certified Passive House means.
Then ask for proof. Bluebush, our certified Passive House Classic at Blackmans Bay, came in under all three limits: 0.5 air changes per hour, a heating demand of 10 kWh/m²·yr, and a PER of 48 — and was named HIA Australian GreenSmart Home of the Year 2026 at the 2026 HIA Australian GreenSmart Awards (see the awards). A certified Passive House needs roughly 80–90% less heating energy than a typical build — a certified figure, not a brochure one. Behind it sits our certified Passive House team: 13 Certified Passive House Tradespersons and around $8 million of Passive House projects delivered.
Materials matter too. Our project Asgard won a national Master Builders award for Best Use of Australian Made Products — locally made materials mean shorter supply chains and products proven in this climate.
If you want a checklist that isn’t ours, we’re members of the Sustainable Builders Alliance, and its free Roadmap to Net Zero Homes sets out the five steps in plain terms — design, materials, construction, appliances, generation. It is a good way to test any builder’s claims, including ours. We’ve written about why we joined.
Is a low-energy home also a healthier home?
Yes, and it’s the same fabric doing both jobs. Continuous insulation keeps interior surfaces warm, so condensation never forms on them. Airtightness plus controlled ventilation replaces damp, stale air with filtered fresh air all day. The construction that cuts your energy use is the construction that removes the moisture mould needs to grow — we’ve written up the building science in why Tasmanian homes get cold, damp and mouldy. That’s why every eco home we build is, by the same measure, a healthy home.
What about the carbon in the building itself?
There are two carbons in a home. Operational carbon is what it emits while you live in it — and that is the one we have driven close to nothing. Embodied carbon is what was released making, moving and assembling the materials before you moved in. As homes get better at the first, the second becomes the larger share of the lifetime total.
Three things we do that reduce it, and one thing we don’t.
We build in timber. Concrete and steel are mined, smelted and fired; a timber frame is grown, and the carbon the tree took up stays locked in the structure for as long as the building stands. It is the only major structural material that is renewable. That is a straightforward advantage of light timber-framed construction, and it is how nearly every home we build is framed.
We insulate rather than heat. Insulation, membranes and good glazing carry embodied carbon of their own, but they are small, one-off costs against decades of avoided heating. At Bluebush that meant Knauf Earthwool in the walls, CSR Bradford in the ceiling, a Pro Clima airtightness system taped at every joint, and Unilux triple glazing with a whole-window U-value of 0.75. The full build-up is published in the Bluebush case study — make of it what you like, and compare it with anyone.
We build once. A home that lasts a century amortises its embodied carbon over a century. A home that needs re-cladding in fifteen years and rebuilding in forty has paid that cost three times. Durability is a carbon strategy, not just a quality one.
And what we don’t do: we don’t commission a life-cycle assessment on every home, so we don’t publish an embodied-carbon figure for our builds. Plenty of builders will quote you one. We would rather tell you exactly what we use and let you check it than put a number in front of you that we have not measured.
All-electric, and what that actually means
Bluebush has no gas connection. Hot water is an air-source heat pump; heating and cooling are heat pumps; cooking is electric. Heat pumps move heat rather than making it, which is why they return several units of heat per unit of electricity.
The reason this matters beyond the bill: an all-electric home decarbonises on its own. Every year the grid gets cleaner, your home gets cleaner, and you do nothing. A gas appliance installed today burns gas for its entire life no matter what happens around it.
And the number worth sitting with — Bluebush met the Passive House renewable primary energy target of 60 kWh/m²·yr with a result of 48, and zero solar generation. The envelope and the plant did it alone. Panels would only improve it.
Do eco homes cost more — or less?
More to build, less to run. Honestly: our custom homes typically start around $5,000 per square metre in 2026, and full Passive House certification adds roughly 15%. What comes back is the running cost. Heating is the biggest lever on a Tasmanian power bill — see what actually drives your heating bills — and a certified Passive House cuts that demand by 80–90%. Put your own bills through the Passive House savings calculator and see what the fabric pays back, year after year, for as long as the home stands.
Zanetto Builders holds Tasmanian building licence CC7565 and is a member of Master Builders Tasmania, the HIA and the Australian Passive House Association — a team recognised with 26 state and national building awards, including the 2026 HIA Australian GreenSmart Home of the Year. To get started, request your 48-hour feasibility.
