Straight answers about
passive house homes.
We have been involved in more than 10 passive house projects across Sydney. These are the questions families ask us most, answered directly.
Your questions
If your question is not listed here, contact us directly. We respond to every enquiry within one business day.
What is a passive house and how is it different from a standard home?
A passive house is built to the Passive House Institute (PHI) standard, the most stringent energy and comfort standard in residential construction. Unlike a standard home, which relies on heating and cooling systems to maintain comfort, a passive house stays at 20–25°C year-round through a combination of continuous insulation, airtightness, double-glazed windows, and a heat recovery ventilation (HRV) system. The result is 80% less energy use, no mould, no dust, and continuous fresh filtered air. Read the full explainer.
How much does a passive house cost to build in Sydney?
Marvel Homes builds passive houses with budgets from $900K to $2M+. A certified passive house typically costs 15 to 20% more to build than a standard home of the same size, but the long-term savings on energy bills and the far lower heating and cooling demand offset a significant portion of this. We do not provide ballpark figures without reviewing your site, brief, and planning constraints.
How long does it take to build a passive house?
The construction phase of a Marvel Homes passive house takes around 62 weeks. Before that, design takes around 6 weeks, approvals run from six weeks for a CDC to four months for a council DA, and colour and material selections take around 4 weeks. The full timeline depends on the site, the approval pathway, and the brief.
Does a passive house need air conditioning?
It still has air conditioning, but it needs far less of it than a standard home. The building envelope, insulation, airtightness, and glazing does most of the thermal work, and the HRV system handles fresh air and dehumidification. In Sydney's climate the heating and cooling runs only during the hottest and coldest stretches of the year, and the system is sized to each home through PHPP energy modelling rather than a rule of thumb.
What is the 0.6 ACH airtightness standard?
Airtightness is tested by a blower door test, which pressurises the building and measures how much air leaks through gaps in the envelope per hour. The passive house standard requires 0.6 ACH (air changes per hour) or below at 50 pascals of pressure. A typical new Australian home tests around 15 ACH (CSIRO), meaning it leaks more than 20 times as much air as a passive house. Leaky buildings are uncomfortable, dusty, and expensive to heat and cool.
What is a heat recovery ventilation (HRV) system?
An HRV system continuously extracts stale air from wet areas (bathrooms, laundry, kitchen) and replaces it with fresh outdoor air. The heat exchanger inside the unit recovers 85–95% of the thermal energy from the outgoing air and transfers it to the incoming air, so you get constant fresh air without losing the heat you paid for. This eliminates the mould, condensation, and indoor pollutants that accumulate in standard homes with intermittent ventilation.
Can I get PHI certification for my passive house in Australia?
Yes. Marvel Homes builds to PHI certification standard. The certification process involves energy modelling (PHPP), third-party verification by an accredited certifier, and a blower door test at practical completion. Not every client requires the certificate, but every Marvel Homes build is designed and built to meet it.
Is passive house worth it in Sydney's climate?
Yes. Sydney's climate is often cited as 'mild', but it has cold winters, humid summers, and high cooling demands in Western Sydney. A passive house dramatically reduces both heating and cooling demand, runs its heating and cooling far less than a standard home, and provides continuous fresh air that standard homes never achieve. The investment pays back in comfort, health, and energy costs over the life of the home.
How does passive house relate to the 7-star NatHERS rating?
The 7-star NatHERS rating is a minimum compliance target under the NCC. Passive house (PHI) certification is approximately 4–5 times more stringent. A 7-star home still relies heavily on mechanical heating and cooling to meet the modelled performance. A passive house stays comfortable on a fraction of that. For a detailed comparison, see our page on passive house vs 7-star NatHERS.
Can you build a passive house on a sloping, narrow, or complex site in Sydney?
Yes. Marvel Homes builds on sloping blocks (2–4m+ fall), narrow lots (7.5m+), corner blocks, and wide-shallow lots across Sydney. The engineering and construction backgrounds of our principals mean site complexity is resolved during design, not discovered at the frame stage.
Go deeper
Longer answers to the bigger questions.
How much should I budget for a passive house?
An honest read on Sydney build costs, from $900K, and why ballpark figures without a site review mislead.
Read the answer→Can you apply passive house principles within our budget?
The three levels of specification, from full PHI certification to high-performance, and what changes between them.
Read the answer→Next step
Ready to talk about your site?
We build five to eight homes a year, by choice. Send us your block and brief and we will tell you quickly whether it is a fit.
See how we build