Led by a Certified Passivhaus Tradesperson. Homes designed, modelled and tested so the finished house performs the way the drawings promise: steady temperature, filtered fresh air, no draughts, no condensation.
AGATHĒ builds architectural and Passivhaus homes from Sydney's north to Newcastle. Our founder, Mitch Chan, holds the Certified Passivhaus Tradesperson credential, and the business is a member of the Australian Passivhaus Association. Passivhaus is unforgiving of shortcuts: certification is won or lost in the junctions, the membranes and the order the trades go in. So building science leads the build itself, not just the brochure. Airtightness is checked while the walls are open, not hoped for at handover.
Where our certified work stands. Certified Passivhaus is the direction we are working in, and we would rather say that plainly than imply a certificate we do not yet hold. What we bring today is the credential, the membership, the testing discipline, and a pre-construction process built to carry a certified project from first sketch to final pressure test.
Our Passivhaus work sits inside a wider practice of healthy, high-performance building, so the same care with moisture, ventilation and material selection runs through every home we deliver.
A 34-minute conversation between Mitch and Andy Marlow of Envirotecture on why Passivhaus matters in an Australian climate, what it changes about how a home is designed, and what people get wrong about it. Press play when you have the time; nothing starts on its own.
Plenty of homes are described as energy efficient. A certified Passivhaus is different in kind: the home is modelled against the international Passivhaus standard before it is built, constructed to hit those numbers, then physically tested (including a pressure test of the finished building envelope) and independently certified. The certificate is not a marketing phrase. It is a third party confirming the home performs exactly as designed.
What that performance feels like day to day: the whole home stays within a few degrees year-round without leaning on air conditioning, the air is continuously filtered and fresh, and the house is quiet, free of draughts and condensation, and far cheaper to run.
Every certified Passivhaus stands on the same five pillars, engineered to work together from the first sketch.
A complete thermal blanket around the home (floors, walls and roof), so indoor comfort stops depending on the weather.
The building fabric is sealed and pressure-tested, keeping conditioned air in and wind-driven moisture out of the structure.
Independently certified double or triple glazing that holds the views without the heat loss, glare or winter cold spots.
Junctions designed so heat has no shortcut through the structure: the detail work that prevents cold surfaces and condensation.
Continuous filtered fresh air with heat recovery, so the home stays dry, healthy and mould-free with the windows closed or open.
Most people researching Passivhaus want a number first. A fair one depends on the design, the site and how far you take the standard, so we talk ranges in the first conversation rather than on a web page. These are the things that move the cost most, roughly in order.
A compact two-storey form is cheaper to insulate and seal per square metre than a sprawling single level with many corners. Simple shapes reward you twice: less envelope, fewer junctions.
Certified windows and doors are the largest single uplift over a standard build. How much glass, which way it faces and whether it is double or triple glazed matter more than the brand on the frame.
Airtightness and thermal-bridge-free junctions are mostly labour and sequencing, not materials. This is where a trained crew earns its place and where an untrained one quietly costs you the certificate.
A heat-recovery ventilation system, the ducting to serve it and the space to house it, sized to the home rather than bolted on at the end.
Energy modelling at design stage, pressure testing during and after the build, and the certifier's review. A modest line against the whole build, and the proof that the rest was done properly.
Slope, access, bushfire rating and structural ambition cost what they cost whether or not the home is Passivhaus. They are usually the bigger swing in the budget.
Heating and cooling bills that are a fraction of a standard home's, a house that holds its temperature through a heatwave or a cold snap, and air that is filtered every hour of the year.
Want to know where your project is likely to sit? Bring your sketches, your site and your budget to a first conversation and we will talk it through with you before anything is drawn in detail. The certification process, and what the certificate itself costs, is here.
Whether you are at the early thinking stage or ready to move, we are happy to have a clear, straight conversation. No obligation. We will tell you if we are not the right fit.
Prefer to talk it through first? Call us and one of the team will pick up or call you back the same day.
A Home That Feels Right is our free guide for families planning to build or renovate. It is written for the research stage: the questions worth asking before a single drawing is paid for. We email it to you. No call, no follow-up unless you ask for one.
We work alongside your architect from the first sketch, so Passivhaus performance is designed in (orientation, form, glazing and structure), not bolted on later at cost.
Our structured pre-construction process aligns the design, the budget and the certification goal before anything is locked in. You will know where your project sits early, with allowances set clearly and the proposal fully specified.
Builder-led delivery with the building science supervised at every stage: envelope testing during the build, certified components installed as designed, and a site culture that treats the airtightness layer as carefully as the finishes.
The completed home is tested and the evidence submitted for independent certification: the proof, in writing, that you got what was designed. See how certification runs, and what it costs.
Four good places to continue: Passivhaus certification in NSW: the process and what it costs, how a Passivhaus is designed, and why the order matters, building a Passivhaus in Sydney: what our climate asks of the standard, and the question we hear most, can you open the windows in a Passivhaus?
Builder-led delivery of custom homes and Passivhaus builds, managed end to end.
Start the right way with our PAC-certified process, aligning design, budget and timeline before you build.
We work alongside your architect from the first sketch, so Passivhaus performance is designed in, not bolted on.
Scandinavian-inspired homes and cabins built to a healthy, high-performance standard.
Partial to full-scale renovations that transform your existing spaces into healthy, beautiful family living environments.
From design to delivery, we manage every detail for a smooth, on-time, on-budget build.