What does sustainable home design actually mean in Melbourne?

By Barbara Yerondais
Sep 25, 2026

Answering: What does sustainable home design actually mean in Melbourne beyond certification?

Estimated reading time: 10 min read

You have three quotes on the kitchen table. One leads with Passive House. One leads with seven stars. One leads with net zero. None of them can tell you whether the west-facing bedroom still bakes in a Melbourne February, or whether the house copes when you throw the windows open on a cool change. Before you buy a score, find out what the design does on your block.

Sustainable home design in Melbourne, beyond certification, is a house that stays comfortable in heat and cold on less energy, with windows you can open and fabric that works on your actual site. Since 1 May 2024 a new Victorian home on the NatHERS path must reach seven stars and a whole-of-home rating of at least 60. That is the NatHERS floor, not the goal. A quote that leads with seven stars is leading with the minimum.

BY Projects Architecture has delivered 400+ projects across Victoria. After 35+ years in practice, Barbara Yerondais, FRAIA, treats building-science tools as a guide: borrow the insulation, draught control, glazing, orientation and thermal mass, then keep mixed-mode ventilation so the house can breathe. A sealed box tuned to a number is the anti-pattern. Our heritage articles cover overlay fabric. The same science applies to ordinary Melbourne houses and new blocks.

Key Insights

  • From 1 May 2024 a new Victorian home on the NatHERS path must reach seven stars and a whole-of-home rating of at least 60. That is the NatHERS floor.
  • A planning permit also asks how the design considered energy, water, waste, transport, cooling and greening, biodiversity, and air and noise.
  • A NatHERS rating is a design-stage simulation. It does not account for airtightness as built.
  • Melbourne needs summer shade as much as winter sun: north living under eaves, shaded east and west glass, bedrooms off the west, openings that can cross-ventilate.
  • Spend in this order: plan and orient, shade then glaze, insulate and seal, ventilate on purpose, then systems, then solar.
  • BY Projects borrows Passive House building science and rejects certification-chasing. A standard is a guide, not the goal.

Sustainable is not one stamp. Three layers sit on a Melbourne house, and each is checked by someone different.

Layer What it measures Who checks it What it cannot see
NatHERS and the NCC energy rules Modelled heating and cooling demand, plus a whole-of-home appliance budget NatHERS assessor and registered building surveyor Airtightness as built, construction workmanship, water, landscape, embodied carbon, how the house is lived in
Planning ESD Energy, water, waste, transport, cooling and greening, biodiversity, air and noise; local tools such as BESS Council, when a planning permit is required Construction quality after the permit, lived comfort
Lived performance Shade, ventilation, draughts, retained fabric, how the house is lived in You, your architect and, if commissioned, a blower-door test Nothing a certificate can substitute for on your block

On this page

Seven stars is the floor, and council asks a wider question

A new Victorian home must meet the energy efficiency requirements in National Construction Code Volume Two. The common route is a NatHERS assessment. From 1 May 2024 that path requires seven stars and a whole-of-home rating of not less than 60.

If you are extending or substantially renovating, current energy rules may apply. The Building and Plumbing Commission gives the example of work to more than 50 per cent of the home, and says a registered building surveyor decides how far compliance reaches. BY Projects is not a building surveyor. Ask one early.

A planning permit asks more than stars. After Amendment VC216, a development that needs a planning permit must show how it considered energy, water, waste, transport, cooling and greening, biodiversity, and air and noise. Councils add local ESD policies. Boroondara requires ten ESD categories. Larger projects must lodge an ESD report, a BESS scorecard and a Clause 53.18 stormwater plan; two or more dwellings need a stormwater plan. Best practice on that page includes retaining the existing structure where possible and keeping canopy trees.

Read your own council’s ESD policy before the design is fixed. For overlay work, start with heritage architects in Melbourne.

What a certificate cannot see

A NatHERS rating is a design-stage computer simulation of heating and cooling need. More stars means less modelled energy to stay comfortable. That is a useful check on a design. It is not a photograph of the finished house.

CSIRO blower-door tested 233 recently built dwellings, including homes in Melbourne. Average air permeability was 6.9 cubic metres per hour per square metre at 50 pascals. About 5 was identified as ideal for a new dwelling. Older homes are often around 30. Poor airtightness can lift bills by up to 20 per cent. NatHERS does not account for airtightness. The National Construction Code does not set a leakage rate for ordinary houses. It does require buildings to achieve thermal performance by sealing against air leakage. A blower-door test is good practice. It is not a general Victorian legal requirement.

Tightness without a ventilation plan creates the opposite problem. CSIRO warns that very airtight homes without controlled ventilation risk condensation and mould. Plan ventilation as deliberately as you plan sealing.

That gap is why sustainable home design in Melbourne has to cover ventilation and sealing, not only the star rating. BY Projects will not chase a Passive House or NatHERS score as the point of the job. The practice borrows the science and keeps mixed-mode living: openable windows, air that can move, older fabric that must breathe. For overlay fabric, see Passive House in a heritage home.

Melbourne needs summer shade as much as winter sun

YourHome’s orientation guidance for temperate climates is to balance winter sun and summer shade. Put living to the north under eaves. Limit and shade east and west glass. Keep bedrooms off the west where you can. Provide openings that can cross-ventilate when a cool change arrives. Hotter summers and more frequent extreme heatwaves make passive cooling more important.

Check which rooms take the afternoon sun before anything is drawn. On a new home, orientation comes before the plan. Keep established trees where you can. Boroondara lists canopy retention as best practice.

Retention can be the climate move. At the Altona transformation, a mid-century triple-fronted brick veneer, about 60 years old, was kept. The rear patio was enclosed as lounge and dining under clerestory windows for northern light, and the original living room became a fourth bedroom. Three bedrooms became four without full demolition. The same instinct applies to an extension or a renovation.

Fabric first, then systems, then solar

CSIRO’s analysis of 102,000 Australian homes found that improving airtightness and insulation in roofs, walls and floors first gets the most from electrification and rooftop solar. Across Australia, weatherboard and brick veneer houses make up nearly half the housing stock and sit among the worst performers.

Spend in this order, because each step makes the next one smaller:

  1. Plan and orient. Living to the north; bedrooms off the worst west glass.
  2. Shade, then glaze. Eaves, external blinds and trees beat an oversized cooling unit.
  3. Insulate and seal the whole house, including the parts you are not remodelling.
  4. Ventilate on purpose. Decide which windows open and how air crosses the plan.
  5. Size systems to the improved house, including heat-pump heating and hot water.
  6. Then solar, once demand is lower.

From January 2027 new homes must be built all-electric. The published standards include exemptions where electrification or compliance is impractical or costly. From 1 March 2027, if a gas hot-water appliance in an owner-occupied home fails and cannot be repaired, it must be replaced with an electric alternative. That rule does not require owner-occupiers to replace gas space heating or cooking. Reserve plant space, drainage, power and acoustic separation now.

Price comfort moves beside the kitchen. The practice works on a fixed, staged fee: schematics first, then two drawings (what the budget achieves and what the full wish list costs) and a scope list. Put fabric moves on that list so they are chosen, not leftover.

Five questions to put to any sustainable quote

Ask for the answer as a drawing, not a slogan.

  1. Where does living sit relative to north, and how is east and west glass shaded in February?
  2. Which windows open, and how does air move through the house on a cool change?
  3. Is the existing house in scope, and is an airtightness test part of the job?
  4. When is the NatHERS rating done, and what does your council’s ESD policy ask for this permit?
  5. Where do the heat-pump hot water and any future solar go, including drainage and noise?

If a quote cannot answer those five on your block, it is selling a label.

Closing

Sustainable home design in Melbourne is a house that stays comfortable in heat and cold on less energy, with air you can choose to move. The order is site and life, then fabric, then systems. Standards are a guide. If you want that order applied to your block, book a one-hour Feasibility Session with Barbara Yerondais, FRAIA, in person or on Zoom. The session works through logistics, budget and planning timelines, including thermal performance alongside overlays and structure.

Frequently asked questions about sustainable design in Melbourne

Q: Is a 7-star home in Melbourne automatically a sustainable home?

A: It is a compliant one on the NatHERS path. From 1 May 2024 a new Victorian home using that path must reach seven stars and a whole-of-home rating of at least 60. That rating is a design-stage simulation of heating and cooling need. It does not measure airtightness as built, water, trees or how the house is used. CSIRO’s tests of 233 new homes found average leakiness above the rate it called ideal, and warned that very tight homes without planned ventilation risk condensation and mould. Sustainable home design in Melbourne covers those layers. BY Projects uses the rating as a check on a design, not as the goal.

Q: When should sustainability decisions be made in a renovation or extension?

A: Before the plan locks orientation, glass and what you keep of the existing house. Extensions and substantial renovations may need to meet current energy rules; a registered building surveyor decides how far that reaches. If the work also needs a planning permit, council ESD policy sits beside the building code, and tools such as BESS or a stormwater plan can be required. Fabric moves are cheap only while they are still lines on a drawing.

Q: What happens in a Feasibility Session if sustainability matters to us?

A: It is a full one-hour session, in person or on Zoom, with Barbara Yerondais, FRAIA. It works through logistics, budget and planning timelines, including thermal performance alongside overlays and structure where they apply. There is no obligation to engage BY Projects afterwards. Book it on the Feasibility Session page.

Citations

SCHEDULE A FEASIBILITY SESSION
SEE OUR PROCESS →

About the Author

Barbara Yerondais, FRAIA, is the founder of BY Projects Architecture. With 35+ years of experience, she specializes in sustainable, community-focused design and heritage restoration. A dedicated mentor and rower, Barbara balances her high-impact Melbourne practice with a passion for social inclusion and passive, energy-saving design.

INDEX

Start the Conversation

Every project begins with a deep inquiry into site, heritage, and vision. Let’s discuss the strategic potential of your next work.

SCHEDULE A FEASIBILITY SESSION →

A PRELIMINARY CONSULTATION TO EVALUATE HERITAGE CONSTRAINTS, SITE POTENTIAL, AND PROJECT FEASIBILITY.