High performance homes in Melbourne, defined
High performance is the most abused phrase in Australian building. Everyone uses it and almost nobody defines it, so here's our definition, with the numbers to back it up.
When somebody tells you your home will be high performance, ask for the numbers. If they can't give you any, you have your answer.
Solar panels aren't high performance. Neither is a membrane.
Flick between the two and you'll see the difference between a house with some good products in it and a house that actually performs.
Solar panels
A power bill fix bolted onto a house that still leaks.
A membrane
One product doing one job.
Double glazing
Good glass in a wall that might still be letting the heat out around it.
Extra ceiling batts
A bit more insulation, with nobody checking how it went in.
A standard home is a collection of good intentions. Every one of these is worth having, but on its own it's just an ingredient.
Modelled
Every ingredient designed to work together in PHPP before anyone digs a hole.
Tested
Blower door tested mid build and at completion, with thermal imaging and measured ventilation.
Proven
Evidence you can keep, so the performance is a number, not a promise.
High performance is what happens when every ingredient works together and somebody measures the result.
Effectively a Passive House, without the certificate
Same physics, same modelling, same testing and same detailing. This is our minimum standard for what we call a high performance home, and if a project can't hit it, we don't call it high performance.
We're not putting this out to sell you anything. We're putting it out so you can't get confused.
This is our opinion, not a rule anybody handed us. It comes from six certified Passive Houses and counting, from new builds to EnerPHit, and from living in one ourselves.
Please treat this as a guide only. You should be working with the right team and the right consultants from the very start, and this page is simply an educational tool.All eleven, every time
This isn't a pick and choose list. It's either all of them, or don't bother calling your home high performance.
That's our take and we're not going to tiptoe around it. Tap any standard to see what it is, what we do and what the building code actually allows.
performance
What each one is, what we do, and what the code allows
Pick a standard. Each one has the same three parts, so you can see exactly where our minimum sits against the building code.
Thermally modelled
The difference between designing a house and guessing at one
What is it?
A simulation of your actual building, run against real Melbourne climate data, that predicts how it will behave before anyone digs a hole. It calculates what needs to be done so you can stay comfortable all year.
Change the glazing and you see the effect straight away. Add insulation and you can see whether it earned its money. Move a window and you find out what it cost you. Most importantly, it turns performance into a set of numbers you can argue with, rather than a promise you have to trust.
Our standard
Every project runs through the Passive House Planning Package (PHPP), not as a tick box at the end but as the tool that drives the design. It lets us cross reference performance against the cost of every change, so you can see what your money buys before you spend it.
What the code allows
An energy report done at design stage so the drawings can get through a building permit, and that's genuinely all it's meant to do. For most people it's a compliance check rather than a design tool, so nobody opens it again to work out how the house will actually behave or where the money is best spent.
Because it's a permit document, nothing in the process ever compares it against the finished house. A seven star rating tells you somebody modelled a seven star home, not that one got built.
Passive solar design
The sun is the biggest free energy source your block has
What is it?
Passive solar means shaping and pointing the building to collect the sun's heat in winter without paying a cent for it. It's which way the house faces, where the glass goes and how much of it, how deep the rooms are (sunlight only reaches so far in), and what the floors and walls are made of, because heavy materials soak up warmth during the day and give it back at night.
None of it involves a product or a machine. It's free, it's permanent, and it's decided in the first few weeks of design. Get it right and the house does a large part of the work for you forever. Get it wrong and you spend the next fifty years buying back energy you were being handed for free.
Our standard
Orientation, form and glazing set up to harvest winter sun, confirmed by the modelling rather than assumed. This one is usually out of our hands, which is exactly why we only work with architects and designers chasing the same result we are.
What the code allows
Nothing at all. Which way the house faces and where the glass ends up aren't requirements, they're just numbers typed into the energy report along with everything else.
A house pointed the wrong way still passes, and the cost of that decision never shows up as a failure on paper. It shows up every year afterwards in a bigger heating system and a bigger bill, for the whole life of the building.
Mechanical ventilation
Walls shouldn't breathe. People should.
What is it?
You'll hear that a house needs to breathe. It's rubbish. Mechanical ventilation with heat recovery delivers a constant, filtered supply of fresh air into the bedrooms and living spaces, and continuously pulls stale, humid air out of the kitchen, bathrooms and laundry. On the way out it strips the heat from the outgoing air and puts it into the incoming air, so you get fresh air without throwing your heating out the window.
In practice you never open a window for air quality again unless you feel like it. No pollen, no traffic noise, no smoke on a bad day, no bathroom that stays damp for six hours and no stuffy bedroom at 3am. It's the one clients notice most after moving in, it's usually the one they had no opinion about beforehand, and it's my favourite thing in our home.
Our standard
A centralised, ducted heat recovery unit supplying living and sleeping spaces and extracting from wet areas. It's commissioned and balanced at handover with actual flow rates measured and recorded, not set to whatever the installer felt like on the day. We work with Zehnder units through Fantech.
What the code allows
Exhaust fans that vent outside, and that's about the extent of it. In practice they aren't on timers, they're rarely moving anything like the amount of air they're supposed to, nobody ever puts a meter on one to find out what it actually pulls, and there are no filters on any of it.
There's no requirement for a whole house system, no heat recovery, and nothing anywhere that says somebody has to check it works properly on the day you move in.
Insulation that performs
A jumper with holes in it isn't really a jumper
What is it?
Insulation only works if it's continuous, uncompressed and in full contact with the surface it's insulating. The R-value printed on the bag is a laboratory figure, measured in perfect conditions. The second you squash a batt around a pipe, leave a gap at the top of a wall or let air wash through the back of it, that number falls, and it falls a long way. Wind washing alone can strip 30 to 50 percent off the effective value.
This standard is about the R-value that ends up in your wall, not the one on the packaging, and the difference between the two comes down entirely to how carefully it was installed.
Our standard
140 mm external studs at 600 centres, which fits around an R4.0 batt. Minimum R6.0 in the ceiling, R5.0 under a timber subfloor and minimum R2.5 in and around the perimeter of a slab, including the slab edge. Continuous, unbroken, uncompressed and protected from wind washing. Final figures always come from the modelling, so this is a solid starting point rather than a guess. We never guess it.
What the code allows
R-values on paper, and not many of them. In a typical build you're looking at R2.0 in the walls, maybe R2.5 at best, sitting in a 90 mm stud that physically can't hold any more than that, some R4 in the ceiling if you're lucky, and nothing at all in the slab or under the floor.
The code does say insulation has to be continuous and uncompressed, which is fair enough, but nobody ever inspects it. Insulation goes in after the frame check and gets covered before the final check, so whether it was installed properly comes down entirely to who did it and whether anybody happened to be watching.
Thermal bridge free
Don't leave the metal spoon in the pot
What is it?
A thermal bridge is any material that runs from the inside of your house to the outside and carries heat straight through, going around your insulation entirely. Remember Mum telling you not to leave the metal spoon in the pot, because you'd burn your hand on it? Same principle, bigger pot. Steel frames, uninsulated slab edges, balconies that run straight through the wall and structural posts are all spoons.
Thermal bridges do two things and both are bad. They leak energy, and they create cold surfaces on the inside face of your walls. Cold surfaces are where moisture condenses, and condensation is where mould starts. You can have perfect insulation across the entire building and still lose the argument at a single junction.
Our standard
Thermal bridges identified at design stage and detailed out. Timber framing rather than steel, insulated slab edges, and cantilevers, balconies and structural penetrations treated as the weak points they are. Where a bridge genuinely can't be removed, it gets modelled so we know exactly what it's costing.
What the code allows
Nothing, because there's no requirement anywhere that your home be thermal bridge free. Windows go wherever the drawings want them, steel and timber run straight from the inside of your house through to the outside, and there's no thinking at all about how you stop hot and cold spots forming through the walls.
That matters more than it sounds, because a cold spot is where moisture condenses and condensation is where mould starts. The code has no philosophy on the subject at all.
Airtight
A leaky house is a bucket with holes in the bottom
What is it?
Airtightness is about controlling where air moves. It isn't about sealing people in, which is the objection you'll hear from someone who hasn't done it. Every unsealed gap in a building is a hole. Heat leaves through it, and unfiltered outside air comes back in, bringing dust, pollen, traffic noise and, in summer, heat. You can pour heating in all day and never fill the bucket.
It matters more than almost anything else on the list because it's measurable. A blower door test gives you one number for the whole building, with nowhere to hide, no marketing angle and no product name that saves you. Either the house is tight or it isn't, and the fan tells you which.
Our standard
Under 1 ACH at 50 pascals on all new builds and under 3 ACH on retrofits (Passive House requires 0.6 ACH at the same pressure). The airtightness layer is designed as one unbroken line around the building before construction starts, not chased around with a caulking gun at the end.
What the code allows
Nothing, and more to the point, nothing gets checked. There's no maximum leakage figure for a house, just a list of things that should be sealed, with no number to hit and no test to prove any of it actually happened.
There's one strange rule worth knowing about. If you do test and come in under 5 air changes an hour, you then have to install mechanical ventilation, so the only real consequence of building tight is more work. Most builders simply never test, so it never comes up. It's the single biggest reason Australian homes feel draughty, while the rest of the world treats measuring it as completely normal.
Quality windows and doors
Your glazing sets the ceiling on the whole house
What is it?
Windows are the weakest part of any wall, always. Even a very good window performs several times worse than the wall it sits in. It's also where the marketing hides, because there are two different numbers: the U value for the glass on its own, and the U value for the whole window including the frame. The frame is usually the worst performing part, so the whole window number is always worse. Guess which one gets quoted.
Then there's where the window sits. A high performing window installed outside the insulation layer hands back a good chunk of what you paid for, because the junction around it becomes a cold bridge with a nice frame in the middle.
Our standard
Whole window U value specified, never glass only. Double glazing minimum, with high performance glass and warm edge spacers, in uPVC, timber or aluclad frames. Solar heat gain coefficient selected per elevation rather than one number applied to the whole house, and windows installed within the insulation layer. We don't use aluminium windows.
What the code allows
No minimum of any kind. No U value, no solar heat gain figure, nothing. The glass is just another number in the energy report, traded off against everything else, which is why single glazed aluminium is still legal here and still going into new homes.
The bigger gap is that almost nobody thinks about the airtightness of windows and doors. It's widely accepted that a bit of water will find its way through a window, and that isn't normal. These are the biggest holes you'll ever cut into your building envelope, so they need to be detailed and installed properly, and the code has nothing to say about it.
Water and moisture management
Keep the rain out and let the vapour out
What is it?
Two separate problems that get lumped together and shouldn't be. The first is liquid water from outside, rain and wind driven rain, which you keep out. The second is water vapour generated inside from showering, cooking, drying clothes and simply breathing, which you have to let out. A family of four puts several litres of moisture into the air every day.
Get the second one wrong and the vapour moves into the wall, hits a cold surface and turns back into water inside the structure where nobody can see it. The first you know about it is a smell, a stain or a building inspector with bad news, and by then it's been happening for years. The answer is a wall that can dry: a barrier that stops rain but lets vapour pass through, a cavity behind the cladding so air can move, and enough understanding of the physics to know which way the moisture is trying to travel in a Melbourne winter.
Our standard
A vapour permeable barrier with every join taped, working with a ventilated cavity so the structure can drain and dry. Air enters at the bottom, exits at the top and takes the moisture with it. Condensation risk is assessed on every project, not raised as a conversation and then forgotten. We only use Pro Clima membranes and tapes, and it's the best insurance policy you can have on a project.
What the code allows
Keeping water out of the building is the most important job a house has to do, and it's very rarely thought through properly. Homes are still going up with no membrane on the outside of the walls at all, and where there is one it's often not taped, not lapped into the wall frames correctly and the windows aren't taped off, so water finds every one of those gaps.
The code has improved here, and the membranes and roof ventilation are better than they were, but there's still nothing that requires anybody to sit down and work out whether your particular wall will actually stay dry.
Fully electric
Envelope first, systems second, solar last
What is it?
Two parts to this, and the second one matters more than people realise. First, no gas. Burning gas inside your home puts combustion products into the air your family breathes, and it locks you into a fuel with a rising price and a shrinking network. Everything runs on electricity, and a heat pump moves heat rather than making it, so it does the same job for a fraction of the energy.
Second, the order you do things in. Panels on a poorly built house just mean you're generating power in order to waste it. Fix the building and the amount of energy the house needs collapses, which means a smaller heating system, a smaller hot water unit and a much smaller bill before you've generated a single watt. Solar is the finishing touch on a house that barely needs it. It isn't the strategy.
Our standard
All electric appliances, with a CO2 heat pump for hot water. Solar is sized after the envelope is settled and the loads are known.
What the code allows
Victoria is ahead of the code on this one, because new homes needing a planning permit have had to be all electric since January 2024.
What nothing requires is doing it in the right order, so a poorly built house with a big solar array scores the same as a well built house with a small one, and the panels end up doing the work the walls should have done in the first place.
Tested and checked
Without evidence, you're relying on a builder's word
What is it?
The gap between what was specified and what actually got built is where performance quietly disappears, and testing is what closes it. A blower door test puts a large fan in a doorway, pressurises the house and measures exactly how much air is leaking, as a single number. A thermal imaging camera shows you the insulation gaps, the missed batts and the thermal bridges that are invisible to the naked eye. Checking the delivered windows against the specification catches the substitution nobody thought to mention, and measuring the ventilation flow rates confirms the system is doing what it was designed to do.
Every one of these produces evidence, and that's the point. Without it you're relying on a builder's word, and this page exists precisely because a builder's word on this subject is currently worth very little.
Our standard
A blower door test mid build, while the result can still be fixed, then again at completion. A thermal imaging walk through once the insulation is installed, written proof that the glazing delivered matches the glazing specified, ventilation flow rates measured and recorded at commissioning, and photographs at every stage of construction, so the parts you can no longer see are documented forever.
What the code allows
Four inspections, being footings, concrete, frame and final, and not one of them is a check on performance. Nobody verifies that the insulation, the glazing or the sealing matches what the energy report said, and while the building surveyor can ask for more, they aren't required to and almost never do.
So your house gets checked for compliance, and it never gets checked for performance.
Collaboration
Think of it like forming a band
What is it?
Every decision that determines whether a house performs is made early, on paper, long before anyone picks up a hammer: orientation, form, where the glass goes, how the envelope wraps the building and where the services run. By the time a builder is handed a finished set of drawings and asked for a price, most of those decisions are locked, and the ones that are wrong can only be fixed by spending money.
Early contractor engagement means we're in the room while those decisions are still open. We price honestly as the design develops rather than delivering a number at the end that nobody wants to hear, we find the buildability problems while they're still lines on a screen instead of a variation and a delay on site, and the architect gets a builder's brain in the design process. The magic doesn't happen when everyone turns up on the day and wings it. It happens because you've been rehearsing together since the very first note.
Our standard
We join the design team early, price openly from concept and work alongside the architect through design development. One team and one goal, with everyone aligned before a trade sets foot on site.
What the code allows
This one isn't a code requirement at all, and we're not going to pretend otherwise. Nothing in the building code says who should be in the room or when.
We've just found that the best projects are the ones with a team from the very start, everybody working towards one shared goal rather than pulling in different directions. On a high performance or Passive House build that goal sits out in the open, written down in numbers everybody can see, which makes it far easier to aim at, and that's exactly why this kind of build needs a high level of collaboration to come off.
Our minimum against a typical build
Airtightness and insulation are the two easiest places to see the gap, because both come with a number. Lower is better for airtightness. Higher is better for insulation.
The building code, our high performance standard and Passive House
The same eleven standards, laid out next to the minimum the code allows and the full Passive House standard, so you can see exactly where we sit.
| What the code allows | Carland Constructions high performance | Certified Passive House | |
|---|---|---|---|
| Thermal modelling | Energy report for the building permit, rarely reopened | PHPP drives the design, with cost checked against every change | PHPP, reviewed by an independent certifier |
| Passive solar | Not required | Orientation and glazing confirmed by the model | Confirmed by the model |
| Ventilation | Exhaust fans, no filters, no heat recovery | Ducted heat recovery, commissioned with measured flow rates | Ducted heat recovery, commissioned and verified |
| Wall insulation | Around R2.0 in 90 mm studs | R4.0 in 140 mm studs, continuous and protected from wind washing | Set by the model, continuous |
| Thermal bridges | Not considered | Detailed out at design stage, or modelled where unavoidable | Designed out or calculated |
| Airtightness | No limit and rarely tested | Under 1.0 ACH50 new builds, under 3.0 retrofits, tested twice | 0.6 ACH50 new builds, 1.0 for EnerPHit |
| Windows and doors | No minimum, single glazed aluminium allowed | Whole window U value, double glazed minimum, no aluminium, installed in the insulation layer | Performance set by the model, installed in the insulation layer |
| Water and moisture | No requirement to check the wall will stay dry | Pro Clima membranes, taped joins, ventilated cavity, condensation risk assessed | Assessed as part of the design |
| Energy | All electric for new homes needing a planning permit in Victoria | All electric, CO2 heat pump hot water, solar sized last | All electric, Plus and Premium add renewables |
| Testing | Four compliance inspections, none on performance | Blower door mid build and at completion, thermal imaging, glazing and ventilation checks, photos | Blower door test plus full evidence review |
| Collaboration | Not a code matter | Builder in the design team from concept | Strongly recommended |
| Certificate | No | No, our standard and our numbers | Yes, from an independent certifier |
A real PHPP verification from one of our projects
This is the kind of page that drives our design decisions. Every number is predicted before construction, then checked against the limits, so performance becomes something you can argue with rather than a promise you have to trust.
kWh/m² a year14≤ 15yes
kWh/m² a year3≤ 15yes
%0≤ 10yes
ACH500.4≤ 0.6yes
kWh/m² a year36≤ 45yes
High performance homes we've built in Melbourne
Not every project goes for Passive House certification. These homes were built to our high performance standard, and for many clients it's the sweet spot between cost and performance. We'll always tell you honestly whether full certification is worth it for your project.
Eleven questions to ask any builder
If you're not building with us, take this to your builder, your architect or your designer and ask which of the eleven they're actually doing and how they intend to prove it.
Copied, ready to paste- Will my home be thermally modelled in PHPP, and can I see the results?
- Has the modelling confirmed the orientation and glazing are working for passive solar?
- What ventilation system is going in, and will the flow rates be measured and recorded at handover?
- What R-values are going in the walls, ceiling, subfloor and slab edge, and who checks the install?
- Where are the thermal bridges in my design, and how are you dealing with each one?
- What airtightness number are you targeting, and when will you blower door test?
- What is the whole window U value, not just the glass, and are the windows sitting in the insulation layer?
- What membrane and tape system are you using, and has condensation risk been assessed for my walls?
- Is it all electric, and was the solar sized after the envelope was settled?
- What test results and photos will I receive as evidence at handover?
- When do you join the design team, and will you price the design as it develops?
High performance homes FAQ
What is a high performance home?
A high performance home is a home designed and built as one system, thermally modelled before it's built, tested after, and proven. At Carland Constructions it's effectively a Passive House without the certificate: the same physics, PHPP modelling, testing and detailing, with an airtightness target under 1.0 ACH50 on new builds. If a project can't hit all eleven of our standards, we don't call it high performance.
Is a high performance home the same as a Passive House?
Not quite. Our high performance standard uses the same modelling, detailing and testing as a Passive House but isn't independently certified, and our airtightness limit is under 1.0 ACH50 rather than the Passive House limit of 0.6. A certified Passive House is checked and signed off by an independent certifier.
How airtight is a high performance home?
Our minimum is under 1 air change an hour at 50 pascals on new builds and under 3 on retrofits, proven with a blower door test mid build and again at completion. For comparison, CSIRO's 2024 study of new Australian homes found an average of 6.86 ACH50, and 6.57 in Victoria.
Is a 7 star home a high performance home?
No. A 7 star rating is an energy report done at design stage to get a building permit. It tells you somebody modelled a seven star home, not that one got built, because nothing in the process tests the finished house for airtightness, insulation quality or ventilation.
Do solar panels make a home high performance?
No. Solar panels are a power bill fix bolted onto a house that may still leak. In a high performance home the envelope comes first, the systems second and solar last, so the panels are sized for a house that barely needs them.
Can an existing home be made high performance?
Yes. Our standard for retrofits is under 3 ACH50 with the same modelling, ventilation, insulation, moisture management and testing as a new build. Our Retrofit Rifle EnerPHit in Williamstown went further and reached 0.43 ACH50.
How much does a high performance home cost in Melbourne?
A high performance home costs more than a minimum standard build, mainly in insulation, windows, membranes, ventilation and the extra care and testing on site. How much more depends on the design and site, and the gap is smallest when the builder joins the design team early. We use PHPP to show what each change costs and what it buys, so your money goes where it counts.
Every one of these eleven is the minimum
That's what we consider the minimum before we're willing to call a home high performance. If you're planning a new build or an EnerPHit upgrade, the best time to talk to us is early, while the drawings are still lines on a screen and changing something costs a conversation instead of a variation.
Ask any builder for their numbers. If they can't give you any, you have your answer.
We'll show you ours. Tell us about your project and we'll tell you honestly what it would take.
Assumptions and terms
- This guide is based on NCC climate zone 6, specifically Melbourne, in a cool temperate climate.
- This isn't a pick and choose list. It's either all of them, or don't bother calling your home high performance. That's our take and we're not going to tiptoe around it.
- References to what the building code requires or allows are a plain English summary written for comparison and current at the date of publishing. The code changes, and this isn't a statement of code compliance or a substitute for advice from your building surveyor.
- Descriptions of what a typical home is built to are general observations of what we commonly see in the market. They aren't statements about any particular builder, product, project or company.
- Performance figures are design targets and modelled outcomes. Actual performance depends on how the finished home is built, commissioned, occupied and maintained, and nothing here is a guarantee of a result on your project.
- This advice is general in nature and isn't a site specific design, engineering or building assessment for your property. The minimum standards assume a cool temperate climate and may need altering for other climate zones or unique site conditions.
- These specifications are based on general industry best practice and thermal modelling outputs for high performance homes. They're intended for conceptual and informational purposes only, and you should always consult experts when applying any of this to your project.
- You must seek and rely solely on the advice of independent, qualified professionals engaged for your project, including architects, structural engineers, builders, certifiers, energy consultants and mechanical engineers. Those professionals are responsible for adapting these general principles into a compliant and constructible design for your site.
- Following these standards doesn't automatically guarantee compliance with all Australian building codes and regulations. The final design and construction must meet or exceed the mandatory requirements of the relevant council and regulatory authorities.
- Passive House and EnerPHit are independently certified standards. We build to them, we don't certify them. Certification is issued by an independent certifier, not by us.
- Nothing on this page is a quote, an estimate, a fixed price or an offer to enter into a contract.
- Images are of our own projects and are indicative only.
- © 2026 Carland Constructions. All rights reserved. This content is protected by copyright under the Copyright Act 1968 (Cth) and other applicable Australian intellectual property laws, and is owned exclusively by Carland Constructions. No part of it may be reproduced, adapted, stored in a retrieval system or distributed in any form or by any means without the prior written consent of Carland Constructions.