NatHERS Energy Assessments for New Homes and Renovations
Every new home and major renovation in Australia needs to meet the energy efficiency requirements of the National Construction Code, and a NatHERS assessment is the most common way to prove it. We model your plans, identify the most cost-effective path to a 7 star rating and a compliant Whole of Home score, and give you a NatHERS certificate your certifier will accept. Independent, accurate, and on time.
What is a NatHERS assessment for a new home?
NatHERS, the Nationwide House Energy Rating Scheme, is Australia's national system for rating how energy-efficient a home is. For a new build or major renovation, a NatHERS accredited assessor takes your architectural plans and models them in CSIRO-approved software to predict how the finished home will perform, before a single brick is laid.
The assessment produces two results. A thermal star rating out of 10 shows how well the building shell holds comfortable temperatures on its own, through good design, orientation, insulation and glazing. A Whole of Home rating out of 100 then adds the energy used by major fixed appliances such as heating, cooling, hot water and lighting, offset by any rooftop solar. Together they tell you, your designer and your builder how the home will perform and what it will cost to run.
Because the modelling happens at the design stage, a NatHERS assessment is not just a compliance tick. It is a design tool. Small changes to window size, orientation, insulation or appliance selection can be tested before construction, when they cost almost nothing to make, and lock in lower bills and better comfort for the life of the home.
Why your new home needs a NatHERS rating
Since the 2022 update to the National Construction Code, new houses and townhouses must meet a minimum 7 star NatHERS thermal rating plus a Whole of Home score of at least 60 out of 100. New apartments must average 7 stars across all units, with no single unit below 6 stars, and reach a Whole of Home score of at least 50. The jump from the old 6 star minimum is significant: a 7 star home typically needs 20 to 25 percent less energy for heating and cooling.
It is your evidence of compliance
A NatHERS certificate is the document your building surveyor or certifier relies on to confirm energy efficiency compliance when issuing a building permit. For most new homes, construction cannot lawfully begin without it. Getting the assessment right, early, keeps your approval on track.
The requirements are stable
NCC 2025 was published in 2026 with no new residential energy efficiency changes, and further residential changes have been paused, so the 7 star and Whole of Home framework is what the industry will be building to for years. There is no imminent move to 8 stars. That stability makes it worth designing well now rather than to the bare minimum.
What your assessment includes
The star rating (out of 10)
The star rating measures thermal performance, how much heating and cooling your home needs to stay comfortable. It is driven entirely by the building shell: orientation, window size and placement, glazing type, wall, roof and floor insulation, construction materials and shading. A higher star rating means the home stays comfortable with less mechanical heating and cooling, which is where the largest share of household energy goes.
The Whole of Home rating (out of 100)
The Whole of Home rating builds on the star rating by adding the energy used by major fixed appliances, including heating and cooling systems, hot water, lighting, and pool or spa pumps, then subtracting any energy generated by rooftop solar. It rewards efficient electric appliances and solar, and is why two homes with the same star rating can have very different running costs. To comply, a new house needs a Whole of Home score of at least 60.
Your NatHERS certificate
On completion you receive an official NatHERS certificate showing both ratings, the modelled heating and cooling loads, and the climate zone used. This is the document you lodge with your building permit application.
When to involve an assessor, and how it works
The single best time to engage a NatHERS assessor is during design development, not after your plans are finalised. Once construction documents are locked in, fixing a shortfall means redrawing orientation, walls or windows, which is slow and expensive. Brought in early, an assessor can test options on screen and steer the design to comply with little or no extra build cost. Here is how we work:
1. Send your plans.
We start from your floor plans, elevations, sections and window schedule, plus any specifications for insulation, glazing and fixed appliances.
2. We model the design.
Your home is built virtually in accredited NatHERS software for your exact site and climate zone, producing a preliminary star and Whole of Home rating.
3. We find the efficient path to compliance.
If the design falls short, we show you the lowest-cost changes that get you over the line, whether that is glazing, insulation, orientation tweaks or appliance selection.
4. You receive your certificate.
Once the design meets target, we issue your NatHERS certificate ready for permit lodgement.
What influences your star rating
A NatHERS rating is the sum of many design decisions working together. The biggest levers are usually:
Orientation and layout. Living areas facing north capture winter sun and are easier to shade in summer, which lifts the rating at no material cost.
Glazing. Window type, size, placement and shading have a large effect. Double glazing and well-positioned eaves often make the difference.
Insulation. Ceiling, wall and floor insulation levels strongly influence how much heating and cooling the home needs.
Thermal mass. Materials like concrete slabs and brick can stabilise indoor temperatures, particularly in temperate climates.
Sealing. Reducing air leakage keeps conditioned air inside. It is rewarded in the modelling and matters even more in practice.
Climate zone. Australia has many climate zones, and the same design performs differently in each. NatHERS software accounts for your local climate automatically.
For the Whole of Home score, the choice of heating, cooling and hot water systems and the addition of rooftop solar are the decisive factors. Efficient electric systems and solar typically lift the score the most.
Who we work with
We provide NatHERS assessments for new residential projects of every size:
- Builders and project home companies needing reliable, fast certificates across multiple designs and climate zones.
- Architects and building designers who want energy performance designed in from concept, not bolted on at the end.
- Owner-builders navigating the building permit process for the first time.
- Developers delivering townhouses and apartments that must meet Class 2 requirements.
- Renovators undertaking major works or extensions that trigger NatHERS assessment.
Why choose Australian Energy Assessments
We are independent. We don't sell windows, insulation, heat pumps or solar, so our advice is about getting your home compliant and comfortable for the lowest sensible cost, never about steering you toward a product.
We treat the assessment as design help, not paperwork. When a design falls short, we explain the why and the options in plain language, so you keep control of the look, budget and feel of the home while still meeting the code.
And we are reliable on the things that hold up a build: clear turnaround, certificates accepted by certifiers across the country, and assessors who answer the phone when you have a question. Based in Melbourne, working with clients across Australia.
Frequently asked questions
What is a NatHERS assessment for a new home?
It is an energy rating produced by modelling your building plans in CSIRO-approved software before construction. It gives your home a thermal star rating out of 10 and a Whole of Home rating out of 100, and results in a NatHERS certificate used to show compliance with the National Construction Code.
Is a NatHERS rating mandatory for new homes?
For most new houses and townhouses, yes. A NatHERS assessment is the most common way to demonstrate the energy efficiency requirements of the National Construction Code, and a certificate is generally required before a building permit can be issued.
What rating does my new home need to pass?
New houses and townhouses must reach a minimum 7 star thermal rating plus a Whole of Home score of at least 60 out of 100. New apartments must average 7 stars across all units, with no unit below 6 stars, and reach a Whole of Home score of at least 50.
What is the difference between the star rating and the Whole of Home rating?
The star rating out of 10 measures the building shell, how much heating and cooling the home needs based on design, orientation, insulation and glazing. The Whole of Home rating out of 100 adds the energy used by fixed appliances and subtracts rooftop solar, for a fuller picture of running costs.
When should I get a NatHERS assessment during my project?
As early in the design as possible. Modelling the design before plans are finalised lets you test cost-free improvements like orientation and window placement. Once construction documents are locked in, fixing a shortfall is far more expensive.
What happens if my design does not reach 7 stars?
We show you the most cost-effective changes to get there, such as upgrading glazing, adding insulation, adjusting window sizes or improving shading. Caught early, most homes reach compliance with minor design adjustments rather than major cost.
What information does the assessor need?
Floor plans, elevations and sections, a window schedule, and specifications for insulation, glazing and major fixed appliances. The more complete the documentation, the more accurate the rating.
How long does a NatHERS assessment take?
Turnaround depends on the complexity of the design and how complete the plans are. A straightforward house is usually quick. Contact us with your plans and we'll give you a clear timeframe and quote.
What is a NatHERS certificate and why do I need it?
It is the official document showing your star rating, Whole of Home score, heating and cooling loads and climate zone. Your building surveyor or certifier uses it as evidence of energy efficiency compliance, and most new homes cannot start construction without one.
Does NatHERS apply to renovations and extensions?
Major renovations and extensions can trigger a NatHERS assessment, depending on the scope of work and your state or territory rules. If you are altering the building shell significantly, it is worth checking early. We can advise whether your project needs one.
Does NCC 2025 change the requirements?
No. NCC 2025 introduced no new residential energy efficiency measures, and further residential changes have been paused, so the 7 star and Whole of Home framework remains the standard for the foreseeable future. There is no imminent move to 8 stars.
Does NSW use NatHERS?
In NSW, thermal performance is assessed through BASIX rather than NatHERS directly, with targets aligned to the 7 star standard. The compliance pathway differs from other states, but the underlying performance outcome is comparable. We can guide NSW projects through the correct pathway.
How does climate zone affect my rating?
Australia spans many climate zones, and the same design performs differently in each. A home that rates well in a temperate zone may need different glazing or insulation in a hot or cold zone. NatHERS software applies your local climate data automatically.
Do all-electric homes rate better under Whole of Home?
Often, yes. Efficient electric appliances like heat pump hot water and reverse-cycle air conditioning, combined with rooftop solar, tend to lift the Whole of Home score because the rating rewards low running energy and on-site generation.
What software is used for NatHERS assessments?
Accredited tools such as AccuRate, FirstRate5 and BERSPro, all built on the CSIRO Chenath engine. They model your home's thermal performance and Whole of Home energy use to produce a nationally consistent rating.
Can I aim higher than 7 stars?
Yes. Seven stars is a floor, not a ceiling. Many homes are designed to 8 stars or beyond for greater comfort and lower bills, and the extra performance is usually most affordable when planned from the start.
My home passes thermal but fails Whole of Home. What now?
This usually means the building shell is good but the appliances or energy supply need work. Switching to efficient electric heating, cooling or hot water, or adding solar, typically brings the Whole of Home score up to a compliant level.
How much does a NatHERS assessment for a new home cost?
It depends on the size and complexity of the design and the number of dwellings. Single, simple works start from around $300. Send us your plans for a transparent, fixed quote before any work begins.
Building or renovating? Let's get your rating right the first time.
Send us your plans and we'll model your home, find the most cost-effective route to compliance, and issue a NatHERS certificate your certifier will accept. Independent advice, clear turnaround.