Residential Energy Performance
Understand how the thermal and household energy performance of an existing Australian home can now be assessed through the NatHERS for Existing Homes framework, using its current construction, installed systems and onsite energy features.
A practical guide for homeowners, housing providers, lenders, real estate stakeholders and project teams seeking clarity on existing-home ratings, staged rollout, assessment methods and evidence-based pathways for improving residential performance.
Explore Existing Home RatingsIn Brief
A Home Energy Rating provides a structured assessment of the energy performance of a home that has already been built. Under NatHERS for Existing Homes, the framework is now in staged rollout, with Stage 1 released in July 2025 and further expansion planned through Stage 2 in mid-2026.
The assessment combines a thermal performance rating with an assessment of household energy use. This can include the home’s orientation, construction, insulation, glazing and shading, together with installed heating and cooling, hot water, major appliances, onsite solar generation and battery storage.
Information is generally collected through a visit to the property and used to model how the home performs. The resulting rating and guidance can help households understand current comfort and energy-use outcomes, identify areas of weaker performance and make more informed decisions about future upgrades.
The home’s thermal performance and modelled energy use, based on its existing construction, installed systems and onsite energy features.
NatHERS for Existing Homes has moved from national trial work into early implementation, with broader rollout and updated tools planned through Stage 2.
A clearer view of current performance and practical guidance that can inform comfort, efficiency and future home-upgrade decisions.
Knowledge Navigation
Explore how existing homes are assessed, what the rating includes, how the results can be interpreted and where Home Energy Ratings sit within the wider Australian residential energy landscape.
Foundation
Performance
Assessment
Application
Boundaries
Further Guidance
Assessment Scope
A Home Energy Rating combines two complementary measures: the thermal performance of the building and the modelled energy performance of the household systems operating within it.
Thermal Performance
The thermal assessment considers how much heating and cooling the home is predicted to need to remain comfortable. The result is expressed as a thermal star rating out of 10.
The assessment may consider:
Household Energy Performance
The wider energy assessment builds on the thermal result and models the energy used by the home’s major systems and appliances. The result is expressed as a Home Energy Rating out of 100.
The assessment may consider:
Two Linked Measures
A strong thermal rating does not automatically mean every installed system is efficient. In the same way, efficient appliances cannot fully overcome a home that requires substantial heating or cooling. The two results provide different but connected views of performance.
Modelled Performance
The rating uses standard assumptions so that homes can be compared on a consistent basis. Actual household energy use and bills will still vary according to occupancy, personal comfort preferences, appliance use and the way the home is operated.
Existing Home Assessment
A Home Energy Rating examines the performance of an existing dwelling using information about its current construction, installed energy systems and observable condition.
Most Australian homes were built before today’s residential energy-performance expectations were introduced. Their comfort and energy use may be shaped by a combination of original construction, later renovations, ageing materials, replaced appliances and changes that are not fully documented on the available plans.
A Home Energy Rating is intended to create a more consistent picture of how one of these homes performs in its present state. Rather than relying only on drawings or assumptions about what should have been installed, the assessment uses property information and evidence collected from the completed dwelling.
This information is used to model the home’s thermal performance and household energy use. The resulting rating can help explain how the dwelling responds to its climate, where energy is likely to be used and which areas may warrant closer consideration when future improvements are being planned.
Home Energy Rating and NatHERS
Home Energy Rating is the public-facing name being introduced for Australian home energy ratings. For existing dwellings, assessments sit within the expanded Nationwide House Energy Rating Scheme, or NatHERS. The Home Energy Rating name is intended to make the service clearer for households, while NatHERS continues to support the technical framework, assessor requirements, governance and consistency of the ratings.
Certificate Structure
Certificate Format
The updated Home Energy Rating Certificate for existing homes is designed to make performance easier to understand. Rather than presenting a single thermal result in isolation, the newer format brings together building shell performance, appliance energy use, solar generation and practical upgrade guidance in one place. This makes the assessment more useful for homeowners, buyers and advisers looking to understand where performance can improve over time.
The certificate shows an overall star rating and a broader energy score, helping explain both comfort efficiency and total household energy use.
Core building elements such as insulation, glazing, air leakage and construction materials are summarised to show what is influencing thermal performance.
Heating, cooling, hot water, lighting and other appliances are included to give a fuller picture of how the home uses energy beyond the building shell alone.
Practical upgrade suggestions can help homeowners identify where targeted improvements may improve comfort, reduce energy use and support future disclosure requirements.
Assessment Boundaries
Both assessments use residential energy modelling, but they examine different stages of a home’s life and serve different purposes.
Existing Dwelling
A Home Energy Rating assesses a completed dwelling in its current condition. The model is informed by evidence about what has actually been built and which energy systems are installed at the property.
Assessment basis
Existing construction, observable conditions, installed systems, property records and acceptable supporting evidence.
Main purpose
To explain the home’s current thermal and household energy performance and support more informed decisions about future improvements.
Typical timing
After the home has been constructed and occupied, including homes that have been renovated or altered over time.
Proposed Dwelling
A new-home NatHERS assessment models a proposed design before construction. It relies on drawings, specifications and nominated building elements to predict how the completed home should perform.
Assessment basis
Proposed plans, elevations, construction details, glazing selections, insulation levels and other design specifications.
Main purpose
To test and document the predicted thermal performance of the proposed design and support the relevant residential approval or compliance pathway.
Typical timing
During design development and before construction documentation or approval requirements are finalised.
Important Distinction
A Home Energy Rating describes the assessed performance of a dwelling that already exists. It should not be treated as a substitute for a NatHERS certificate, BASIX documentation, Residential DTS assessment, VURB assessment or another approval document required for proposed building work.
Where a renovation, extension or new dwelling requires formal approval, the applicable compliance pathway should be considered separately. The existing-home rating may still provide useful background information, but its purpose and evidence base remain different.
Thermal Performance
The thermal assessment examines how the home’s form, materials and relationship with its climate influence the amount of heating and cooling needed to maintain comfortable indoor conditions.
Every existing home responds differently to seasonal heat, cold, sunlight and air movement. Orientation, window placement, construction materials and insulation can all influence how quickly internal spaces gain or lose heat and how dependent the household may be on mechanical heating and cooling.
NatHERS modelling brings these characteristics together within the local climate zone. It predicts the heating and cooling energy required to maintain standardised comfort conditions and converts that result into a thermal star rating between 0 and 10.
A higher star rating generally indicates that the building fabric provides greater protection from outdoor conditions and requires less heating and cooling to remain comfortable. A lower rating can help reveal where the existing home is more exposed to unwanted heat gain, heat loss or seasonal discomfort.
Building Characteristics
The model considers the interaction between the home’s physical characteristics rather than treating any single material or feature as the sole measure of performance.
The direction rooms and windows face, the arrangement of internal spaces and the home’s exposure to seasonal sunlight.
Existing construction systems, materials, insulation levels and the way different parts of the building envelope transfer heat.
Window size, orientation, glass and frame performance and their contribution to heat gain and heat loss.
Eaves, awnings, external obstructions and other fixed elements that affect the amount of solar heat reaching the home.
Opportunities for useful air movement together with uncontrolled air leakage through gaps and openings.
The weather conditions relevant to the property’s location, including seasonal temperature patterns and solar exposure.
Reading the Result
The thermal star rating describes the performance of the building fabric and its predicted heating and cooling needs. The efficiency of installed heating, cooling, hot water and other energy systems is considered separately within the wider Home Energy Rating.
Household Energy Performance
The wider Home Energy Rating considers the relationship between the building’s thermal performance and the major energy systems already operating within the dwelling.
Two homes with similar thermal performance can still have very different overall energy outcomes. The efficiency and fuel source of heating, cooling, hot water and other major systems can influence the amount of energy the household is predicted to use.
The household energy component builds on the thermal assessment by modelling relevant installed equipment together with standardised assumptions about occupancy and appliance use. Where rooftop solar or battery storage is present, these features can also be included in the overall assessment.
The result provides a consistent way to understand how building fabric, energy systems and onsite generation interact. It can also help distinguish between performance limitations created by the dwelling itself and those associated with the equipment used to heat, cool and service it.
Energy Systems
The assessment considers the relevant systems and energy features present at the property, together with standardised assumptions needed to compare homes consistently.
The type, efficiency and energy source of the systems used to maintain comfortable indoor temperatures.
The installed hot-water system, its efficiency and the energy source used to provide household hot water.
Relevant installed cooking appliances and other fixed energy-using equipment included within the rating method.
Standardised energy allowances and relevant installed loads, including pool or spa equipment where applicable.
Existing solar photovoltaic generation and its contribution to reducing modelled household energy demand.
Installed battery capacity and its modelled relationship with onsite solar generation and household energy use.
Reading the Result
The model uses consistent occupancy and operating assumptions so that homes can be compared on a common basis. Actual energy consumption will still vary with household size, comfort preferences, appliance use, tariffs, weather and day-to-day behaviour.
The result can reveal where energy performance may be improved, but it is not a complete electrification strategy, appliance specification or detailed solar and battery design. Those decisions may require separate technical advice.
Assessment Process
The assessment combines information about the property with an onsite review, accredited energy modelling and a formal Home Energy Rating Certificate.
Step 01
The property, assessment purpose and access requirements are confirmed. Available plans, renovation records, appliance information and other relevant documents may be reviewed before the visit.
Step 02
The dwelling is inspected and measured so its current geometry, construction, glazing, shading and installed energy systems can be recorded using the required assessment process.
Step 03
The collected information is entered into accredited software. The assessor models the home’s thermal performance and household energy use in accordance with the applicable NatHERS requirements.
Step 04
Once the assessment is finalised, the accredited assessor issues a Home Energy Rating Certificate showing the relevant rating outcomes and modelled performance information.
At the Property
Existing homes frequently differ from their original drawings. Renovations, replaced windows, added insulation, extensions and changed energy systems can all affect performance, even where those changes are not fully documented.
The onsite assessment helps establish which features are present at the time of rating. Observations and measurements are supported by available documentation and other acceptable evidence where required.
After the Visit
The site visit does not produce a rating on its own. The information collected must be translated into a consistent digital model of the dwelling and assessed using the relevant climate data, technical rules and standard operating assumptions.
This modelling stage allows homes to be assessed on a comparable basis rather than relying only on occupant impressions, historical energy bills or a visual inspection of individual features.
Accredited Assessment
Accredited assessors are required to follow the applicable technical guidance, evidence requirements, quality-assurance processes and professional obligations. A valid Home Energy Rating Certificate includes a QR code linking to its digital record.
Existing Building Evidence
Existing homes are not always fully documented. The assessment therefore brings together onsite observations, measurements, records and acceptable supporting evidence to represent the dwelling as reliably as possible.
A completed dwelling may differ substantially from its original drawings. Extensions may have been added, windows replaced, rooms reconfigured or energy systems upgraded without every change appearing in the available documentation.
During the property visit, the assessor records the geometry and orientation of the home together with relevant construction, glazing, shading and installed equipment. Measurements, photographs, labels and property records may all contribute to the assessment evidence.
The objective is not to assume that every feature matches the original specification. It is to establish a defensible representation of the home in its assessed condition, using the best information that can reasonably be confirmed.
Property Review
The required information depends on the property, but the review generally covers the building geometry, envelope and relevant household energy systems.
Floor layout, dimensions, ceiling heights, room use, orientation and the relationship between the home and its site.
Observable roof, wall and floor systems together with available evidence about insulation and other concealed elements.
Window dimensions, frame and glazing information, orientation, eaves, awnings and relevant external obstructions.
The type, location, capacity and available efficiency information for installed conditioning systems.
Relevant hot-water, cooking and fixed equipment details required for the household energy assessment.
Available information about rooftop solar, system capacity, orientation and installed battery storage.
Concealed Construction
Insulation and construction layers may sit behind finished surfaces or within inaccessible spaces. Where a feature cannot be verified directly, the assessor must apply the relevant evidence and modelling requirements rather than treating an unconfirmed improvement as present.
Assessment Scope
A Home Energy Rating does not replace a structural inspection, defect report, electrical inspection, pest assessment or detailed building-condition survey. Separate specialist advice may be required where those matters are relevant.
Market Readiness
Certified Energy and Cotality are collaborating to explore and refine practical, scalable and quality-assured delivery models for the voluntary phase of NatHERS for Existing Homes.
The wider purpose of the collaboration is to help ensure that reliable information about the energy performance of existing homes can be delivered efficiently and used with confidence as the Australian market develops. Achieving this at scale requires more than a rating methodology alone. It also requires workable assessment processes, appropriate use of property data, a capable accredited workforce and consistent technical quality assurance.
Cotality contributes property-data infrastructure, workflow experience and connections across the wider property sector. Certified Energy contributes an experienced assessor workforce and technical expertise in NatHERS and existing-home energy assessment.
Certified Energy’s accredited assessors visit participating homes, collect evidence about the dwelling as it currently exists and complete the required assessment and modelling process. The collaboration is testing how this onsite technical work can be supported by more efficient data and operational workflows without weakening the integrity of the rating.
The goal is to help build a delivery model in which existing-home energy ratings can become more accessible and scalable while remaining grounded in accredited assessment of the actual dwelling.
This is a non-exclusive collaboration focused on testing market readiness and delivery models for the voluntary phase. It does not assume or guarantee any particular future policy pathway.
Using the Assessment
A Home Energy Rating can help identify where the dwelling is losing comfort, using energy inefficiently or receiving limited benefit from its installed systems.
Existing homes rarely have one isolated performance problem. Discomfort may be influenced by a combination of limited insulation, poorly performing windows, uncontrolled air leakage, solar exposure and inefficient heating or cooling equipment.
The rating helps separate the thermal performance of the building from the energy performance of the systems operating within it. This can provide a more useful starting point than selecting products before the underlying source of the problem has been understood.
The results can support conversations with designers, builders, tradespeople and energy specialists. They may also help households consider which improvements are likely to deliver comfort benefits, reduce modelled energy demand or prepare the home for later stages of work.
Upgrade Areas
The relevant opportunities will depend on the home, its climate and the way different parts of the building and energy system interact.
Sealing uncontrolled gaps around doors, windows and penetrations may help reduce unwanted heat loss, heat gain and local discomfort.
Roof, ceiling, wall and floor performance may be reviewed where insulation is limited, inconsistent, damaged or absent.
Window coverings, external shading, glazing improvements or targeted window replacement may be considered in response to specific heat-gain or heat-loss issues.
Older or inefficient equipment may warrant review, particularly after practical opportunities to reduce the home’s underlying heating and cooling demand have been considered.
Replacement cycles can provide opportunities to consider more efficient equipment, suitable fuel choices and the home’s available electrical capacity.
Rooftop solar and battery storage may improve the modelled net-energy position, but system sizing and suitability require separate site-specific analysis.
Upgrade Sequencing
Not every home needs a complete renovation. The rating can help organise smaller actions, planned replacements and larger building work within a more coherent performance pathway.
Stage 01
Review seasonal operation, shading, ventilation and other low-cost ways of using the existing home more effectively.
Stage 02
Address practical fabric issues, draughts, shading or selected systems where the assessment indicates a clear opportunity.
Stage 03
Use normal equipment replacement cycles to consider more efficient heating, cooling, hot-water and cooking systems.
Stage 04
Coordinate larger envelope, glazing or services upgrades with planned renovations where access and construction sequencing make them more feasible.
Scope Boundary
Suggested opportunities should be tested against the home’s construction, climate, budget, condition and planned use. Structural changes, moisture management, electrical upgrades, heritage considerations and product suitability may require advice from appropriately qualified specialists.
A Home Energy Rating is therefore best understood as an evidence base for further decisions rather than a complete retrofit specification or guarantee of a particular energy-saving outcome.
NSW Program Context
The NSW Home Energy Saver loan guidelines include a NatHERS assessment and certificate for an existing home among the eligible energy-saving activities.
The assessment is optional rather than a compulsory part of every loan application. For households considering several possible improvements, it may help clarify the home’s thermal performance, broader energy use and the upgrades that deserve closer investigation.
Loan eligibility and access to an assessment remain subject to the participating finance provider’s lending requirements and approved-supplier arrangements.
Read about NatHERS assessments and the NSW Home Energy Saver loan
2026 Trial Outcomes
The 2026 NatHERS for Existing Homes Trial Outcomes Report confirms that the national existing-homes rating model has moved beyond trial testing and into staged rollout. Stage 1 commenced in July 2025, with Stage 2 planned for mid-2026 to broaden access, improve tools and support wider assessor accreditation.
The trial found that existing-home assessments can be delivered in real-world conditions and that the model is fit for broader rollout, while still requiring continued refinement as it scales.
The next phase focuses on improving assessment tools, training, quality assurance and digital workflows so ratings become more consistent, scalable and easier to integrate into market processes.
As the scheme expands, Home Energy Ratings are expected to support clearer energy performance disclosure, more informed upgrade decisions and stronger visibility of existing-home performance.
Read our summary of the 2026 trial outcomes and what they mean for homeowners, assessors, property professionals and the broader residential energy market.
Read the 2026 NatHERS Existing Homes Trial summary →Rating Applications
A consistent rating can help different people understand the energy performance of an existing dwelling, whether the focus is home improvement, property information, finance or the management of a larger housing portfolio.
Households
Homeowners can use the rating to better understand comfort, thermal demand, major energy uses and the areas that may warrant further investigation before upgrades are planned.
Property Decisions
Where a rating is shared during sale or lease, prospective occupants can compare the assessed energy performance of homes and identify potential comfort or upgrade considerations.
Finance
Banks and other finance providers may use recognised ratings to support eligible green-finance products, verify performance or help structure lending for home improvements.
Housing Portfolios
Housing providers and program managers can use a consistent assessment method to understand performance patterns, identify priorities and support staged investment across multiple dwellings.
Individual Homes
Without a structured assessment, households may rely on energy bills, occupant experience or isolated product advice when trying to understand how a home performs. Each can provide useful information, but none creates a complete and consistent picture on its own.
A Home Energy Rating combines the dwelling’s building fabric, major energy systems and onsite generation within one modelled assessment. This allows current performance to be discussed using a recognised method rather than relying only on impressions or assumptions.
The result may help a household decide whether further investigation is needed, communicate performance information to other parties or establish a baseline before improvement work begins.
Portfolio and Program Delivery
Larger rating programs require additional planning so that property data, assessment methods and outputs remain consistent across different dwelling types and locations.
Dwelling types, locations, access requirements and program objectives may be reviewed before assessments are scheduled.
Clear field processes help ensure that equivalent information is recorded across properties and can be used reliably in later modelling.
Assessment evidence, modelling decisions and certificate outputs may require coordinated review across the delivery team.
Aggregated results can help identify recurring performance issues, common dwelling archetypes and opportunities for staged investment.
Scope Boundary
A standard Home Energy Rating provides a consistent assessment of the dwelling, but a finance product, government program, property transaction or portfolio initiative may impose separate rules about assessor eligibility, evidence, certificate age, reporting format or quality assurance. These requirements should be confirmed for the intended use before the assessment is commissioned.
Disclosure and Industry Development
Home Energy Ratings are part of a wider Australian effort to make the comfort, energy performance and upgrade potential of existing homes easier to understand and compare.
Australian property information has traditionally provided limited visibility into the energy performance of existing homes. Buyers and renters may be able to compare location, size, condition and price without receiving equivalent information about predicted comfort, heating and cooling demand or household energy performance.
A recognised Home Energy Rating creates a more consistent way to describe these characteristics. It can provide households and property-market participants with information that is based on an accredited assessment rather than general sustainability claims or isolated product features.
This common rating language may support future disclosure schemes, voluntary property information, finance products, housing programs and broader efforts to improve the performance of Australia’s existing housing stock.
Disclosure Framework
Disclosure is intended to make recognised energy-performance information available when households are making significant property decisions.
A common certificate and rating method can help people compare homes using information prepared on a consistent basis.
Buyers and renters may gain greater visibility into predicted comfort, energy demand and possible areas for future improvement.
Owners who have improved their homes may have a clearer way to communicate assessed performance to the property market.
Consistent ratings may support new finance, valuation, retrofit and portfolio-management pathways as the market develops.
Developing System
Existing-home assessment methods, software, assessor capacity, certificates and possible disclosure applications have been developed and tested progressively rather than introduced as one immediate nationwide requirement.
Assessment Method
A national method supports greater consistency in how existing construction, installed systems and onsite energy features are assessed.
Assessor Capacity
Accredited assessors require specific existing-homes training so property data, evidence and modelling decisions are handled appropriately.
Market Testing
Trials have helped test household participation, onsite assessment, software, certificates and the use of ratings within property transactions. Certified Energy’s participation in the NSW Real Estate Agent Trial also highlighted the importance of consumer understanding, practical delivery and a clear pathway from assessment to action. Read what the NSW Real Estate Agent Trial revealed.
Government Adoption
Any formal disclosure scheme would be implemented through the relevant government and may include its own timing, exemptions and transaction rules.
Voluntary Use
A household, housing provider, lender or property professional may choose to obtain or use a rating even where no sale-or-lease disclosure requirement applies. Its suitability should be considered against the intended purpose.
Legal Requirements
A Home Energy Rating should not automatically be treated as satisfying a jurisdiction-specific disclosure obligation. Existing legal schemes, including the ACT EER pathway, may use separate assessment, certificate and practitioner requirements.
Residential Energy Pathways
Home Energy Rating is designed for a dwelling that has already been built. Other residential energy pathways assess proposed designs, approval requirements or specified systems before construction or alteration work is completed.
Existing Dwelling
Assesses the current thermal and household energy performance of a completed home using onsite evidence, installed systems and accredited modelling.
Current condition and existing performance
Proposed Design
Models the predicted thermal performance of a proposed new home from plans, construction details, glazing selections and design specifications.
Explore NatHERSProposed Energy Systems
Assesses the specified energy systems, appliances, solar generation and storage of a proposed new home alongside its NatHERS thermal result.
Explore Whole of HomeApproval and Compliance
These pathways address applicable approval or compliance requirements for proposed residential building work rather than rating an existing home in its current condition.
Explore residential complianceDifferent Assessment Stages
A proposed home can be adjusted before it is built. Its orientation, glazing, insulation, shading and energy systems can be tested against the design documentation and revised as the project develops.
An existing home requires a different evidence base. The assessor must establish what is present at the property, how the dwelling has changed over time and which installed systems form part of its current energy performance.
The modelling tools and energy concepts may be related, but the assessment purpose, timing and documentation should not be treated as interchangeable.
Choosing the Appropriate Pathway
The same property may be discussed in several energy contexts, but each pathway should retain a clear role.
Use Home Energy Rating where the purpose is to understand the energy performance of a dwelling that is already built.
Use new-home NatHERS and the relevant Whole of Home requirements where a dwelling is being designed before construction.
Use the applicable BASIX, NatHERS, DTS, VURB or other jurisdictional pathway for proposed building work requiring formal approval.
Check whether a separate state or territory disclosure scheme applies when a rating is intended for the sale or lease of a property.
Core Boundary
The rating may provide valuable context for renovation planning or future property decisions, but any proposed building work should still be assessed against the planning, building and energy requirements that apply to that project.
Jurisdictional Disclosure
Both pathways assess residential energy performance, but they operate under different rules and should not be treated as interchangeable certificates.
National Assessment
A Home Energy Rating assesses the current thermal and household energy performance of an existing dwelling within the expanded NatHERS framework.
Assessment scope
Existing building fabric, thermal performance, installed energy systems, onsite generation and storage.
Typical use
Household understanding, upgrade planning, voluntary property information, finance and housing programs.
ACT legal status
It is not currently a substitute for the EER Statement required under the legislated ACT disclosure pathway.
ACT Disclosure Document
The ACT Energy Efficiency Rating Disclosure Scheme is a separate, legislated pathway used to disclose the energy performance of applicable residential property being sold in the ACT.
Assessment scope
Energy performance assessed in accordance with the current ACT House Energy Rating Scheme requirements.
Practitioner requirements
The statement must be prepared through the ACT pathway by a practitioner holding the required authorisation.
Certificate requirements
The scheme uses its own recognised software, assessment process, statement format and submission requirements.
Why the Boundary Matters
Both assessments may use energy modelling and both can express aspects of residential thermal performance. That similarity can make the pathways appear interchangeable, particularly where an existing home already has a recent energy rating.
The legal purpose of the document remains important. An assessment intended to help a household understand and improve its home is not automatically valid for a regulated property transaction.
Where an energy rating is required for the sale of an ACT property, the assessment should be commissioned specifically through the ACT EER pathway. This allows the correct practitioner, methodology, statement and submission process to be used from the beginning.
Three Different Layers
These related concepts operate at different levels and should remain clearly separated.
Assessment
A national method for assessing the current thermal and household energy performance of an existing home.
Policy Framework
A nationally agreed model that governments may use when developing future disclosure arrangements at sale or lease.
Legislated Scheme
An existing ACT legal pathway with its own requirements for applicable property transactions, practitioners and statements.
Current Boundary
The ACT may consider future alignment with the national Home Energy Rating system, but under the current arrangements the pathways remain separate. The requirements applying at the time of the property transaction should always be confirmed before an assessment is ordered.
Program Transition
The Residential Efficiency Scorecard helped establish a practical way to assess the energy use, comfort and improvement potential of existing Australian homes. Home Energy Rating now carries that work into a broader national framework.
Introduced in 2017, the Residential Efficiency Scorecard provided households with a structured assessment of an existing home. It considered the building fabric, major fixed appliances and seasonal comfort, then provided a rating and tailored suggestions for improving performance.
The program also helped build practical experience in onsite data collection, assessor training, household communication and the delivery of upgrade guidance. These lessons contributed to the development of the expanded national approach for rating existing homes.
The transition does not mean the earlier program had the same certificate, methodology or rating outputs as Home Energy Rating. Scorecard should be understood as an important predecessor rather than another name for the current assessment pathway.
Understanding the Transition
The practical goal remains familiar, but the national framework, assessment method and certificate structure have developed further.
Shared Purpose
Both pathways help households understand current energy performance, seasonal comfort and possible areas for improvement.
Broader Alignment
Home Energy Rating brings existing-home assessments into closer alignment with the national system already used for new homes.
Expanded Results
The current pathway distinguishes the thermal star rating from the wider Home Energy Rating covering household systems and onsite energy.
Current Certificate
A Residential Efficiency Scorecard report should not be presented as though it were a current Home Energy Rating Certificate.
Existing Scorecard Reports
A previous Scorecard report may help explain the assessed condition of a home at that time and record earlier upgrade recommendations. Its findings should be considered alongside any renovations, appliance changes or deterioration that occurred after the assessment.
Current Evidence
Where a lender, housing program, property process or homeowner requires an assessment of present performance, confirm which certificate and assessment pathway is accepted before relying on an older Scorecard report.
Legacy Guidance
Certified Energy retains separate legacy guidance explaining how the Residential Efficiency Scorecard worked, what its reports contained and how it relates to the current Home Energy Rating pathway.
View Residential Efficiency Scorecard legacy guidance
Assessment Preparation
The assessor collects the essential property information during the site visit, but clear access and any reliable records already available can make the assessment more efficient and reduce uncertainty.
Existing homes are often assessed without a complete set of drawings or specifications. Original plans may have been lost, renovations may not be fully documented and some construction details may be concealed behind finished surfaces.
These gaps do not automatically prevent an assessment. The property visit allows the assessor to measure the dwelling, record visible building elements and collect information about the energy systems currently installed.
Where supporting documents are available, they can help explain changes to the home and provide evidence for features that are difficult to verify visually. Information should reflect the dwelling in its present condition rather than only its original design.
Helpful Preparation
Not every item is required for every home. Available information is reviewed alongside the assessor’s onsite observations.
Arrange access to internal rooms, external walls and relevant heating, cooling, hot-water, solar and battery equipment.
Locate any available drawings, renovation documentation, invoices, installation records or photographs of completed work.
Make model numbers or labels accessible for relevant heating, cooling, hot-water and fixed energy systems.
Identify extensions, added insulation, replaced windows, new appliances and other changes made since the home was built.
Missing Information
Where details cannot be observed or supported by acceptable evidence, the assessor applies the relevant assessment rules rather than assuming an unverified material, insulation level or equipment specification is present.
Frequently Asked Questions
The Home Energy Rating Certificate for existing homes is evolving as NatHERS expands into broader market rollout. Newer certificate formats are designed to make building performance easier to understand by combining thermal performance, appliance energy use and upgrade guidance into a single homeowner-facing report.
A Home Energy Rating is an accredited assessment of a dwelling that has already been built. It considers the home’s current construction, thermal performance, installed energy systems and onsite energy features rather than assessing a proposed design from plans alone. Read the short guide to Home Energy Ratings.
Home Energy Rating is the clearer public-facing name for the existing-home assessment pathway operating within the expanded NatHERS framework. NatHERS continues to provide the technical rules, accredited software, assessor requirements and quality-assurance framework behind the rating.
A new-home NatHERS assessment models a proposed dwelling from architectural plans, construction details and specifications before it is built. A Home Energy Rating assesses a completed dwelling using onsite observations, measurements, installed systems and evidence about the home’s current condition. Compare existing-home and new-home assessments.
Yes. The assessment relies on information collected from the completed dwelling. The assessor generally records the home’s geometry, construction, glazing, shading and relevant installed energy systems during an onsite visit.
In many cases, yes. Existing homes can often be measured during the property visit. Plans, renovation records, product information and installation documents may still be useful where they help verify concealed construction or changes made to the dwelling. Read more about ratings without original plans.
The certificate includes a thermal star rating out of 10, which describes the home’s modelled heating and cooling demand, and a Home Energy Rating out of 100, which also considers major household energy systems, onsite solar generation and battery storage. Supporting information may also describe predicted comfort, energy use, emissions and the contribution of different energy categories.
Not exactly. The rating uses standardised assumptions so that different homes can be compared consistently. Actual energy consumption and costs will vary with household size, personal comfort preferences, appliance use, energy tariffs, weather and day-to-day behaviour.
The assessment can help identify areas of weaker thermal or household energy performance and provide guidance about possible improvements. These may relate to draught sealing, insulation, glazing, shading, heating and cooling, hot water, appliances, solar or battery storage. The rating does not replace detailed retrofit design, electrical advice, structural assessment or product specification. Learn how upgrade guidance may be included.
A national disclosure framework has been developed, but this does not mean that Home Energy Rating disclosure is already mandatory for every property sale or lease in Australia. State and territory requirements should be checked for the property location and transaction. Learn more about mandatory rating requirements.
No. The ACT Energy Efficiency Rating Disclosure Scheme is a separate legislated pathway with its own assessment, practitioner, software and certificate requirements. A standard Home Energy Rating should not be treated as an ACT EER Statement.
No. Home Energy Rating assesses a dwelling in its existing condition. Proposed new homes, alterations and additions may require separate NatHERS, BASIX, Residential DTS, VURB or other approval documentation depending on the project and jurisdiction.
No. The Residential Efficiency Scorecard was a separate existing-home assessment program that closed on 23 June 2026. Home Energy Rating now operates through the expanded NatHERS framework and uses a different methodology, rating structure and certificate. View the Residential Efficiency Scorecard Legacy Guide.
The timeframe depends on the size and complexity of the dwelling, its location, available documentation and the amount of evidence requiring review. The complete process includes preparation, the property visit, energy modelling, quality checks and certificate production. Read more about assessment timeframes.
Cost may vary with dwelling size, complexity, location, travel, access, documentation and the intended use of the certificate. Portfolio assessments, program delivery and additional reporting requirements may need a separately defined scope. Read more about Home Energy Rating costs.
The certificate records the dwelling in its assessed condition. Renovations, new glazing, insulation changes, replacement energy systems, solar installation or battery storage may affect how accurately an earlier certificate represents the home. A lender, government program or property process may also impose its own certificate-age requirements.
Yes. Portfolio and program delivery may involve coordinated property triage, consistent onsite data collection, accredited modelling, quality assurance and structured reporting across multiple dwellings. The delivery model should be scoped around the portfolio, intended outputs and any program-specific requirements. Read more about Home Energy Ratings for housing portfolios.
The current NSW Home Energy Saver guidelines list a NatHERS assessment and certificate for an existing home among the eligible activities. The assessment is optional and is not required for every loan application.
Access remains subject to household eligibility, loan approval and the participating finance provider’s approved-supplier arrangements. Learn how the current program pathway works.
Related Knowledge
Explore focused guidance on assessment methods, existing-home evidence, upgrade decisions and the delivery of Home Energy Ratings across individual dwellings and larger housing portfolios.
Foundation
A concise introduction to how existing Australian homes are assessed and what the resulting rating is intended to explain.
Read the short guide
Comparison
Understand the difference between assessing a completed dwelling and modelling a proposed new-home design for compliance.
Compare the pathways
Site Assessment
Explore the building fabric, windows, shading, installed systems and supporting evidence considered during an existing-home assessment.
Explore the site review
Documentation
Learn how site measurements, property records, photographs and other evidence can help when original drawings are incomplete or unavailable.
Review the evidence options
Assessment Delivery
Examine the real-world challenge of collecting reliable information and delivering consistent ratings across varied and occupied homes.
Read about practical delivery
Portfolio Delivery
See how consistent ratings can support property triage, quality assurance and staged performance planning across multiple dwellings.
Explore portfolio applications
Industry Context
Certified Energy completed more than 500 rating assessments across the national NatHERS for Existing Homes CORE and Scale Stream trials, testing both end-to-end assessments and scaled data-collection workflows. We also participated in the separate NSW Real Estate Agent Trial and contributed formal industry feedback on assessment delivery, evidence quality, training and future accreditation pathways. This practical experience informs how we approach individual homes, portfolio delivery and the quality assurance required for consistent ratings at scale.
Read our analysis of the NSW Real Estate Agent Trial outcomes →
Existing Home Assessment
A Home Energy Rating can provide a clearer picture of the dwelling’s current thermal performance, household energy use and installed energy systems before upgrades or wider property decisions are made.
Send the available property information, plans or renovation records for an initial review. Certified Energy can help confirm whether a Home Energy Rating is the appropriate pathway and identify any separate program, finance or jurisdictional requirements that may apply.
Last reviewed: June 2026. This page is maintained by Certified Energy as part of its Residential Performance Knowledge Hub.
