Comparison Guide

Existing Home Energy Rating vs BASIX

An existing home energy rating and BASIX both relate to residential sustainability, but they are not the same pathway.

BASIX is a NSW planning and compliance pathway used for eligible residential development. An existing home energy rating is used to understand how an already-built dwelling performs for comfort, energy use and upgrade potential.

The difference matters because homeowners, designers, builders and property professionals can easily confuse these terms when working on renovations, alterations, sale preparation or upgrade planning.

Why this comparison matters

In NSW, BASIX is one of the most familiar residential sustainability pathways. Because of that, many people use the word BASIX when they simply mean energy efficiency, sustainability or home performance.

That creates confusion. A homeowner with an existing dwelling may not need BASIX at all. They may need a rating or assessment that explains how their current home performs and what could improve it.

On the other hand, a new residential development or qualifying alteration in NSW may need BASIX documentation even if the owner is not asking for an existing home energy rating.

What is an existing home energy rating?

An existing home energy rating assesses a dwelling that has already been built. It helps explain how the home performs for energy efficiency, comfort and likely upgrade potential.

The assessment may consider the building fabric, insulation, glazing, shading, heating and cooling systems, hot water, solar, batteries and comfort issues. It can help homeowners understand what is driving energy use and what improvements may be worth considering.

For a broader explanation, see What Is a Home Energy Rating for Existing Homes?

What is BASIX?

BASIX stands for the Building Sustainability Index. It is a NSW sustainability pathway used in the planning and approval process for eligible residential development.

BASIX addresses sustainability requirements such as water, energy and thermal performance for NSW residential projects. It is commonly associated with new homes, alterations, additions and certain pools or spas that trigger BASIX requirements.

For NSW project support, see BASIX Certificate NSW.

The core difference: current performance vs approval compliance

The simplest distinction is this: an existing home energy rating looks at how a home performs now. BASIX helps demonstrate how an eligible NSW residential project meets sustainability requirements for approval.

An existing home energy rating is usually concerned with current comfort, energy use, installed systems and upgrade potential. BASIX is concerned with whether a project meets the relevant NSW requirements for water, energy and thermal performance.

This means the two services answer different questions, even when they both involve residential energy performance.

When might you need an existing home energy rating?

An existing home energy rating may be useful when the main question is about the performance of a dwelling that has already been built.

This may include:

• understanding why a home is hot, cold or draughty
• planning energy upgrades
• reviewing insulation, windows or shading
• preparing for electrification
• deciding whether to install solar or batteries
• planning a staged retrofit
• preparing for sale or lease disclosure
• reviewing a residential property portfolio
• understanding a home before renovation decisions are made

For practical preparation, see What Information Do You Need for a Home Energy Rating?

When might you need BASIX?

BASIX is usually relevant when a NSW residential project needs approval documentation and the project falls within the BASIX requirements.

This may include:

• new houses in NSW
• new townhouses or villas
• new apartments or multi-unit residential projects
• eligible alterations and additions
• renovations that trigger BASIX requirements
• certain swimming pools or spas
• development applications requiring a BASIX certificate

BASIX is therefore tied to the NSW approval pathway. It is not simply a general existing-home energy rating.

Can a renovation need both?

Yes. A renovation or alteration project in NSW may involve both types of thinking, depending on the scope and purpose.

If the renovation triggers BASIX requirements, BASIX may be needed for planning or approval. At the same time, the homeowner or design team may want an existing home energy rating to understand how the current dwelling performs before upgrade decisions are finalised.

In that situation, BASIX supports compliance for the proposed project, while the existing home rating supports better decision-making about the current home.

BASIX does not replace an existing home energy rating

BASIX should not be used as a substitute for an existing home energy rating. It is not designed to provide a full performance rating of an established home as it currently operates.

A BASIX certificate may support a development application or approval process. An existing home energy rating may support comfort upgrades, retrofit planning, disclosure readiness or a better understanding of how the current dwelling performs.

The documents may both be useful, but they are not interchangeable.

An existing home energy rating does not replace BASIX

The reverse is also true. An existing home energy rating should not be treated as a BASIX certificate where BASIX is required for a NSW development approval pathway.

If a project needs BASIX, the project team must prepare the correct BASIX documentation. A home energy rating may help the owner understand the existing dwelling, but it does not automatically satisfy BASIX requirements.

This is why the correct pathway should be confirmed early.

How does NatHERS Existing Homes fit in?

NatHERS Existing Homes is part of the broader national shift toward rating established dwellings. It is different from BASIX because it is not simply a NSW development approval document.

The NatHERS Existing Homes pathway is focused on assessing the energy performance of homes that have already been built. This may support homeowners, buyers, sellers, landlords and project teams as existing-home ratings become more common.

For more context, see What Is NatHERS Existing Homes?

Where new-home NatHERS sits beside BASIX

In NSW, new residential projects may involve both BASIX and NatHERS, depending on the project type and approval pathway.

This can create another layer of confusion. New-home NatHERS assesses a proposed design, while NatHERS Existing Homes assesses a dwelling that has already been built. BASIX is a NSW approval pathway that may use or interact with energy assessment inputs depending on the project.

For that distinction, see NatHERS Existing Homes vs New Home NatHERS Assessments.

Which pathway do you need?

The right pathway depends on the project question.

You may need an existing home energy rating if the question is:

• How does this existing home perform now?
• Why is the home uncomfortable?
• Which upgrades should be considered first?
• How can the dwelling be improved before renovation, sale or lease?

You may need BASIX if the question is:

• Does this NSW residential project need sustainability compliance documentation?
• Is this new home, alteration, addition, pool or spa subject to BASIX?
• What documentation is required for the development application or approval pathway?

When in doubt, the project scope and location should be reviewed before selecting the pathway.

Practical implications

For homeowners, the distinction helps prevent requesting the wrong service. A person trying to improve an established home may need performance advice, not BASIX.

For designers and builders, the distinction matters because BASIX may be required for approval, while existing-home rating may support better renovation or retrofit decisions.

For property professionals, the distinction becomes more important as existing home rating disclosure pathways develop separately from new-build planning compliance.

For consultants, the key is to clarify the project scope before recommending BASIX, NatHERS Existing Homes or another assessment pathway.

FAQs

Is an existing home energy rating the same as BASIX?

No. An existing home energy rating assesses the performance of a dwelling that has already been built. BASIX is a NSW planning and sustainability pathway used for new residential development and certain alterations, additions, pools and spas.

When do you need BASIX?

BASIX is generally relevant to NSW residential development applications, including new homes and certain renovation, alteration, addition, pool or spa projects. The exact requirement depends on the project type and approval pathway.

When do you need an existing home energy rating?

An existing home energy rating may be useful when assessing the current performance of an established dwelling, planning upgrades, preparing for future disclosure, reviewing comfort issues or understanding energy efficiency before renovation decisions.

Can BASIX be used as an existing home energy rating?

No. BASIX is not a general rating of an existing home as it currently performs. It is a NSW compliance pathway connected to development approval and sustainability requirements for eligible residential projects.

Can a renovation need both BASIX and an existing home energy rating?

Yes. A renovation or alteration project in NSW may need BASIX for approval while also benefiting from an existing home energy rating to understand the current performance of the dwelling and guide upgrade decisions.

Does BASIX replace NatHERS Existing Homes?

No. BASIX and NatHERS Existing Homes serve different purposes. BASIX relates to NSW development compliance, while NatHERS Existing Homes is an emerging pathway for rating the performance of dwellings that already exist.

Pathway Review

Unsure whether you need BASIX or an existing home rating?

Certified Energy can help clarify whether your project needs BASIX documentation, an existing home energy rating, or another residential assessment pathway.

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Home Energy Rating Timing

How Long Does a Home Energy Rating Take?

The time required for a home energy rating depends on the property, the available information and the assessment pathway.

A straightforward existing home with clear access, available documents and simple systems may be faster to review than a larger home with multiple renovations, missing plans, complex systems or uncertain construction details.

The process usually involves more than one step: initial property review, information gathering, site data collection, modelling or rating input, assessor review, follow-up questions and reporting.

Why timing varies between homes

Existing homes are rarely identical from an assessment perspective. Two houses may look similar from the street but have very different construction, insulation, renovations, system upgrades, access conditions and documentation.

A home with clear plans, easy access and simple building systems may move through the review process more easily. A home with missing plans, several extensions, hidden insulation details or complex services may require more time for data collection and clarification.

This is why it is better to think of the rating as a process rather than a single appointment.

Stage 1: Initial property review

The first timing factor is the initial review. Before an assessor can confirm the likely pathway, they need to understand the property and why the rating is being requested.

Useful starting details include:

• property address
• dwelling type
• approximate age of the home
• number of storeys
• whether plans or photos are available
• reason for requesting the rating
• preferred timing or access constraints

Providing this information early can help Certified Energy review whether the NatHERS Existing Homes assessment pathway is likely to be suitable.

Stage 2: Information gathering

Before the assessment can proceed efficiently, it helps to gather any information already available for the home. This does not need to be perfect, but it should give the assessor a clearer starting point.

Helpful information may include:

• available floor plans or drawings
• renovation or extension history
• photos of the home
• known insulation information
• heating and cooling system details
• hot water system details
• solar PV or battery information
• known comfort issues

For a full checklist, see What Information Do You Need for a Home Energy Rating?

Stage 3: Site data collection

For many existing home assessments, site data collection is an important part of the process. NatHERS has described existing home ratings as requiring assessors to enter homes, collect on-site data, input the data into an energy rating tool and generate a Home Energy Rating Certificate.

Site data collection may include reviewing:

• dwelling layout
• orientation
• windows and glazing
• shading
• visible construction details
• insulation information where available
• heating and cooling systems
• hot water systems
• solar PV and batteries
• comfort or performance issues

The time required for this stage depends on the size, layout and complexity of the home, as well as access to relevant areas.

Stage 4: Assessment input and modelling

After the information has been collected, it needs to be entered into the relevant assessment pathway. This is where property information becomes structured enough to support modelling and rating.

This stage may take longer if there are missing plans, unclear construction details, uncertain insulation, complex renovation history or system information that needs to be checked.

For a fuller process explanation, see How Does a NatHERS Existing Home Assessment Work?

Stage 5: Review and clarification

Existing home assessments often require some review after the first round of information is collected. The assessor may need to clarify details about renovations, insulation, window changes, systems or access limitations.

Follow-up questions can add time, but they can also improve the quality of the assessment by reducing uncertainty where possible.

This stage is especially important for homes without original plans or homes that have been altered over time.

Stage 6: Rating and reporting

After the home’s energy performance is assessed, the final output may include a Home Energy Rating Certificate and supporting information that helps guide decisions about comfort, running costs, emissions and upgrades.

NatHERS explains that Whole of Home can complement the thermal star rating and includes major energy use and generation within the home, such as hot water, heating and cooling systems, pool and spa equipment, lighting, plug-in appliances, solar energy and battery storage.

Reporting time depends on the assessment pathway, review requirements and whether additional clarification is needed before the rating is finalised.

What can delay a home energy rating?

Most delays come from missing or uncertain information, access difficulties or properties that are more complex than expected.

Common timing issues include:

• no available plans
• unclear renovation history
• uncertain insulation details
• large or complex dwellings
• multiple additions or extensions
• limited access to rooms or relevant areas
• missing system information
• unclear solar or battery details
• follow-up questions after review

If original plans are not available, see Can You Get a Home Energy Rating Without Original Plans?

How to help the process move more smoothly

You can help the process by preparing the information that is already available before requesting a quote.

Helpful preparation includes:

• sending the property address
• providing available plans or floor plans
• including photos of the home
• summarising renovation history
• noting known insulation details
• providing heating and cooling system information
• providing hot water system information
• including solar or battery details
• explaining known comfort issues
• confirming access availability

This does not mean you need to solve every information gap yourself. It simply gives the assessor a clearer starting point.

When should you request a home energy rating?

It is best to request a rating before major decisions are locked in. Waiting until after upgrades are purchased or renovation documentation is complete can reduce the value of the assessment.

A home energy rating may be useful before:

• planning a renovation
• replacing heating or cooling systems
• upgrading insulation
• installing solar or batteries
• planning electrification
• listing a property for sale
• preparing a rental property
• reviewing a residential property portfolio
• trying to solve comfort problems

Early assessment can help avoid rushed or poorly sequenced energy upgrade decisions.

FAQs

How long does a home energy rating take?

The time required for a home energy rating depends on the property, available documentation, access, site data collection, modelling, review and reporting. A straightforward home with clear information may be faster than a larger, altered or poorly documented dwelling.

What affects the timing of a home energy rating?

Timing can be affected by dwelling size, property complexity, access arrangements, missing plans, renovation history, insulation uncertainty, system information, photos, site data collection and whether follow-up questions are needed.

Does a home energy rating require a site visit?

For many existing home assessment pathways, on-site data collection is required so the dwelling’s layout, construction, systems, appliances and visible performance features can be recorded.

Can missing plans delay a home energy rating?

Missing plans can affect timing because the assessor may need to rely more on site data, photos, observations, available records and permitted assumptions. They do not always prevent a rating, but they can add review time.

How can I speed up a home energy rating?

You can help the process by preparing the property address, available plans, photos, renovation history, insulation details, heating and cooling information, hot water details, solar or battery information and known comfort issues.

When should I request a home energy rating?

It is best to request a home energy rating before major upgrade decisions, renovation documentation, sale preparation, lease preparation or electrification planning move too far forward.

Assessment Timing Review

Need a clearer assessment timeframe?

Send property details, available plans and photos so Certified Energy can review the likely home energy rating pathway and timing.

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Home Energy Rating Preparation

Can You Get a Home Energy Rating Without Original Plans?

Original plans are helpful for a home energy rating, but many existing homes do not have complete documentation.

This is common in established Australian homes. The original drawings may have been lost, never passed on during sale, changed by later renovations or replaced by incomplete real estate floor plans.

In many cases, a home energy rating enquiry can still begin without original plans. The key is to provide the best available information so the assessment pathway can be reviewed.

Why original plans are helpful

Original plans can make a home energy rating easier because they show the layout, room sizes, orientation, elevations, construction details and sometimes window information.

They can also help identify which parts of the dwelling are original and which parts have been extended or renovated. This matters because different parts of the home may have different construction standards, insulation levels or glazing types.

Plans reduce uncertainty, but they do not remove the need to understand the home as it exists now.

Why many existing homes do not have complete plans

It is very common for established homes to have missing or incomplete records. A house may have changed owners several times, been extended over decades or had renovations completed without the full documentation being kept with the property.

In some cases, the only available plan is a marketing floor plan from a real estate listing. In other cases, there may be council records, renovation drawings or informal sketches, but not the original construction documentation.

This does not automatically stop the enquiry. It simply means the assessment review needs to identify what information is available and what may need to be collected or confirmed.

What can be used instead of original plans?

If original plans are unavailable, other information may still help the assessment pathway review.

Useful alternatives may include:

• real estate floor plans
• renovation or extension drawings
• council records or approval documents
• site measurements
• property photos
• photos of windows, systems and external elevations
• records of insulation or glazing upgrades
• heating, cooling and hot water system information
• solar PV or battery documentation
• homeowner descriptions of renovation history

The assessor does not need every document before an enquiry can start. The first step is usually to understand what information exists and whether the missing information can be addressed through the assessment process.

Site data can help fill documentation gaps

For existing homes, site data collection can help provide information that is missing from drawings. This may include layout, dimensions, windows, shading, system information and visible construction details.

Depending on the pathway, data collection may involve an assessor or trained data collector recording the dwelling as it currently exists. In some NatHERS existing homes trial delivery models, data could be collected in the home and then used by assessors off-site to produce a rating.

For more detail about the assessment process, see How Does a NatHERS Existing Home Assessment Work?

Photos can help before the pathway is confirmed

Photos do not replace the assessment, but they can help Certified Energy understand the property before confirming the likely pathway or quote requirements.

Useful photos may include:

• front, rear and side elevations
• main living areas
• windows and external shading
• roof, ceiling or subfloor access points, where safely visible
• heating and cooling systems
• hot water system
• solar inverter, panels or battery equipment
• rooms with comfort issues
• renovated or extended areas

Photos should only be taken from safe and accessible areas. Do not enter roof spaces, subfloor areas or unsafe locations just to gather information.

What if the home has been renovated?

Renovated homes can be assessed, but the missing documentation question becomes more important. A renovation may have changed the dwelling’s layout, construction, insulation, windows, systems or roof form.

Helpful renovation information may include:

• approximate year of renovation
• which rooms or areas changed
• whether insulation was added
• whether windows or doors were replaced
• whether heating, cooling or hot water systems were changed
• whether solar or batteries were added
• photos taken during renovation, if available
• builder or product documentation, if available

Even partial information can help. The goal is to reduce uncertainty where possible.

What information is still needed?

Even without original plans, the assessor will still need enough information to describe the dwelling and its energy-related features.

Useful starting information includes:

• property address
• dwelling type
• approximate year of construction
• number of storeys
• any available plans or sketches
• property photos
• renovation history
• known insulation information
• heating and cooling system details
• hot water system details
• solar or battery information
• known comfort issues

For a broader preparation checklist, see What Information Do You Need for a Home Energy Rating?

What are the limits of rating without plans?

A missing plan does not automatically prevent a rating, but it can create uncertainty. Some details may be hidden, difficult to verify or only partly known.

This may affect how the assessor records information, what assumptions can be used and whether additional site data or clarification is needed before the rating can be completed.

The right approach depends on the property, the assessment pathway and the quality of the information available.

Can a real estate floor plan help?

A real estate floor plan can be helpful as a starting point, especially if it shows room layout, approximate dimensions and the relationship between rooms.

However, real estate plans are usually not designed for energy assessment. They may not show construction details, glazing type, insulation, shading, roof form or system information.

Treat a real estate plan as useful supporting information, not as a complete replacement for assessment data.

Should you request a quote if you do not have plans?

Yes. If you do not have original plans, you can still request a pathway review or quote. The important thing is to provide the information you do have.

Start with the property address, available photos, any drawings or floor plans, renovation history, system information and the reason for requesting the rating.

Certified Energy can then review whether a rating pathway is suitable and what further information may be needed.

FAQs

Can you get a home energy rating without original plans?

Original plans are helpful, but they are not always essential for a home energy rating. Many existing homes can still be reviewed using available drawings, site data, photos, observations, system information and permitted assumptions under the relevant assessment pathway.

What can be used instead of original plans?

Useful alternatives may include current floor plans, renovation drawings, real estate plans, site measurements, property photos, system details, renovation history, council records and on-site data collection.

Are original plans required for NatHERS Existing Homes?

Plans can support a NatHERS Existing Homes assessment, but existing homes often have incomplete documentation. The assessor needs enough reliable evidence and data to complete the assessment under the relevant pathway and technical requirements.

What if my home has been renovated but I do not have drawings?

If a home has been renovated without available drawings, provide any information you have, such as approximate dates, photos, invoices, product details, council records or descriptions of what changed. The assessor can confirm what else may need to be checked.

Can photos help with a home energy rating?

Yes. Photos can help clarify the dwelling before the assessment pathway is confirmed. Useful photos may include elevations, rooms, windows, shading, heating and cooling systems, hot water, solar equipment and safely visible insulation or access areas.

Should I request a quote if I do not have plans?

Yes. You can usually begin by sending the property address, available photos, any documents you do have and the reason for the rating. The assessment pathway can then be reviewed.

Assessment Pathway Review

No original plans available?

Send your property address, available photos and any documents you have so Certified Energy can review whether a home energy rating pathway is suitable.

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Home Energy Rating Assessment

What Does a Home Energy Rating Assessor Look For?

A home energy rating assessor looks for the building features and installed systems that influence how an existing home performs.

For an existing home, the assessment is not just a quick visual inspection. It involves collecting structured information about the dwelling, including the building fabric, orientation, windows, insulation, shading, heating and cooling, hot water, solar, batteries and comfort issues.

The aim is to understand how the home performs now, why it may feel uncomfortable or expensive to run, and what information is needed to support a reliable rating or upgrade pathway.

Why the assessor’s review matters

Existing homes are rarely as simple as a clean set of architectural drawings. A home may have been extended, re-roofed, renovated, insulated, fitted with solar or upgraded with new heating and cooling systems over many years.

The assessor’s role is to turn that real-world condition into structured assessment information. This means looking at both the visible parts of the dwelling and the available documentation that can support the rating.

For a broader explanation of the process, see How Does a NatHERS Existing Home Assessment Work?

The assessor looks at layout and orientation

The layout and orientation of a home influence how it receives sun, shade, wind and heat across the day and year. They also affect how rooms are heated, cooled and ventilated.

The assessor may record:

• dwelling type and number of storeys
• room layout and approximate zoning
• orientation of main living spaces
• exposure to sun and shade
• relationship between windows, rooms and outdoor spaces
• whether certain rooms are more exposed than others

This helps explain why some spaces may overheat, stay cold or require more heating and cooling than others.

The assessor looks at the building fabric

The building fabric is the physical shell of the home. It includes the parts of the dwelling that separate inside from outside and influence heat gain, heat loss and comfort.

The assessor may consider:

• roof and ceiling construction
• external wall construction
• floor and subfloor conditions
• construction materials
• thermal mass
• external doors
• visible gaps, draught paths or weak points
• areas affected by additions or renovations

This part of the assessment helps show how much the home relies on mechanical systems to remain comfortable.

The assessor looks for insulation information

Insulation is one of the most important performance factors in many existing homes, but it is not always easy to confirm. Older homes may have no records, partial insulation or insulation added during previous upgrades.

The assessor may look for information about:

• ceiling insulation
• roof insulation
• wall insulation
• floor insulation
• insulation added during renovations
• visible insulation in accessible areas
• insulation product information, where available
• areas where insulation is missing or uncertain

If insulation cannot be safely viewed or documented, the assessor may need to record the uncertainty and apply the relevant assessment pathway rules.

The assessor looks at windows, glazing and shading

Windows can have a large effect on comfort and energy use. They influence solar heat gain, heat loss, daylight, ventilation and how rooms respond to different seasons.

The assessor may review:

• window size and location
• orientation of windows
• glazing type, where identifiable
• frame type
• eaves, awnings and verandahs
• external blinds or shading devices
• nearby buildings, fences or landscape shading
• rooms affected by glare or overheating

This information helps connect the home’s design and exposure to its heating and cooling needs.

The assessor looks at heating and cooling systems

Heating and cooling systems influence how much energy the home uses to remain comfortable. The assessor may need to record the type of systems installed and how they serve the dwelling.

Relevant details may include:

• air conditioning type
• heating system type
• system locations
• zoned or whole-home systems
• approximate system age, if known
• model information or labels
• whether systems are still in use
• rooms that remain uncomfortable despite system use

This does not mean the assessor is only checking appliances. The performance of the building fabric still has a major influence on how hard those systems need to work.

The assessor looks at hot water and major energy systems

Depending on the assessment pathway, the assessor may also collect information about major fixed systems that affect whole-of-home energy performance.

This may include:

• hot water system type
• lighting
• major fixed appliances
• pool or spa equipment, where relevant
• recent electrification upgrades
• system labels or model details
• known issues with system performance

These systems help complete the picture of how the home uses energy beyond heating and cooling alone.

The assessor looks at solar and batteries, where relevant

Solar PV and batteries may influence whole-of-home energy performance, depending on the assessment pathway.

Useful information may include:

• solar PV system size, if known
• inverter details
• battery details, if installed
• installation date, if known
• photos of system labels
• whether the system is currently operating

Solar and batteries can reduce grid energy use, but they do not replace the need to understand the building fabric, comfort and heating and cooling demand.

The assessor asks about comfort issues

Comfort issues can help explain how the home is experienced in daily life. They do not replace assessment data, but they provide useful context.

Useful comfort information may include:

• rooms that overheat in summer
• rooms that stay cold in winter
• areas affected by draughts
• rooms with harsh sun or glare
• rooms that are difficult to heat or cool
• condensation, dampness or moisture concerns
• areas where the home relies heavily on mechanical heating or cooling

This information helps connect the rating to the lived reality of the home, rather than only treating it as a technical exercise.

The assessor identifies what is known and what is uncertain

One of the most important parts of an existing home assessment is identifying the difference between known information and uncertain information.

Some details may be confirmed from plans, labels, receipts, observations or homeowner records. Other details may be unknown, hidden or only partly visible.

This is why original plans are helpful, but not always available. For that specific question, see Can You Get a Home Energy Rating Without Original Plans?

What is the assessor not looking for?

A home energy rating assessment is not the same as a general building inspection, pest inspection, structural engineering review or electrical safety audit.

The assessor is focused on energy performance, comfort, relevant building features and energy-related systems. If structural, safety, moisture or electrical concerns are identified, those may need to be referred to the appropriate specialist.

This distinction helps avoid confusion about what a home energy rating is designed to do.

How to prepare before the assessor reviews the property

You do not need perfect documentation before making an enquiry, but preparation can make the process smoother.

Useful information may include:

• property address
• available floor plans or drawings
• renovation or extension history
• photos of the home
• known insulation information
• heating and cooling system details
• hot water system details
• solar PV or battery details
• known comfort issues
• reason for requesting the rating

For a full preparation checklist, see What Information Do You Need for a Home Energy Rating?

FAQs

What does a home energy rating assessor look for?

A home energy rating assessor looks for the physical features and systems that influence energy performance, comfort and upgrade potential. This may include layout, orientation, insulation, windows, shading, heating and cooling, hot water, lighting, appliances, solar, batteries and comfort issues.

Does a home energy rating assessor check insulation?

Yes. Insulation is an important part of many home energy rating assessments. The assessor may review ceiling, roof, wall or floor insulation where this information is visible, documented or able to be assessed under the relevant pathway.

Does a home energy rating assessor check windows?

Yes. Windows, glazing and shading can significantly affect heat gain, heat loss, daylight and comfort. An assessor may review window size, orientation, glazing type, frame type and external shading.

Will the assessor look at heating and cooling systems?

Yes. Heating and cooling systems are usually relevant because they affect energy use and comfort. The assessor may record system type, location, age, efficiency information and how the systems serve the dwelling.

Does the assessor need access to every room?

For an existing home assessment, access to relevant rooms and areas may be needed so the dwelling layout, windows, systems and visible building features can be recorded. Exact access requirements depend on the assessment pathway and property.

Can an assessor complete a rating without original plans?

Original plans are helpful but not always available for existing homes. Depending on the pathway, the assessor may use available documentation, site data, photos, observations and permitted assumptions where information is incomplete.

Assessment Preparation

Preparing for a home energy rating?

Send your property details, available plans and photos so Certified Energy can review the likely assessment pathway.

Send property details for review

Home Energy Rating

Who Can Request a Home Energy Rating?

A home energy rating can be useful for more than one type of person or project.

Homeowners, buyers, sellers, landlords, renters, renovators, property managers, designers and real estate professionals may all want to understand how an existing home performs for energy efficiency, comfort and upgrade potential.

The important distinction is that a rating can be requested by different parties, but a formal assessment usually needs appropriate property access, the right assessment pathway and a qualified assessor where a certificate is required.

Homeowners can request a home energy rating

Homeowners are one of the most natural groups to request a rating. They may want to understand why the home feels hot, cold, draughty or expensive to run.

A rating can help a homeowner understand the current performance of the dwelling and identify which upgrades may be worth considering first. This may include insulation, glazing, shading, heating and cooling, hot water, solar, batteries or staged renovation measures.

For a broader definition, see What Is a Home Energy Rating for Existing Homes?

Buyers may want a rating before purchasing

Buyers may be interested in a home energy rating because comfort and running costs are not always obvious during an inspection.

A home may present well visually but still have poor insulation, weak glazing, inefficient systems or rooms that overheat or stay cold. A rating can help a buyer understand the likely performance of the property before making longer-term decisions.

In practice, a buyer may need permission from the owner or agent before a formal assessment can occur, because property access is usually required.

Sellers may request a rating before listing a property

Sellers may request a home energy rating to better understand how the home performs before it is listed for sale.

This may be useful where the home has been upgraded, renovated, insulated, electrified or fitted with solar and batteries. A rating can help make energy performance easier to explain in a structured way.

It may also become more relevant as home energy rating disclosure pathways continue to develop in Australia. For the current position, see Are Existing Home Energy Ratings Mandatory in Australia?

Landlords and rental property owners can request a rating

Landlords may request a home energy rating to better understand the comfort and performance of a rental property.

This can be helpful when planning upgrades, preparing for future disclosure expectations, improving tenant comfort or reviewing the long-term condition of a property portfolio.

For rental properties, access arrangements may need to be coordinated with the tenant, property manager or managing agent.

Renters may be interested, but access and permission matter

Renters may want to understand a home’s energy performance, especially where the property is uncomfortable, expensive to heat or cool, or difficult to live in during extreme weather.

However, a formal assessment will usually require property access and may involve areas or systems that are controlled by the owner or managing agent.

This means renters may be able to ask about a rating or encourage one, but the practical assessment pathway usually needs owner or agent approval.

Renovators can request a rating before upgrade decisions

Renovators can use a home energy rating to understand the existing dwelling before committing to upgrade decisions.

This can help identify whether the priority is insulation, windows, shading, draught sealing, heating and cooling, hot water, solar, batteries or a broader staged retrofit pathway.

For renovation projects, a rating may also help design teams understand how the existing home performs before proposed changes are locked in.

Designers, builders and project teams may request support

Architects, building designers, builders and project teams may request home energy rating support when working on an existing dwelling.

This is particularly useful where a project needs to understand real built performance before making design or construction decisions. It can also help separate existing-home performance advice from new-home NatHERS compliance.

For that distinction, see NatHERS Existing Homes vs New Home NatHERS Assessments.

Real estate agents and property managers may coordinate a rating

Real estate agents and property managers may become involved in home energy ratings where a seller, landlord, buyer, renter or property owner wants clearer performance information.

They may help coordinate access, provide property information, communicate with owners or tenants, and help explain why a rating is being requested.

As disclosure pathways develop, property professionals may need to become more familiar with how ratings work and when they are useful.

Who can issue the rating or certificate?

It is important to separate who can request a rating from who can issue the formal certificate.

A homeowner, buyer, seller, landlord, renter or project team may be interested in a rating. But for NatHERS Existing Homes, a Home Energy Rating Certificate can only be generated by an accredited existing homes assessor.

This is why it is useful to confirm the pathway early rather than assuming that any general energy review will produce the same outcome.

When should someone request a home energy rating?

A home energy rating is most useful when it supports a real decision.

Common times to request a rating include:

• before planning energy upgrades
• before a renovation or extension
• before replacing heating or cooling systems
• before electrification works
• before installing solar or batteries
• before listing a property for sale or lease
• when reviewing a rental property
• when assessing a residential property portfolio
• when trying to understand comfort problems

The earlier the rating is considered, the easier it may be to avoid rushed or poorly sequenced upgrade decisions.

What information should be prepared before requesting a rating?

A request does not need to begin with perfect documentation. However, it is helpful to prepare the information that is available.

Useful information may include:

• property address
• dwelling type
• available plans or photos
• renovation or extension history
• known insulation details
• heating and cooling system information
• hot water system information
• solar or battery information
• known comfort issues
• reason for requesting the rating

For a full preparation checklist, see What Information Do You Need for a Home Energy Rating?

FAQs

Who can request a home energy rating?

A home energy rating may be requested by homeowners, buyers, sellers, landlords, renters, renovators, real estate professionals, property managers, designers or project teams, depending on the purpose of the assessment and access to the property.

Can a homeowner request a home energy rating?

Yes. Homeowners can request a home energy rating to understand comfort, energy performance, upgrade priorities, renovation planning or future disclosure readiness.

Can a buyer request a home energy rating before purchasing?

A buyer may want energy performance information before purchasing, but the assessment will usually require appropriate property access and permission. The practical pathway depends on the sale process and the cooperation of the owner or agent.

Can a landlord request a home energy rating?

Yes. Landlords and rental property owners may request a home energy rating to understand comfort, running cost factors, upgrade opportunities and possible future disclosure or rental property performance expectations.

Can a renter request a home energy rating?

A renter may be interested in a home energy rating, but a formal assessment will usually require property access and the owner or managing agent’s approval.

Who can issue a NatHERS existing home certificate?

A NatHERS existing Home Energy Rating Certificate can only be generated by an accredited existing homes assessor.

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Home Energy Rating

Does a Home Energy Rating Provide a Star Rating?

A home energy rating may provide a star rating, but the star rating is only one part of the wider performance picture.

For many homeowners, the idea of a star rating is familiar because NatHERS has long used stars to describe the thermal performance of new homes. As NatHERS expands into existing homes, star rating language is also becoming relevant to established dwellings.

The key is to understand what the star rating does, what it does not measure, and how it differs from broader whole-of-home energy performance.

What does the star rating mean?

The NatHERS star rating describes the thermal performance of a home. It helps explain how much heating and cooling the dwelling is likely to need to remain comfortable in its climate.

A higher star rating generally means the home is better at staying comfortable with less energy for heating and cooling. A lower star rating generally means the home may be more expensive or difficult to keep comfortable.

For an existing home, this can be useful because it gives the homeowner a clearer performance signal than simply saying the home feels hot, cold or expensive to run.

What influences the star rating?

The thermal star rating is influenced by the way the home is designed, built and exposed to its climate.

Key factors may include:

• climate zone
• orientation
• dwelling layout
• roof, wall and floor construction
• ceiling, wall and floor insulation
• window size and placement
• glazing type
• external shading
• thermal mass
• air movement and ventilation
• draughts or air leakage
• renovation and extension history

In existing homes, some of these details may be easy to identify. Others may need to be confirmed through plans, site observations, photos, homeowner information or assessment assumptions.

Is the star rating the same as whole-of-home performance?

No. The thermal star rating and whole-of-home performance are related, but they are not the same thing.

The thermal star rating focuses on the building’s heating and cooling needs. It is mainly about how well the dwelling itself manages heat gain, heat loss and thermal comfort.

Whole-of-home performance may also consider major energy systems and generation, such as hot water, heating and cooling systems, lighting, appliances, solar PV and batteries. This gives a broader view of energy use across the home.

Why the star rating is not the whole answer

A star rating is a useful summary, but it does not explain everything on its own.

For example, two homes may have similar thermal ratings but very different hot water systems, appliance loads, solar systems or battery storage. One may have strong building fabric but inefficient systems. Another may have solar panels but still overheat because of poor shading or glazing.

This is why a home energy rating should be interpreted with the wider assessment information, not only the star number.

Is an existing home star rating the same as a new home rating?

The rating language may be similar, but the assessment context is different.

A new home NatHERS assessment usually rates a proposed design before it is built. It is commonly used for compliance and design-stage decision-making.

An existing home rating assesses a dwelling that already exists. It must respond to real construction, previous renovations, installed systems, missing documentation and the current condition of the home.

For a detailed comparison, see NatHERS Existing Homes vs New Home NatHERS Assessments.

Does a 7 Star requirement apply to existing homes?

The 7 Star conversation is mainly connected to new-home energy efficiency standards under the National Construction Code and state implementation.

Existing home ratings are different. They help assess current performance and identify possible upgrades, but they should not be confused with a new-home compliance requirement.

A homeowner may still want to improve the rating of an existing home, but the assessment should be understood as a performance and improvement pathway, not simply a new-build compliance test.

What appears on a Home Energy Rating Certificate?

A Home Energy Rating Certificate may show the home’s assessed energy performance and provide information that can help guide comfort and upgrade decisions.

The exact certificate format can depend on the assessment pathway and rollout stage. In the NatHERS existing homes trial, participating households received a trial certificate that included a star rating out of 10 and a home energy rating out of 100.

For homeowners, the most useful approach is to treat the certificate as a starting point for understanding performance, not as a replacement for practical assessment advice.

Can the rating help identify upgrades?

Yes. A rating can help identify where an existing home may be improved.

Possible upgrade areas may include:

• ceiling, wall or floor insulation
• draught sealing
• window and glazing improvements
• external shading
• heating and cooling replacement
• hot water upgrades
• solar PV and battery systems
• ventilation improvements
• staged renovation measures

The important question is sequencing. A good assessment can help a homeowner understand which measures should be considered first, rather than treating every upgrade as equal.

Does a higher star rating guarantee lower bills?

A higher star rating generally indicates that the home should need less heating and cooling to remain comfortable. This can support lower running costs, especially when compared with a similar home in the same climate and usage pattern.

However, energy bills are also affected by household behaviour, tariffs, occupancy, appliances, pool equipment, work-from-home patterns, thermostat settings and how systems are used.

This is why the rating should be read as performance information, not as a guarantee of a specific bill amount.

What information is needed to produce a rating?

To produce a rating, the assessor needs enough information about the dwelling and its systems. For existing homes, this may include property details, available plans, site data, photos, renovation history, insulation details and system information.

Useful preparation may include:

• property address
• available plans or drawings
• renovation history
• photos of the home
• known insulation details
• window and glazing information
• heating and cooling system details
• hot water system details
• solar or battery information
• known comfort issues

For a practical checklist, see What Information Do You Need for a Home Energy Rating?

How the star rating fits into the existing homes pathway

As NatHERS expands into existing homes, star ratings help bring a familiar performance language into established dwellings.

This can help homeowners, buyers, sellers, landlords and property professionals understand a home’s performance more clearly. It may also support future disclosure conversations as rating pathways continue to develop.

For more context, see What Is NatHERS Existing Homes?

FAQs

Does a home energy rating provide a star rating?

A home energy rating may provide a star rating, depending on the assessment pathway. Under NatHERS, homes can receive a thermal star rating from 0 to 10, where a higher rating generally means the home is more comfortable and cheaper to run.

What does the NatHERS star rating mean?

The NatHERS thermal star rating describes how well the home performs thermally. It reflects how much heating and cooling the home is likely to need to remain comfortable, based on features such as layout, orientation, insulation, windows, shading and climate.

Is the star rating the same as the whole home energy rating?

No. The thermal star rating and whole-of-home energy performance are related but not the same. The star rating focuses on thermal performance, while whole-of-home performance may also consider appliances, hot water, solar, batteries and other energy uses.

Does a higher star rating mean lower energy bills?

A higher star rating generally indicates a home should need less heating and cooling to remain comfortable. However, actual energy bills also depend on household behaviour, tariffs, occupancy, appliances and system use.

Can an existing home improve its star rating?

An existing home may be able to improve its rating through upgrades such as insulation, draught sealing, window improvements, shading, efficient heating and cooling, hot water upgrades, solar or batteries. The best sequence depends on the home.

Is a 7 Star rating required for existing homes?

7 Star requirements are mainly connected to new-home energy efficiency standards under the National Construction Code. Existing home ratings help assess current performance and upgrade potential, but they should not be confused with new-home compliance requirements.

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Home Energy Rating

What Does a Home Energy Rating Actually Measure?

A home energy rating measures how a dwelling performs as a home, not just how much energy appears on a bill.

For existing homes, the assessment may look at the building fabric, thermal comfort, windows, insulation, heating and cooling, hot water, solar, batteries and potential upgrade opportunities.

The purpose is to help homeowners, buyers, sellers, landlords and project teams understand how an established dwelling performs now, and what may improve its comfort and energy efficiency over time.

It measures the home as a whole system

A home energy rating is most useful when it looks at the home as a connected system. The walls, roof, floor, windows, shading and installed systems all affect comfort and energy demand.

For example, an efficient air conditioner may still struggle in a home with poor insulation, large unshaded windows or major draughts. Solar panels may reduce grid electricity use, but they do not necessarily solve overheating, winter heat loss or poor thermal comfort.

This is why a home energy rating for existing homes needs to consider both the building and the systems that support it.

It measures the building fabric

The building fabric is the physical shell of the home. It includes the elements that separate inside from outside and influence how quickly heat enters or leaves the dwelling.

This may include:

• roof and ceiling construction
• external walls
• floors and subfloor conditions
• insulation levels
• windows and glazing
• external doors
• thermal mass
• construction materials
• areas affected by draughts or gaps

Building fabric matters because it often determines how much heating or cooling the home needs before any appliance is even switched on.

It measures insulation where information is available

Insulation is one of the main factors that can influence a home’s heating and cooling needs. A home with poor or missing insulation may lose heat quickly in winter and gain heat quickly in summer.

The assessment may consider insulation in:

• ceilings
• roofs
• walls
• floors
• extensions or renovated areas
• areas where insulation may be missing, damaged or uncertain

In existing homes, insulation is not always easy to verify. The assessor may need to work with available plans, photos, site observations, renovation records and permitted assumptions.

It measures windows, glazing and shading

Windows can have a major effect on comfort and energy use. They influence heat gain, heat loss, daylight, ventilation and exposure to sun.

A home energy rating may consider:

• window size and location
• orientation
• glazing type
• window frame type
• external shading
• eaves, awnings and verandahs
• nearby obstructions
• rooms affected by glare or overheating

This is especially important in Australian homes where summer heat gain, winter heat loss and sun exposure can vary significantly by climate and orientation.

It measures heating and cooling needs

Thermal performance is one of the clearest parts of a home energy rating. It helps explain how much heating or cooling a home is likely to need to remain comfortable.

This is influenced by the design and construction of the home, not only by the appliances installed. A well-insulated, well-shaded home may need less active heating and cooling. A poorly sealed or poorly insulated home may need more energy to remain comfortable.

For existing homes, this can help explain why some rooms are difficult to heat, why certain spaces overheat, or why energy use remains high even after appliance upgrades.

It may measure hot water and major fixed appliances

Depending on the rating pathway, a home energy rating may also consider major fixed systems that contribute to household energy use.

These may include:

• hot water systems
• heating systems
• cooling systems
• lighting
• pool or spa equipment, where relevant
• major fixed appliances
• on-site solar PV
• battery storage

This is where the assessment starts to move beyond the shell of the building and into whole-of-home energy performance.

It may measure solar and batteries

Solar PV and batteries can influence how much energy a home draws from the grid. Depending on the assessment pathway, they may be included as part of whole-of-home performance.

This does not mean that solar alone makes a home comfortable or efficient. A home with solar panels can still have poor insulation, overheating, draughts or high heating and cooling demand.

The rating is most useful when solar and batteries are considered alongside the building fabric and installed systems.

It helps explain comfort issues

Many homeowners first become interested in a home energy rating because the home feels uncomfortable. Some rooms may overheat. Others may stay cold. Some areas may be draughty, damp or difficult to condition.

Useful comfort information may include:

• rooms that are too hot in summer
• rooms that are too cold in winter
• areas with noticeable draughts
• rooms affected by harsh sun or glare
• rooms that are difficult to heat or cool
• moisture or condensation concerns
• areas where the home relies heavily on mechanical heating or cooling

This context helps connect the rating to the lived experience of the home.

It can help identify upgrade potential

One of the practical benefits of a home energy rating is that it can help identify where improvements may be most useful.

Possible upgrade areas may include:

• ceiling, wall or floor insulation
• draught sealing
• window and glazing improvements
• external shading
• heating and cooling replacement
• hot water system upgrades
• solar PV and batteries
• ventilation improvements
• staged renovation measures

The value is not just the list of possible upgrades. It is the sequencing. A rating can help homeowners understand whether the first step should be improving the building fabric, replacing systems, reviewing solar or planning upgrades as part of a renovation.

It is not just a review of energy bills

Energy bills can be useful context, but they do not tell the full story of the home. Bills are affected by household size, behaviour, tariffs, climate, appliance use and whether people work from home.

Two homes with similar bills may perform very differently. One may be efficient but heavily occupied. Another may be inefficient but used lightly. A home energy rating is intended to give a more structured understanding of the dwelling itself.

This is why the assessment focuses on physical features, systems and likely performance rather than treating a bill as the rating.

The exact measurement depends on the pathway

Different home energy rating pathways may have different inputs, certificate formats, software requirements and reporting outputs.

NatHERS Existing Homes, Residential Efficiency Scorecard and other home energy assessment approaches may not all present information in exactly the same way. The important point is to confirm which pathway applies before assuming what will be measured or reported.

For the NatHERS pathway, see What Is NatHERS Existing Homes?

What information helps the assessment?

Because a home energy rating measures the dwelling and its systems, the assessment is easier when useful information is available.

Helpful information may include:

• property address
• available floor plans or drawings
• renovation history
• photos of the home
• insulation information, if known
• heating and cooling system details
• hot water system details
• solar or battery information
• known comfort issues

For a practical preparation checklist, see What Information Do You Need for a Home Energy Rating?

FAQs

What does a home energy rating measure?

A home energy rating measures how a dwelling performs for energy efficiency, comfort and likely energy use. For existing homes, it may consider the building fabric, insulation, windows, shading, heating and cooling, hot water, appliances, solar, batteries and upgrade potential.

Does a home energy rating measure insulation?

Yes. Insulation is one of the key elements that can influence a home energy rating. The assessment may consider ceiling, roof, wall and floor insulation where this information is available, observable or able to be assessed under the relevant pathway.

Does a home energy rating measure heating and cooling?

Yes. A home energy rating may consider heating and cooling needs, installed systems and how the dwelling manages heat gain and heat loss. This helps explain comfort and likely energy demand.

Does a home energy rating include solar panels and batteries?

Depending on the rating pathway, solar PV and batteries may be considered as part of whole-of-home energy performance. These systems can influence how much energy the home uses from the grid.

Does a home energy rating measure energy bills?

A home energy rating is not the same as an energy bill review. Bills are affected by tariffs, occupancy and behaviour. The rating focuses more directly on the dwelling, its systems and its likely performance.

Can a home energy rating identify upgrade opportunities?

Yes. A home energy rating can help identify possible upgrade opportunities, such as insulation improvements, glazing changes, draught sealing, more efficient systems, solar, batteries or staged renovation measures.

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NatHERS Existing Homes

What Is NatHERS Existing Homes?

NatHERS Existing Homes is the expansion of Australia’s Nationwide House Energy Rating Scheme into homes that have already been built.

For many years, NatHERS has been most familiar as a new-home rating system used during design and compliance. The existing homes pathway extends the same national rating language into established dwellings, helping homeowners and property teams understand how a real home performs now.

This matters because an existing home is not a proposed design. It has already been built, occupied, altered and maintained over time. A NatHERS Existing Homes assessment is intended to help make that real performance easier to understand.

Why was NatHERS expanded to existing homes?

Australia already has a long-established rating system for new homes. But most homes in Australia have already been built, and many were constructed before current energy efficiency expectations were introduced.

Existing homes can be difficult for households to understand. A home may look well presented but still perform poorly in summer or winter. It may have high running costs, weak insulation, inefficient systems, poor glazing or comfort problems that are not obvious during a standard property inspection.

NatHERS Existing Homes gives a more consistent way to describe this performance. It helps shift the conversation from guesswork toward a structured assessment of how the home actually performs.

How does this relate to a Home Energy Rating?

A Home Energy Rating is the broader consumer-facing idea: a way to understand how an existing home performs for energy use, comfort and potential upgrades.

NatHERS Existing Homes is one of the key national pathways supporting this shift. It sits within the NatHERS framework and provides a more consistent language for rating existing dwellings.

For a broader definition, see What Is a Home Energy Rating for Existing Homes?

What does NatHERS Existing Homes assess?

A NatHERS Existing Homes assessment looks at the dwelling as it exists, not only as it may have been designed. The exact information required depends on the assessment pathway, available documentation and the condition of the home.

The assessment may consider:

• dwelling layout and construction type
• orientation and climate context
• roof, wall and floor insulation
• windows, glazing and shading
• heating and cooling systems
• hot water systems
• lighting and major fixed appliances
• solar PV and batteries
• ventilation and draughts
• comfort issues and upgrade opportunities

The purpose is not only to produce a number. A useful assessment can help a homeowner understand what is influencing performance and where improvements may be most effective.

How is it different from new home NatHERS?

The core difference is timing and purpose.

New home NatHERS usually assesses a proposed design before construction. It is commonly used for compliance, certification and design-stage decision-making. The assessor works from drawings, specifications and construction details.

NatHERS Existing Homes assesses a dwelling that has already been built. It must respond to real construction, previous renovations, installed systems, missing documentation and the actual condition of the home.

For a detailed comparison, see NatHERS Existing Homes vs New Home NatHERS Assessments.

Who can provide a NatHERS Existing Homes certificate?

NatHERS existing Home Energy Rating certificates can only be generated by an accredited existing homes assessor.

This distinction matters because existing homes require specific assessment processes. The assessor may need to deal with incomplete documentation, site data, assumptions, existing systems and real-world construction conditions.

For clients, this means the right pathway should be confirmed before assuming that a standard new-home NatHERS assessment is suitable.

Is NatHERS Existing Homes mandatory?

Existing home energy ratings are not yet mandatory across Australia as a universal requirement. However, disclosure pathways are developing, and requirements may vary by jurisdiction, program or transaction type over time.

This is why the wording needs to be careful. NatHERS Existing Homes should be understood as an emerging and expanding assessment pathway, not as a blanket requirement for every existing home today.

For a fuller explanation, see Are Existing Home Energy Ratings Mandatory in Australia?

Who is NatHERS Existing Homes for?

NatHERS Existing Homes may be useful for homeowners who want to understand how their home performs and what upgrades may be worth considering.

It may also be relevant for buyers, sellers, landlords, rental property owners, renovation teams, real estate professionals and organisations reviewing residential portfolios.

The pathway is especially useful where a client needs to understand an established dwelling rather than a proposed new design.

What information is usually needed?

The required information depends on the home and assessment pathway. As a starting point, it is helpful to prepare the property address, available plans, renovation history, photos and details of major systems.

Useful information may include:

• property address and dwelling type
• available floor plans or drawings
• renovation or extension history
• known insulation information
• window and glazing details, if known
• heating and cooling system details
• hot water system details
• solar PV or battery information
• known comfort issues

If the documentation is incomplete, the assessment may still be possible. The pathway can be reviewed based on the information that is available.

Common misunderstandings

One common misunderstanding is that NatHERS Existing Homes is simply the same as a new home NatHERS assessment. It is not. The existing homes pathway deals with real dwellings, not only proposed designs.

Another misunderstanding is that the rating only relates to energy bills. Bills can be influenced by behaviour, tariffs and occupancy. The assessment is more useful when it helps describe the dwelling’s performance and possible improvement opportunities.

A third misunderstanding is that every existing home must already have a rating. This is not the current national position. The disclosure landscape is developing, but it should not be overstated.

A fourth misunderstanding is that a rating automatically means one specific upgrade is required. In practice, the value of the assessment is that it can help clarify the home’s performance and support better decision-making.

Practical implications

For homeowners, NatHERS Existing Homes can help turn general concerns about comfort and energy use into clearer performance information.

For renovators and design teams, it can help identify existing performance issues before upgrade decisions are locked in.

For sellers, landlords and property professionals, it may become increasingly relevant as home energy disclosure pathways develop.

For consultants, the key is to separate the existing homes pathway from new-home compliance and guide clients toward the correct assessment type.

FAQs

What is NatHERS Existing Homes?

NatHERS Existing Homes is the expansion of the Nationwide House Energy Rating Scheme into established dwellings. It helps assess the energy performance, comfort and upgrade potential of homes that have already been built.

Is NatHERS Existing Homes the same as new home NatHERS?

No. New home NatHERS usually assesses a proposed residential design before construction for compliance purposes. NatHERS Existing Homes assesses a dwelling that already exists and focuses on current performance and improvement opportunities.

What does NatHERS Existing Homes assess?

A NatHERS Existing Homes assessment may consider the dwelling’s construction, insulation, glazing, shading, heating and cooling systems, hot water, appliances, solar, batteries, ventilation, comfort and possible upgrade opportunities.

Who can provide a NatHERS Existing Homes certificate?

NatHERS existing Home Energy Rating certificates can only be generated by an accredited existing homes assessor.

Is NatHERS Existing Homes mandatory?

Existing home energy ratings are not yet mandatory across Australia as a universal requirement. Disclosure pathways are developing, and requirements may vary over time by jurisdiction, program or transaction type.

Why is NatHERS being expanded to existing homes?

The expansion helps households better understand the performance of homes that have already been built, including comfort, energy use and potential upgrades.

Existing Home Assessment Pathways

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