Building Fabric

Glazing and Shading in Existing Homes

Glazing and shading can strongly influence how an existing home feels throughout the year.

Windows bring light, outlook, ventilation and winter solar warmth into a home. But they can also create summer overheating, winter heat loss, glare and rooms that are difficult to heat or cool.

For existing homes, the question is not only whether the windows are single or double glazed. It is also whether the glass is facing the right direction, whether it is shaded at the right time, and how the window system works with insulation, ventilation and heating or cooling.

Why glazing and shading matter in existing homes

Windows are often one of the weakest parts of the building fabric. They usually perform differently from insulated walls, roofs and floors because glass allows light, heat and solar radiation to pass through in ways opaque building elements do not.

In winter, windows can lose heat and make nearby rooms feel cold. In summer, windows can admit unwanted solar heat and create overheating. If shading is poor, the room may become uncomfortable before the air conditioner is even switched on.

This is why glazing and shading should be reviewed together rather than treated as separate issues.

What does glazing mean?

Glazing refers to the glass in windows, doors and skylights, as well as the wider window system that affects performance. In practical assessment, window performance is influenced by the glass, frame, seals, orientation, size and exposure.

Common glazing types include single glazing, double glazing, low-e glass, tinted glass and other performance glass products. The right choice depends on the home, climate, orientation and whether the main problem is summer heat gain, winter heat loss, glare or comfort near the glass.

For a home energy rating, glazing is not only a product choice. It is part of how the building performs as a whole.

What does shading mean?

Shading refers to anything that controls direct sun on windows, glazing and sometimes walls or outdoor areas. It can be fixed, adjustable, external, internal or created by nearby structures.

Common shading elements include:

• eaves and roof overhangs
• awnings
• external blinds
• screens and shutters
• verandahs and pergolas
• balconies and upper floors
• nearby buildings or boundary structures
• internal blinds or curtains, where relevant to comfort

External shading is often especially effective because it reduces direct sun before it passes through the glass.

Two important glazing concepts: U-value and SHGC

Window performance is often described through two important concepts: U-value and Solar Heat Gain Coefficient, or SHGC.

U-value relates to how readily heat conducts through the window system. A lower U-value generally means the window is better at resisting heat transfer. SHGC relates to how much solar heat the glazing allows into the home from direct sunlight.

This matters because a window that performs well for winter heat loss may not automatically solve summer heat gain. The best window strategy depends on orientation, climate and shading.

Orientation changes how windows perform

The same window can behave differently depending on which direction it faces. In Australia, north, east, west and south-facing glazing can create very different comfort outcomes.

North-facing windows can often be shaded more predictably with well-designed horizontal shading. East and west-facing windows can be more difficult because low-angle morning and afternoon sun can penetrate deeply and create heat gain. South-facing windows may receive less direct sun in many locations but can still contribute to heat loss.

This is why a window upgrade should not simply use the same glazing and shading approach on every elevation.

Glazing, shading and summer overheating

Summer overheating is often driven by direct sun on glass. Once solar heat enters a room, it can be difficult to remove without mechanical cooling, especially if the room has poor ventilation or the home stores heat into the evening.

Good shading can reduce unwanted sun before it reaches the glass. In many existing homes, shading can be a more practical first step than replacing every window, especially where the main issue is exposed summer sun.

However, the right solution depends on which windows are causing the problem, how the home is ventilated and what other building fabric issues are present.

Glazing and winter heat loss

Windows can also be a major source of winter heat loss. Rooms near poorly performing windows may feel cold, even when the heating system is running.

Double glazing or other higher-performing glazing systems can help reduce heat loss, but the benefit depends on the whole window system, frame type, installation quality, air leakage and how the room is used.

Window upgrades should therefore be assessed alongside draught sealing, insulation and heating system strategy.

External shading usually works before heat enters the home

External shading is often powerful because it blocks or reduces direct sun before it passes through the glass. Examples include eaves, awnings, external blinds, screens, shutters and verandahs.

Internal blinds and curtains can improve comfort and privacy, and some products can help reduce heat movement. However, once sunlight has already passed through the glass, much of the heat is already inside the room.

For overheating problems, external shading is often worth reviewing before assuming the only answer is air conditioning or full window replacement.

Fixed shading and adjustable shading

Fixed shading includes elements such as eaves, roof overhangs, awnings, pergolas and verandahs. These can be durable and low-maintenance, but they need to be designed carefully for orientation and season.

Adjustable shading includes external blinds, shutters, operable louvres and some screen systems. These can provide more flexibility because they can respond to season, weather, time of day and occupant preference.

In existing homes, adjustable shading can sometimes be a practical retrofit option where fixed shading is difficult to add or where different seasons require different levels of solar access.

How glazing and shading affect a home energy rating

A home energy rating may consider glazing and shading because they influence heating and cooling demand. Window size, location, orientation, glass type, frame type and external shading can all affect the result.

In an existing home, some window information may be easy to identify. Other details may require documentation, product labels, site observations or reasonable assumptions under the relevant assessment pathway.

For more detail on what assessors review, see What Does a Home Energy Rating Assessor Look For?

Glazing and shading do not work alone

Window upgrades can be valuable, but they should not be treated as the only performance measure. A home with better glazing may still perform poorly if insulation is missing, air leakage is high or shading is inadequate.

Likewise, shading can reduce summer heat gain but may not solve winter heat loss, draughts, poor ventilation or inefficient heating and cooling systems.

For that reason, glazing and shading should be assessed as part of the whole-home performance pathway.

Renovation is often the best time to review glazing and shading

Window and shading decisions can be difficult to change later. If a renovation involves new openings, replacement windows, facade changes, decks, pergolas or external works, glazing and shading should be considered early.

This can help avoid situations where a room is newly renovated but still overheats, loses heat or needs more mechanical cooling than expected.

For renovation context, see Existing Home Energy Rating vs Renovation Energy Assessment.

Common mistakes in existing homes

Common glazing and shading issues include:

• large west-facing windows without effective shading
• replacing windows without reviewing orientation
• using the same glazing product on every elevation
• adding internal blinds but ignoring external summer sun
• installing shading that blocks useful winter sun
• upgrading glazing while leaving major draughts unresolved
• assuming double glazing alone will solve overheating
• ignoring nearby built form and site exposure

A good assessment can help separate the visible symptom from the underlying performance issue.

What information helps a glazing and shading review?

Before requesting a home energy rating or upgrade review, it can help to prepare simple information about the windows and shading conditions.

Useful information may include:

• photos of each side of the home
• photos of major windows and doors
• photos of eaves, awnings, pergolas or external blinds
• notes on rooms that overheat or feel cold
• known window replacement history
• glazing product information, if available
• floor plans or real estate plans showing window locations
• renovation drawings, if window changes are proposed

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

FAQs

Why do glazing and shading matter in existing homes?

Glazing and shading matter because windows can drive heat gain, heat loss, glare and comfort problems. In existing homes, poor glazing or inadequate shading can increase heating and cooling demand.

Does a home energy rating assess glazing?

Yes. A home energy rating may consider window size, location, orientation, glazing type, frame type and related window performance information where it can be identified or assessed under the relevant pathway.

Does a home energy rating assess shading?

Yes. Shading may be considered because it affects how much direct sun reaches windows and other glazed areas. The exact shading inputs depend on the assessment pathway and available information.

What is the difference between glazing and shading?

Glazing refers to the glass and window system itself. Shading refers to elements that reduce or control direct sun on the glass, such as eaves, awnings, external blinds, verandahs or nearby built form.

Can better shading reduce overheating?

Yes. Appropriate external shading can help reduce unwanted summer sun on windows, which can reduce overheating and cooling demand. The best shading strategy depends on orientation, climate and window design.

Should glazing be upgraded before or after insulation?

Glazing and insulation should be reviewed together. The best upgrade sequence depends on the home, climate, comfort problems, budget, renovation timing and whether windows, shading or building fabric are the main performance issues.

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Building Fabric

Insulation in Existing Homes

Insulation is one of the most important building fabric elements in an existing home.

It helps slow heat transfer through ceilings, roofs, walls and floors. In practical terms, this can help a home stay warmer in winter, cooler in summer and less dependent on mechanical heating and cooling.

For existing homes, insulation is also one of the areas most likely to be uncertain. It may be missing, incomplete, compressed, damaged, hidden behind finishes or different between the original home and later renovations.

Why insulation matters in existing homes

Many existing Australian homes were built before current energy efficiency expectations were introduced. Some have little insulation. Others have insulation in one part of the home but not another. Some have had upgrades added over time without clear documentation.

This matters because insulation helps the home resist unwanted heat flow. In winter, it can help reduce heat loss. In summer, it can help slow external heat entering the building. Without adequate insulation, heating and cooling systems may need to work harder to maintain comfort.

For homeowners, insulation is often one of the first building fabric issues worth understanding before choosing appliances, solar or other energy upgrades.

How insulation affects a home energy rating

A home energy rating considers how the dwelling performs as a whole system. Insulation is one of the key building fabric inputs because it affects heating and cooling demand.

Where insulation is present and effective, the home may be better able to maintain comfort with less active heating and cooling. Where insulation is missing, incomplete or damaged, the rating may reflect higher thermal loads or poorer comfort performance.

For a broader explanation of assessment inputs, see What Does a Home Energy Rating Actually Measure?

Ceiling and roof insulation

Ceiling and roof insulation are often important because roofs can be a major pathway for heat gain and heat loss. In summer, roof spaces can become very hot. In winter, warm indoor air can be lost through poorly insulated ceilings or roof assemblies.

In existing homes, ceiling insulation may be missing, patchy, compressed, disturbed by trades or inconsistent between old and renovated areas. Roof insulation may also vary depending on the roof type, ceiling type and previous upgrades.

A rating or assessment may need to identify what is known, what is visible and what remains uncertain before insulation performance can be properly understood.

Wall insulation

Wall insulation can be harder to confirm in an existing home because it is usually hidden behind internal linings and external cladding or masonry.

Some older homes may have little or no wall insulation. Some renovations may have added insulation to new walls but left original walls unchanged. This can create uneven comfort between rooms or parts of the house.

Wall insulation is often easiest to review during renovation, when walls are already being opened or upgraded. This is why insulation should be considered early in renovation planning.

Floor insulation

Floor insulation can be relevant where the home has suspended floors, exposed subfloors, garages below living spaces or areas that feel cold underfoot in winter.

Not every home will have the same floor insulation opportunity. A concrete slab behaves differently from a suspended timber floor. Access, moisture conditions, ventilation and construction type all affect what can be assessed or upgraded.

As with other insulation types, floor insulation should be reviewed as part of the whole building fabric rather than treated as a separate product decision.

Renovations can create insulation gaps

Existing homes often contain different layers of construction. The original dwelling may have been built to one standard, while an extension or renovated area may have been built to another.

This can create insulation gaps. A rear extension may be better insulated than the original home. A converted garage may have different wall and roof performance. A renovated living area may have new glazing but no corresponding wall or ceiling upgrade.

Understanding these differences can help explain why one part of a home feels comfortable while another performs poorly.

Insulation is not the only performance issue

Insulation is important, but it does not work alone. A well-insulated home can still overheat if windows are unshaded, if glazing is poorly selected or if summer sun enters the building at the wrong times.

A home with new insulation may still feel draughty if there are air leakage issues. A home with solar panels may still need building fabric improvements if heating and cooling demand remains high.

This is why insulation should be considered alongside glazing, shading, draught sealing, ventilation and mechanical systems.

Insulation and summer overheating

Insulation can help slow heat entering the home, but it is not a complete overheating strategy on its own.

If a home has large unshaded windows, poor ventilation, dark roof surfaces or high internal heat gains, insulation alone may not prevent summer discomfort. In some cases, a home may hold heat for longer if night purging, shading and ventilation are not considered.

This is why overheating should be assessed as a whole-home performance issue, not only an insulation issue.

Insulation and draughts are different issues

Insulation slows heat transfer through building elements. Draught sealing reduces uncontrolled air movement through gaps, cracks and leakage points. Both can affect comfort, but they are not the same thing.

A home can be insulated but still draughty. It can also be relatively well sealed but poorly insulated. The best retrofit strategy often considers both thermal resistance and air leakage together.

This will be covered in more depth in the related article on draught sealing and air leakage in existing homes.

How an assessor may review insulation

In an existing home assessment, the assessor may need to determine what insulation information is available and how reliable it is.

Useful evidence may include:

• visible insulation in accessible areas
• renovation documentation
• builder or installer invoices
• product labels or specifications
• photos taken during previous works
• homeowner records
• plans or construction notes
• safe access observations

Where insulation cannot be verified, the assessment may need to treat that information carefully according to the relevant pathway. For more context, see What Does a Home Energy Rating Assessor Look For?

When should insulation be upgraded?

Insulation may be worth reviewing when a home is difficult to keep comfortable, when heating and cooling use is high, when rooms perform unevenly or when renovation work creates access to walls, ceilings, roofs or floors.

It may also be worth reviewing before replacing heating and cooling systems. If the building fabric is weak, new appliances may be forced to work harder than necessary.

The best timing depends on the property, climate, access, budget and broader upgrade pathway.

Should insulation be reviewed before solar or new systems?

Often, yes. Solar, batteries and efficient appliances can reduce energy use and emissions, but they do not automatically fix poor thermal comfort.

If a home loses or gains heat quickly, the heating and cooling demand may remain high. Reviewing insulation and other building fabric issues first can help ensure system upgrades are properly sized and better matched to the home.

A home energy rating can help identify whether insulation should be part of the upgrade sequence.

Renovation is often the best time to review insulation

Insulation upgrades can be easier and more cost-effective when they align with renovation works. If ceilings, walls, floors or roof areas are already being opened, the opportunity to improve insulation may be much stronger than after finishes are complete.

This is especially important for extensions, internal reconfigurations, roof replacements, recladding, floor works and major services upgrades.

For renovation pathway advice, see Existing Home Energy Rating vs Renovation Energy Assessment.

FAQs

Why is insulation important in existing homes?

Insulation is important in existing homes because it helps slow heat transfer through ceilings, roofs, walls and floors. This can improve comfort, reduce heating and cooling demand and support better energy performance.

Does a home energy rating assess insulation?

Yes. A home energy rating may consider insulation in ceilings, roofs, walls and floors where the information is available, visible, documented or able to be assessed under the relevant pathway.

What insulation should be checked in an existing home?

Useful areas to check include ceiling insulation, roof insulation, wall insulation, floor insulation, insulation around extensions or renovations, and areas where insulation may be missing, damaged or poorly installed.

Can insulation improve an existing home energy rating?

Insulation upgrades may improve the energy performance of an existing home, especially where insulation is missing, insufficient, damaged or poorly installed. The impact depends on the home, climate, construction and other building features.

Is ceiling insulation enough for an existing home?

Ceiling insulation is often important, but it may not be enough on its own. Walls, floors, windows, shading, draughts and heating or cooling systems can also affect comfort and energy performance.

Should insulation be reviewed before a renovation?

Yes. Renovation is often a good time to review insulation because walls, roofs, floors or ceilings may become accessible. Reviewing insulation early can help avoid missed opportunities and poorly sequenced upgrades.

Home Energy Rating Review

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Comparison Guide

Existing Home Energy Rating vs Renovation Energy Assessment

An existing home energy rating and a renovation energy assessment can both help improve a home, but they are not the same service.

An existing home energy rating looks at the current performance of a dwelling that has already been built. A renovation energy assessment may look at proposed changes, design options, compliance requirements and upgrade sequencing for a renovation project.

The difference matters because many homeowners begin with a simple question about comfort or running costs, then realise those answers need to be translated into practical renovation decisions.

Why this comparison matters

Renovation projects often begin with a practical problem. The home is too hot, too cold, too expensive to run, difficult to ventilate or uncomfortable in certain rooms.

A home energy rating can help explain what is happening in the current dwelling. But once renovation work is being planned, the question changes. The project team may need to know how proposed works affect performance, whether the design meets approval requirements and which upgrades should be prioritised.

That is where the distinction between rating the existing home and assessing a renovation pathway becomes important.

What is an existing home energy rating?

An existing home energy rating assesses a dwelling that has already been built. It helps describe the home’s current energy performance, comfort and upgrade potential.

The assessment may look at insulation, glazing, shading, orientation, heating and cooling, hot water, solar, batteries, ventilation and comfort concerns. It is grounded in the dwelling as it currently stands.

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

What is a renovation energy assessment?

A renovation energy assessment reviews energy performance in the context of proposed renovation works. It may look at how the design, construction scope, materials, glazing, insulation, shading, systems or layout changes affect the home’s performance.

Depending on the project, it may also support compliance advice, design coordination or upgrade sequencing. The assessment can help a project team understand what should be improved during the renovation rather than after the work has been completed.

In simple terms, a renovation energy assessment asks: how should the proposed renovation respond to the home’s energy performance goals and requirements?

The core difference: current performance vs proposed change

The simplest distinction is this: an existing home energy rating looks at the home as it is now. A renovation energy assessment looks at the renovation pathway and how proposed changes may affect performance.

An existing home rating asks: how does this dwelling currently perform?

A renovation energy assessment asks: how should the proposed works improve or respond to the home’s energy performance?

When might you use an existing home energy rating?

An existing home energy rating may be useful before renovation decisions are made, especially when the homeowner wants to understand current comfort, running costs and performance issues.

This may include:

• understanding why the home is hot or cold
• identifying weak points in the existing building fabric
• reviewing insulation, glazing and shading
• understanding whether heating and cooling systems are working too hard
• deciding whether upgrades should happen before or during renovation
• preparing for future sale, lease or disclosure expectations
• understanding the current dwelling before design work progresses

For more detail on what is measured, see What Does a Home Energy Rating Actually Measure?

When might you use a renovation energy assessment?

A renovation energy assessment may be useful once there is a proposed scope, concept design or set of upgrade decisions to review.

This may include:

• reviewing proposed glazing changes
• assessing insulation upgrades in the renovation scope
• checking whether shading is adequate
• reviewing heating and cooling strategy
• considering hot water and electrification options
• coordinating solar or battery decisions with renovation works
• supporting energy compliance for proposed works
• comparing upgrade scenarios before construction
• helping the design team avoid late-stage performance changes

This type of assessment is most useful before drawings, specifications and construction decisions are fully locked in.

Can a renovation project need both?

Yes. In many renovation projects, both forms of assessment can be useful at different stages.

An existing home energy rating can help establish the baseline: how the home performs before the renovation. A renovation energy assessment can then help apply that information to proposed works, design decisions, compliance questions and upgrade sequencing.

Used together, they can help avoid isolated upgrades that look useful on their own but do not fit the full performance strategy for the home.

Why assessment should happen before renovation decisions are locked in

Energy assessment is most useful when it happens early enough to influence the project. If the renovation design is already finalised, the opportunity to improve orientation, glazing, shading, insulation and system strategy may be limited.

Early review can help the project team understand whether comfort issues are caused by poor insulation, unshaded glazing, draughts, inefficient systems, layout problems or a combination of factors.

This can reduce the risk of spending money on upgrades that do not address the main performance problem.

Where compliance may fit into a renovation assessment

Some renovations are only about voluntary improvement. Others may trigger planning, building or energy compliance requirements depending on the location and project scope.

For example, a NSW alteration or addition may need BASIX if it meets the relevant threshold. Other projects may need NCC-related energy compliance support, such as DTS or another pathway.

This is why a renovation energy assessment may need to consider both performance improvement and compliance context. For NSW projects, see Existing Home Energy Rating vs BASIX.

Does a home energy rating tell you what to renovate?

A home energy rating can help identify performance issues and possible upgrade opportunities. It may show whether the building fabric, windows, insulation, systems or solar strategy should be reviewed.

However, turning a rating into a renovation scope usually requires design thinking. The right upgrade depends on the home, budget, timing, access, construction feasibility, comfort goals and whether the project has compliance requirements.

This is where a renovation energy assessment can help translate rating insights into practical project decisions.

Why upgrade sequencing matters

Renovation projects are one of the best times to improve energy performance because walls, roofs, windows, services or finishes may already be changing.

But the sequence matters. It may be better to improve insulation and draught sealing before upsizing heating and cooling systems. It may be better to review shading before replacing glazing. It may be better to coordinate solar and electrification with switchboard or hot water upgrades.

A renovation energy assessment can help connect these decisions so that upgrades work together rather than competing with each other.

How this differs from new-home NatHERS

A renovation energy assessment should also be separated from new-home NatHERS where the project context is different.

New-home NatHERS usually assesses a proposed residential design before construction. Existing home energy ratings assess a real dwelling that already exists. Renovation energy assessment sits between those worlds when a current home is being changed through proposed works.

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

Which pathway do you need?

The right pathway depends on the question you are trying to answer.

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

• How does this home perform now?
• Why is the dwelling uncomfortable?
• Which current features are affecting energy use?
• What performance issues should be understood before design begins?

You may need a renovation energy assessment if the question is:

• How will proposed changes affect performance?
• Which upgrades should be included in the renovation scope?
• Does the renovation need energy compliance support?
• How should insulation, glazing, shading and systems be coordinated?

When both questions matter, both pathways may need to be considered together.

Practical implications

For homeowners, the distinction helps avoid jumping straight to product decisions before understanding the home’s performance.

For designers, a renovation energy assessment can help integrate energy performance into the design process before drawings and specifications are locked in.

For builders, it can help identify where upgrades need to be incorporated into the construction scope rather than treated as optional extras later.

For consultants, the key is to clarify whether the client needs a current-state rating, proposed-work assessment, compliance support or a combination of these.

FAQs

Is an existing home energy rating the same as a renovation energy assessment?

No. An existing home energy rating assesses the current performance of a dwelling that has already been built. A renovation energy assessment may review proposed changes, compliance needs, upgrade options or design decisions for a renovation project.

When would you need an existing home energy rating?

An existing home energy rating may be useful when you want to understand how the current home performs before making upgrade, sale, lease, electrification or renovation decisions.

When would you need a renovation energy assessment?

A renovation energy assessment may be useful when proposed works need energy performance advice, design review, compliance support or upgrade sequencing before the renovation is finalised.

Can a renovation project need both?

Yes. A renovation project may benefit from an existing home energy rating to understand the current dwelling and a renovation energy assessment to review proposed changes, compliance needs and upgrade options.

Does a home energy rating tell me what to renovate?

A home energy rating can help identify performance issues and possible upgrade opportunities, but a renovation energy assessment may be needed to apply those findings to design choices, construction scope and project documentation.

Should energy assessment happen before renovation design is finished?

Yes. Energy assessment is usually most useful before renovation decisions are locked in, so insulation, glazing, shading, heating, cooling, hot water, solar and ventilation choices can be considered early.

Renovation Pathway Review

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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

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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

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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

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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

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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.

Assessment Pathway Review

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