NatHERS and Home Energy Rating FAQs

We are an independent energy rating and building-performance practice. We provide NatHERS assessments for new and existing homes, Whole of Home ratings, and rental compliance guidance, with practical advice to improve comfort and cut running costs.

Yes. We don't sell insulation, glazing, heating, cooling or solar. That means our recommendations are about your home and your budget, not steering you toward a product we have an interest in selling.

We are based in Melbourne at 152 Elizabeth Street, working across Victoria, with team presence in New South Wales and the Australian Capital Territory.

Yes. We have team presence in NSW and the ACT for on-the-ground work, and because new home assessments are based on plans, we can complete those remotely for projects anywhere in Australia.

Yes. New home assessments are modelled from your plans and specifications, so we can carry them out remotely regardless of where the home is being built.

You can request an assessment through our website or by phone on 1300 241 149. Tell us whether it is a new build, existing home or rental property, and we'll arrange the right assessment and provide a quote.

We are among the most experienced teams in Australia at rating existing homes, and we work across new builds, renovations and rentals. Our focus is turning assessments into clear, usable plans for our clients.

New houses, townhouses and apartments, existing homes of all kinds, and rental properties preparing for minimum standards. We can also provide commercial and industrial energy assessments.

Yes. We translate the numbers into a clear plan that tells you what to do first, what it is likely to achieve, and what can wait, so your assessment turns into real comfort and savings.

We guide you on which upgrades align with available rebate and efficiency programs, so you can make the most of the support on offer when planning your works.

NatHERS, the Nationwide House Energy Rating Scheme, is Australia's national system for rating how energy-efficient a home is. It uses accredited software and CSIRO modelling to assess how well a home holds comfortable temperatures and how much energy it uses, producing a nationally consistent rating.

It measures two things: a thermal star rating out of 10 for how well the building shell holds comfortable temperatures, and a Whole of Home rating out of 100 for the home's total energy performance including major appliances and any solar.

NatHERS is an Australian Government scheme administered nationally, with the underlying modelling engine developed by the CSIRO. Assessments are carried out by independently accredited assessors using approved software.

Yes. NatHERS is a national scheme, so a rating means the same thing nationwide. Some states apply it through their own compliance pathways, but the underlying rating is consistent across the country.

The star rating measures thermal performance on a scale of 0 to 10. It reflects how much heating and cooling a home needs to stay comfortable, based on its design, orientation, insulation and glazing. A higher rating means a more comfortable, cheaper-to-run home.

A 10 star home needs almost no mechanical heating or cooling to stay comfortable year round. It represents the top of the thermal scale. Most existing homes sit much lower, which is why an assessment is useful for finding improvements.

A NatHERS rating assesses a whole home's energy performance. Appliance energy labels rate individual products like fridges or air conditioners. NatHERS looks at the building and its fixed systems together, not single appliances.

Yes. Apartments are assessed under NatHERS, with their own compliance targets for new builds. Individual units and whole buildings can both be rated.

Generally yes. A higher rating means better comfort, lower running costs and lower emissions. The value of an assessment is showing how to lift a rating cost-effectively rather than chasing stars for their own sake.

NatHERS uses validated CSIRO modelling and accredited assessors to produce consistent, reliable results. It models a full year of local climate conditions, so it reflects how a home performs in its specific location rather than a generic estimate.

For most new houses and townhouses, yes. A NatHERS assessment is the most common way to demonstrate compliance with the energy efficiency requirements of the National Construction Code, and a certificate is generally needed before a building permit is issued.

New houses and townhouses must reach a minimum 7 star thermal rating plus a Whole of Home score of at least 60 out of 100. New apartments must average 7 stars with no unit below 6, and reach a Whole of Home score of at least 50.

Since the 2022 National Construction Code update, new homes must achieve at least 7 stars for thermal performance, up from the previous 6 star minimum. A 7 star home typically needs 20 to 25 percent less heating and cooling energy than a 6 star home.

As early in the design as possible. Modelling the design before plans are finalised lets you test cost-free improvements like orientation and window placement. Fixing a shortfall after construction documents are locked in is far more expensive.

Floor plans, elevations and sections, a window schedule, and specifications for insulation, glazing and major fixed appliances. The more complete the documentation, the more accurate the rating.

It is the official document showing your star rating, Whole of Home score, modelled heating and cooling loads, and climate zone. Your building surveyor or certifier uses it as evidence of energy efficiency compliance.

Yes. Seven stars is a minimum, not a maximum. Many homes are designed to 8 stars or beyond for greater comfort and lower bills, and the extra performance is usually most affordable when planned from the start.

Major renovations and extensions can trigger a NatHERS assessment, depending on the scope of work and your state or territory rules. If you are significantly altering the building shell, it is worth checking early.

An assessor shows you the most cost-effective changes to get there, such as upgrading glazing, adding insulation, adjusting window sizes or improving shading. Caught early, most homes reach compliance with minor design adjustments.

No. NCC 2025 introduced no new residential energy efficiency measures, and further residential changes have been paused, so the 7 star and Whole of Home framework remains the standard for the foreseeable future.

Yes. New home assessments are based on your plans and specifications, so they can be completed remotely from your documentation, wherever the project is located in Australia.

In NSW, thermal performance is assessed through BASIX rather than NatHERS directly, with targets aligned to the 7 star standard. The compliance pathway differs, but the underlying performance outcome is comparable.

Yes. NatHERS has expanded to rate homes that are already built. An accredited assessor visits, records how the home is constructed and equipped, and produces a star rating and a Whole of Home rating along with practical improvement advice.

No. The assessor gathers everything needed during the home visit, so plans are not required. Any plans or renovation records you do have can help confirm hard-to-see features, but they are not essential.

The assessor records construction and materials, insulation, windows and glazing, shading, orientation, ventilation, and your heating, cooling, hot water and any solar. The visit is non-invasive and usually takes a couple of hours.

A new home assessment models a design from plans before it is built. An existing home assessment captures the home as it actually is now, through a site visit, including every renovation and upgrade made over the years.

Because it turns guesswork into a plan. It shows where your home wastes energy so upgrades are targeted, and it adds credibility when selling, leasing or applying for green finance. It is useful whether you stay for decades or sell next year.

Yes. It pinpoints where comfort and energy are lost, so upgrades like insulation, sealing, glazing or efficient electric appliances can be prioritised by payback rather than guesswork.

After the home visit, the report and certificate are usually ready within a few business days. If you are working to a deadline for a sale, loan or renovation, let your assessor know.

Not at this stage. It is currently voluntary, but it is being requested more often for property sales, renovations and green finance, and governments are trialling energy rating disclosure at sale and lease.

A thermal star rating out of 10, a Whole of Home rating out of 100, an official NatHERS certificate, and a set of tailored, prioritised recommendations for improving your home's performance.

Generally yes, or someone with access to the property. The assessor needs to see inside rooms, the roof space where accessible, and the heating, cooling and hot water systems to record accurate details.

Clear access to the roof space hatch if possible, and have any information on insulation, window types, and the age and type of your heating, cooling and hot water systems. It helps the assessor work efficiently.

An assessment does not need the property owner's involvement. Renters interested in their home's performance are best to raise it with the rental provider or manager if they are concerned.

It is the part of a NatHERS assessment that scores your home's total energy use out of 100. It combines the energy used by major fixed appliances with the energy generated by any solar, giving a single measure of efficiency and running cost.

Heating and cooling, hot water, lighting, and pool or spa pumps, offset by rooftop solar generation and battery storage. Cooking and plug-in appliances may appear on the certificate for information.

Higher is better. Below 40 is a poor performer, 60 is the compliance minimum for a new house, and 100 represents a net zero energy home with low or no energy bills. Scores above 100 are possible.

Yes. A score above 100 means the home generates more energy than it uses across the year, typically through a well-sized solar system, and exports the surplus. These homes usually have very low or no net energy bills.

The star rating out of 10 measures the building shell. The Whole of Home rating out of 100 adds appliances and subtracts solar. The star rating is about how the home is built, the Whole of Home rating is about how it is run.

Yes, directly. Rooftop solar generation is subtracted from the energy your home draws, so adding solar is one of the most effective ways to raise the score.

It can. A battery stores solar energy for use after dark, increasing how much of your own generation you use rather than drawing from the grid, which supports a higher score.

Efficient electric appliances like reverse-cycle air conditioning and heat pump hot water use less energy than older gas or electric resistive systems, and they pair well with solar. Combining them is the clearest route to a high score.

Yes, and often they do. Two homes with identical shells will score differently if one runs efficient electric appliances and solar while the other runs old, inefficient systems. Appliances and generation separate them.

The highest-impact changes are usually heat pump hot water, efficient reverse-cycle heating and cooling, rooftop solar and battery storage, supported by efficient lighting. An assessment shows which matter most for your home.

For new homes and major renovations it is part of National Construction Code compliance. For existing homes it is voluntary, though increasingly valued for planning upgrades, selling, leasing and green finance.

Generally yes. The score reflects how much energy your home draws after solar, so a higher score usually means lower running costs and emissions. A home at or above 100 will have very low or no net energy bills.

For a new home, an assessor models your plans in accredited software. For an existing home, an assessor visits and records the home's details. Both are calculated using CSIRO-based software to produce your ratings and recommendations.

Accredited tools such as AccuRate, FirstRate5 and BERSPro for new homes, and AccuRate Enterprise for existing homes. All are built on the CSIRO Chenath engine and produce nationally consistent results.

Only an accredited NatHERS assessor. Accreditation involves training and ongoing professional development to ensure ratings are accurate and consistent. It is always worth confirming your assessor is accredited before booking.

An existing home visit usually takes a couple of hours, with the report following within a few business days. A new home assessment depends on the complexity of the plans. Ask for a timeframe when you request a quote.

Australia has many climate zones, and the same home performs differently in each. NatHERS software automatically applies your local climate data, so the rating reflects real conditions at your address.

The Chenath engine is the CSIRO-developed calculation core that underpins accredited NatHERS software. It models how heat moves through a building across a full year to produce the thermal star rating.

Yes. A good assessment is not just a number. You receive practical, prioritised recommendations on the changes that would lift your home's performance most, tailored to your home and budget.

Often yes. A rating that reflects your home accurately can support renovation decisions, property listings and green finance applications, as long as no major changes are made to the home afterwards.

A climate zone is a defined area with similar weather patterns used in energy modelling. Your assessor identifies your zone from your address, so you do not need to look it up yourself.

You receive an official NatHERS certificate, typically as a digital document, showing your ratings and key modelling details. It can be saved, printed and shared with your certifier, agent or lender as needed.

It depends on the size and complexity of the home and whether it is a new build or existing home. The best approach is to request a clear, fixed quote up front so there are no surprises.

The size and design complexity of the home, whether it is a new build modelled from plans or an existing home requiring a visit, the location, and the number of dwellings for multi-unit projects, some regions also carry rebates on assessments.

For most homes, yes. It turns vague concerns about comfort and bills into a clear plan, helps you spend upgrade money in the right order, and can support compliance, sale and finance, often paying for itself.

Evidence suggests so. Energy-efficient homes in Melbourne have been shown to command a significant price premium over comparable inefficient homes, reflecting growing buyer demand for comfort and low running costs.

Many do, through lower energy bills and improved comfort. An assessment prioritises upgrades by payback, so you can start with the changes that recover their cost fastest.

Often yes, depending on your state and the measure. Programs such as the Victorian Energy Upgrades scheme offer discounts on efficient heating, hot water, draught proofing and more. Always check current program details.

It depends on your circumstances, for example whether the property is an investment. Tax treatment varies, so check with a registered tax professional rather than assuming. We are not tax advisers.

Yes. A higher rating means the home needs less energy for comfort and runs more efficiently, which lowers ongoing bills. The size of the saving depends on your starting point and how you use the home.

State-based. Residential tenancy law sits with each state and territory, so minimum rental energy standards and their timing differ across Australia. There is no single national rental standard.

They phase in from 1 March 2027, with further requirements from 1 July 2027 and a final cooling requirement for all rentals from 1 July 2030. Many requirements are triggered at the start of a new or periodic lease.

Ceiling insulation where none exists, efficient electric heating and hot water as systems reach end of life, efficient cooling in the main living area, draught proofing of doors, windows and wall vents, and 4-star showerheads, phased across the deadlines.

From 1 March 2027, at the start of a new or periodic lease, ceiling spaces with no insulation must be insulated to R5.0 by an accredited installer. Ceiling spaces with some existing insulation are treated differently.

Not immediately. From 1 March 2027, when an existing heating or hot water system reaches end of life, it must be replaced with an efficient electric system such as a reverse-cycle unit or a heat pump.

Efficient cooling in the main living area is required from 1 March 2027 at the start of a new or periodic lease, and from 1 July 2030 it applies to all rental properties regardless of lease timing.

From 1 July 2027, at the start of a new or periodic lease, external doors, windows and wall vents must be draught proofed to reduce unwanted heat loss in winter and heat gain in summer.

Yes. Exemptions can apply where compliance is impractical or unreasonably costly, such as apartments with shared ceiling space or centralised systems, and where heritage or design constraints apply. Exemptions vary by standard.

Yes. The Victorian Energy Upgrades program offers discounts on measures like reverse-cycle heating, heat pump hot water, draught proofing and showerheads, and solar rebates and loans are available to eligible rental providers.

Rental providers are legally required to meet minimum standards. Non-compliance can lead to enforcement action and disputes through the relevant tribunal. Preparing ahead of each deadline is the simplest way to avoid problems.

Each has its own rules. The ACT has introduced a minimum ceiling insulation standard for rentals, and NSW is progressing its own reforms. The specifics differ from Victoria, so check the requirements for the property's location.

The new standards are effectively an efficiency and electrification checklist. A NatHERS assessment maps your property against it, shows where it stands, and sets out the upgrades that deliver the most comfort and savings.

Now. With the first deadlines in 2027 and many triggered by a new lease, getting an assessment and plan in place early gives time to budget, access support, and avoid a rush as the dates approach.

It varies by home, but the biggest levers are usually ceiling insulation, draught sealing, glazing improvements, efficient electric heating and cooling, heat pump hot water, and rooftop solar. An assessment shows your priorities.

Yes. Ceiling, wall and floor insulation is often the single biggest influence on an older home's rating, because it reduces how much heat the home loses in winter and gains in summer.

More than people expect. Sealing gaps around doors, windows, floors and vents stops conditioned air escaping. It is usually low cost and delivers a noticeable improvement in comfort and bills.

It can be, especially for homes with large or unshaded windows. Glazing upgrades reduce heat loss and gain through windows, though shading and orientation also matter and are sometimes cheaper wins.

Electrification means replacing gas appliances with efficient electric ones, such as swapping gas heating for a reverse-cycle system and gas hot water for a heat pump. Paired with solar, it typically lowers running costs and emissions.

Efficient electric appliances generally cost less to run than gas equivalents, work well with rooftop solar, and reduce emissions. Many homeowners electrify gradually as gas appliances reach end of life.

A heat pump hot water system uses electricity to move heat from the air into the water tank, rather than generating heat directly. It is far more efficient than electric resistive or gas hot water, making it a high-impact upgrade.

Yes. A modern reverse-cycle system is one of the most efficient ways to heat and cool a home, delivering several units of heating or cooling for each unit of electricity used.

Solar reduces the energy you draw from the grid and lifts your Whole of Home score. Whether it suits you depends on your roof, usage and budget. An assessment helps you weigh it against other upgrades.

Usually shell first, then systems, then generation: insulation and sealing, then efficient electric heating, cooling and hot water, then solar. An assessment tailors this order to your specific home and budget.

Yes. Beyond saving money, efficiency upgrades reduce draughts, cold spots and overheating, so the home stays at a comfortable temperature more easily across the year.

They can help. Better insulation, sealing and ventilation reduce the cold surfaces and trapped moisture that lead to condensation and mould, though severe moisture problems may need specialist advice.

It can. As energy rating disclosure becomes more common at sale, a strong rating reassures buyers about comfort and running costs, and can help an efficient home stand out in a competitive listing.

Governments are trialling the disclosure of home energy ratings at the point of sale and lease, starting in some states. It is not universal yet, but the direction is toward greater disclosure over time.

Yes. A rating gives buyers insight into likely running costs and comfort before they commit, and highlights what upgrades a home might need, which can inform both the decision and the offer.

Green home finance refers to loans and lending incentives that reward energy-efficient homes, sometimes with discounted rates or extra borrowing capacity for efficiency upgrades. Lenders increasingly use energy performance to assess eligibility.

Increasingly, yes. A number of banks use home energy performance to offer discounted green home loans, so a NatHERS rating may support a better lending outcome. Always check the specific lender's requirements.

Some lenders offer more favourable terms or dedicated green loan products for efficient homes or for financing upgrades. Availability and conditions vary by lender, so it is worth comparing options.

Efficiency is increasingly valued by buyers, and energy-efficient homes have been shown to command price premiums in some markets. A rating provides evidence of that efficiency to support a sale.

Yes. A strong NatHERS rating can be referenced in marketing to highlight comfort and low running costs, which appeal to buyers and renters who are increasingly conscious of energy bills.

An efficient home holds a comfortable temperature more easily, with fewer cold spots in winter and less overheating in summer, and it does so using less energy. Comfort and efficiency go hand in hand.

A well-insulated, sealed and ventilated home is easier to keep at healthy temperatures and can reduce damp and mould, which supports better respiratory health. Extreme indoor temperatures carry real health risks.

Condensation forms when moist air meets cold surfaces, common in poorly insulated, poorly ventilated homes. Over time it can lead to mould. Insulation, sealing and good ventilation reduce the risk.

Insulation slows heat moving into the home, keeping it cooler for longer during hot weather and reducing the work your cooling has to do. It is just as valuable in summer as in winter.

Thermal comfort is the condition where occupants feel neither too hot nor too cold. A home with a good thermal rating achieves it more of the time with less mechanical heating and cooling.

Yes. A thermally efficient home stays cooler for longer during extreme heat, which improves comfort and safety and reduces reliance on air conditioning when energy demand and costs peak.

More efficient homes use less energy and produce fewer emissions, supporting national targets like net zero. Improving the existing housing stock is a significant part of reducing household emissions.

Yes. A home that needs less energy for comfort is less exposed to energy price rises. Efficiency and on-site solar both reduce how much energy you need to buy.

Your Scorecard certificate still describes your home's performance at the time it was assessed, so the information remains helpful. However, Scorecard and NatHERS are calculated differently and are not interchangeable. For a current NatHERS rating you would need a new assessment.

Home energy rating has been consolidated under NatHERS, the national scheme, so that existing homes are rated on the same nationally consistent basis as new homes. It is a step toward a single, comparable measure of home performance.

NatHERS is now the national framework for rating both new and existing homes. Earlier or state-specific tools are being aligned or superseded so that ratings mean the same thing across the country.