FAQs

In 2019, Energy Ministers agreed the Trajectory for Low Energy Buildings, a national plan that aims to achieve zero energy (and carbon) ready commercial and residential buildings in Australia.

The Trajectory proposed that NatHERS be expanded to offer nationally accredited Whole of Home tools to support new requirements in the National Construction Code (NCC 2022). See the NatHERS software page for the latest on Whole of Home accreditation.

Updates to NCC 2022 are being adopted by states and territories. They require new homes meet 7 stars and also a Whole of Home rating of 60 (out of 100). New apartments will have to meet an average rating of 7 stars for all apartments (with no apartment under 6 stars), and a Whole of Home rating of 50 (out of 100).

For the last 30 years NatHERS has rated the shell of a new home to provide a streamlined and cost-effective approach to meet or beat the new National Construction Code energy efficiency requirements. In 2022 the National Construction Code added the new Whole of Home rating which allows for a more holistic rating that captures appliances within the home.

By capturing more of the energy a home uses, the rating better informs home owners and builders to make energy efficient choices in building and selecting appliances for their homes. The addition of the Whole of Home rating will help lower energy use and bills for households across Australia, while also ensuring comfortable and resilient homes for the future. This expansion is supporting the reliability of the energy grid, and a range of initiatives, such as the finance sector using NatHERS to underpin green loan products. 

A Whole of Home assessment for regulatory purposes must include an assessment of the following appliances:

• hot water, heating and cooling systems
• pool and spa equipment
• lighting and plug in appliances
• solar energy generated onsite and battery storage 

The NatHERS Technical Note provides information on what to do if the appliance type is unknown at the time of assessment.

The Whole of Home rating is based on the National Construction Code's energy value metric. The energy value includes the estimated cost of the energy the home uses, the estimated cost to the energy network and the cost of carbon emissions that are a result of the home’s energy use.

The energy use is based on assessment of the home’s thermal performance, appliances and offsets provided by any onsite renewable energy generation and storage (e.g. solar PV and battery).

The Whole of Home rating scale ranges from 0 to 100 – a poor energy performing home would be under 40, while a score of 100 is a net zero energy value home. A rating over 100 is possible where the home is producing more energy than it uses. Ratings at 100 or above mean the home will have low or no energy bills.

The new National Construction Code (NCC 2022) residential energy efficiency standards mean new houses and apartments will need to meet minimum thermal performance star ratings (out of ten stars) as well as Whole of Home ratings (0-100).

Under NCC 2022 new houses will have to meet 7 stars and a Whole of Home rating of 60 (out of 100). New apartments will have to meet an average rating of 7 stars for all apartments (with no apartment under 6 stars), and a Whole of Home rating of 50 (out of 100).

Information on which tools have been accredited for Whole of Home ratings can be found on the  NatHERS Software page.

Assessors who want to become certified for Whole of Home must complete the technical training and pass the quiz. See the NatHERS website and YouTube channel for Recordings of the sessions and more detail. 

Commercial tool providers are also running independent training covering various aspects of their updated tools. The training is free for registered users. Read more about this training on the NatHERS assessor toolkit training page.  

Additional software specific demonstrations are available for BERS Pro, Hero, and FirstRate5. Recordings of these online sessions are available on the NatHERS YouTube channel and via tool providers and AAOs. 

For new assessors, Whole of Home training will be delivered through the Certificate IV training ‘Using Accredited Software’. Read more on the becoming an assessor section of the Assessor Toolkit webpage on NatHERS.gov.au.  

There are four accredited software tools, each with different user interfaces and functions. You will need to decide which software tool best meets your needs. For information on using accredited software, see the Assessor Toolkit page. 

For a demonstration of a Whole of Home assessment see this video. 

Additional details on the Whole of Home National Assessor Accreditation and Training Strategy can be found here. 

Accurate Home is only free for assessors who are currently licensed to use AccuRate Sustainability, otherwise licence fees will apply to use AccuRate Home. Email the Energy Inspection team for more information.

NatHERS can be used to assess the thermal performance of all individual units within apartments (Class 2 buildings), providing a star rating out of 10.

It can also be used to comply with the new National Construction Code (NCC 2022) Whole of Home requirements where apartments have decentralised hot water and space conditioning systems.

NatHERS currently does not offer a Whole of Home option for apartments with centralised services, but a proposal has been developed and will soon be available for public comment.

The NatHERS Administrator expects that tools in the scheme will be able to assess Class 2 buildings with centralised services from next year (2025).  

If you are assessing the Whole of Home compliance of apartments with centralised services, you can use the alternative pathways in NCC 2022. For example, for apartments with centralised hot water systems, you can use NCC 2022 Volume 1 Verification Method J1V5, also known as Verification Using a Reference Building (VURB), or another Performance Solution. 

A combination of approaches can be used to demonstrate compliance – for example, using NatHERS to demonstrate the thermal performance requirements and VURB to demonstrate Whole of Home compliance.  

Helpful resources for assessors include the Australian Building Code Board’s recently released Apartment Energy Efficiency Handbook and the Housing Energy Efficiency Handbook, which provide guidance on the new requirements for apartment buildings.

The question has been raised about including "future work" in Whole of Home assessments, in situations where building plans indicate that there will be PV installed (e.g. trusses on the roof) or a swimming pool (e.g. plumbing in situ for future installation) by the owner post-handover.

As per the NatHERS Technical Note, the NatHERS certificate must match the design documentation (clause 3.3). 

Any future work to be installed post-handover/occupancy certificate must be:

• recorded on the approved construction drawings/design documentation for the assessor to use, and
• approved by the appropriate authority, generally the building certifier, with evidence of this provided to the assessor by the architect/owner/builder.

No further comments are deemed to be required in the additional notes section of the certificate.

All supporting information that informs a decision must be kept with the plans and documentation.

NatHERS has updated the climate files to provide more up-to-date climate data that is more consistent, more representative of recent climate and provides better accuracy in the assessment of energy use in residential homes. NatHERS Climate Files have not been updated since 2005. The new climate files were created from high quality climate data collected from 1990 to the end of 2016. More information is available here. 

The star bands have been re-calibrated because of the introduction of the updated climate files to NatHERS. This is to limit the impact of change, maintain the integrity of the scheme and avoid burdensome adjustment for industry. The star band re-calibration was based on limiting change to star ratings to an ‘average of zero’ for building types in a climate’s star band. More information is available here.

The updated climate files and re-calibrated star bands could mean that there will be a small change to individual house energy ratings depending on house design, building construction and climate zone. More information is available here.

Thermal bridging can significantly reduce the effectiveness of insulation if not accounted for. Thermal bridging is where a material acts as a bridge to transfer heat or cold across the material into or out of a home. For example, an insulated steel wall frame, directly connected to the exterior cladding forms a bridge, which allows heat to travel through the steel frame more readily than the surrounding insulation. NatHERS has introduced thermal bridging to regulatory ratings to align with the other compliance pathways in the National Construction Code. More information is available here.  

The National Construction Code and NatHERS software considers the impact of thermal bridging in steel framed houses.  The impact of introducing this approach to thermal bridging is expected to be up to 0.5 of a star rating depending on the design of a home. More information is available here.

The NatHERS thermal star rating and the Whole of Home rating can both be used to meet compliance with the new NCC energy efficiency provisions.

The new minimum thermal star rating requirements will be the equivalent of 7-stars on the NatHERS scale, with allowances for outdoor living area and/or ceiling fans in NCC climate zones 1 and 2. 

The NatHERS thermal star rating can be used as a Deemed-to-Satisfy method H6D2 to meet the thermal performance requirements H6P1 by complying with Specification 42 (S42C2) and S42C4(1) of NCC Volume Two (Class 1 buildings) and clauses J3D3 of NCC Volume One (apartments).

The NatHERS thermal star rating and the Whole of Home rating will both be used to meet compliance with the new NCC energy efficiency provisions.

The Whole of Home rating can be used as one way to demonstrate compliance with the energy use requirements detailed in Specification 42 (S42C3) of NCC Volume Two (Class 1 buildings) and clause J3D15 of NCC Volume One (apartments).

The minimum Whole of Home rating requirements are:

• 50 for apartments (Class 2 sole-occupancy units and Class 4 parts of buildings)
• 60 for houses (Class 1 buildings)

Note, variations and additions to the NCC energy efficiency requirements may apply in some states and territories.

When conducting a NatHERS energy assessment, the star rating is based on the total amount of energy predicted to be needed to keep that house comfortable. That total is broken down into the amount required for heating and cooling and is displayed on the NatHERS Certificate as well as the star rating. 

To meet NCC requirements, a house design must meet the minimum energy requirements for a given location (the total energy use) and must not exceed either the heating or cooling load limits for that star band and location. The limits are designed to exclude the worst 5% of houses at a given location, with respect to the amount of energy used for heating and cooling. 

The ABCB Standard that sets out the NatHERS heating and cooling load limits was updated in NCC 2022, to reflect the changes to NatHERS climate files and the associated changes to star bands. These updates mean the amount of energy corresponding to each star band has changed, so the accepted split of that energy into heating and cooling limits must also be adjusted. 

The split loads were updated using the same principle, whereby they exclude the worst 5% of houses, based on the historical data recorded in the Australian Housing Data portal. 

Implementation of NCC 2022 energy efficiency changes are ultimately a matter for each state and territory.

In NSW, BASIX adopted a 7-star minimum in late 2023.The new requirements for both 7-star and Whole of Home were introduced in the ACT in January 2024. Victoria and Queensland will introduce the updates from 1 May 2024, and South Australia from 1 October 2024.

You can check your jurisdiction’s building authority for local advice on transitional provisions

For 30 years, NatHERS has provided energy performance ratings for new Australian homes, making them more energy efficient and comfortable to live in.

NatHERS is expanding and by mid-2025 will have the ability to provide energy performance ratings for existing homes. Assessments will be performed by a trained and accredited assessor visiting the home to gather the data. Building plans and specifications are not needed.

Currently, the Residential Efficiency Scorecard offers NatHERS endorsed energy ratings for existing homes. The Scorecard is administered by the Victorian Government on behalf of all Australian governments.

NatHERS assessments will be different for existing homes and new homes.

Unlike assessments for new homes, NatHERS assessments for existing homes will require a visit to the home. They will not require detailed architectural drawings and specifications. However, where detailed house drawings and evidence of what products and equipment have been installed are available, it is possible for an existing home to be rated in the same way as a new home.

While NatHERS ratings will be consistent and comparable for new and existing homes, there may be slight differences in the result. This is because there is likely to be less information available for existing homes about the construction and the equipment installed.

The purpose of NatHERS assessments for existing homes will be different to assessments for new homes. Existing home assessments will be designed for householders who wish to learn more about their existing home’s energy performance, cost, greenhouse gas emissions and comfort, or wish to disclose the energy performance of the home when selling or renting. These assessments will be designed to guide decisions for energy upgrades that can improve comfort, energy efficiency and minimise running costs and greenhouse gas emissions.

The Residential Efficiency Scorecard rates your home's energy use and comfort, and provides tailored recommendations for improvements.

A Scorecard assessment will help you make the best choices by providing targeted information to ensure that any money you spend on upgrades will lead to a cheaper to run, more comfortable home.

Assessors provide a Scorecard certificate with a star rating out of 10 indicating the cost to run the fixed appliances in the home, ratings for comfort, and the main factors influencing energy consumption in the home. The Scorecard certificate suggests energy-efficient upgrade options, which are discussed during the assessment appointment.

Scorecard assessors are accredited by government. They have existing qualifications and/or skills and experience and undertake training before passing an exam to become accredited. Assessors are not employed by government and set their own fees. 

The Scorecard program, including the assessment tool, assessor training and assessor accreditation, is delivered by the Victorian Government on behalf of all Australian governments. The Scorecard is endorsed by NatHERS.

The Residential Efficiency Scorecard (assessment tool, training and accreditation and quality assurance) was endorsed as meeting the criteria and standards set by the NatHERS Steering Committee. The NatHERS Steering Committee is a government body that oversees NatHERS.

The Residential Efficiency Scorecard submitted documentary evidence for each criterion. The NatHERS Administrator assessed the evidence and the NatHERS Steering Committee endorsed the Residential Efficiency Scorecard as having met the requirements.

NatHERS endorsement means the tool, training and accreditation demonstrate alignment with what NatHERS assessments for existing homes are expected to require in the future. It is an early indication these products demonstrate the ability to obtain full NatHERS accreditation in the future, although some amendments are expected as the NatHERS requirements for existing homes are agreed and finalised.

To be accredited under NatHERS, the Scorecard will need to meet all the requirements for NatHERS for existing homes. These requirements are currently under development.

No, Scorecard and NatHERS have related but different requirements for becoming an accredited assessor.

A Residential Efficiency Scorecard assessor is required to have a minimum of 4 units from a relevant Certificate IV, or an equivalent level of skills and experience. Scorecard assessors must undertake training and pass an exam to become accredited. Scorecard assessors are accredited directly by the scorecard program.

NatHERS assessors have a Certificate IV and are accredited through a NatHERS Assessor Accreditation Organisations. NatHERS assessors use floor plans and building specifications to assess and provide an energy rating for a new home or major renovation at the planning stage. A home visit is not required. Currently, NatHERS assessors have the option of undertaking additional training to become a Residential Efficiency Scorecard assessor so they can also carry out assessments on existing homes.

Find out more about the Residential Efficiency Scorecard. 

Scorecard can be used across Australia in all climate zones. As of December 2023, over 8,700 Residential Efficiency Scorecard assessments have been completed across Australia, with over 125 assessors accredited across all states and territories.

Scorecard has been piloted and trialled nationally to ensure it can rate a diverse range of buildings, appliances, and locations. For tropical climates, Scorecard has been tested in the field by skilled assessors with local knowledge in locations including Cairns, Broome, Darwin, and Townsville. It was found to be suitable for use in all these locations.

Scorecard assessments incorporate features such as crossflow ventilation and ceiling fans, which are particularly important in tropical climates. Assessments in temperate climates consider features important to manage both hot and cold weather extremes.

The Residential Efficiency Scorecard enables energy performance assessments to be conducted on existing homes of any age or location, without the need for plans or specifications.

Accredited assessors use the government supported Scorecard tool. Assessors provide a certificate with a star rating out of 10 indicating the cost to run the fixed appliances in the home, ratings for comfort and the main factors influencing energy consumption. The Scorecard certificate suggests energy efficient upgrade options, which are discussed during the assessment appointment.

Scorecard assessors are energy efficiency experts who help Australian householders reduce their energy bills, make their home more comfortable and decrease their carbon emissions.

The National Scorecard tool, training, accreditation and quality checks are being delivered by the Victorian government across Australia, on behalf of all Australian governments.