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. NatHERS tools are currently being accredited and will soon be available for Whole of Home assessments.
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.
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 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).
It is not expected there will be an increased need to use AccuRate to do Whole of Home assessments and ratings. Once Whole of Home accreditation is finalised, assessors will be able to use any of the accredited software tools to undertake Whole of Home assessments.
NatHERS tool endorsement provides an early indication the tool is on the right track for accreditation. Importantly endorsement provides the opportunity for the NatHERS Administrator to work with the Software Tool Developer to assist with any issues that may arise during the Whole of Home tool development process.
Endorsed tools are for testing purposes only. They cannot be used to demonstrate compliance with the new NCC 2022 requirements, or produce a NatHERS Certificate or a Whole of Home rating.
Tool accreditation means tools are formally recognised as being ready to use for Whole of Home assessments and ratings for regulatory and other purposes.
For more information on the software accreditation process, which now includes Whole of Home ratings, and how to apply, see the Software Accreditation Protocol.
Sustainability Victoria has developed the FirstRate5 Whole of Home Pilot Tool and it has been endorsed by the NatHERS Administrator. The pilot tool is intended to help designers become familiar with undertaking NatHERS Whole of Home assessments, which are part of the changes to the NCC 2022.
Please note that the FirstRate5 Whole of Home Pilot Tool cannot be used to assess compliance with NCC 2022. Now that requirements for NCC 2022 are known, an updated version of the tool will be released in the next few months.
Whole of Home training was delivered to existing assessors in 2023. Two real time online modules were delivered including an overview session and a more technically focused module. Recordings of these modules and the quiz for assessment are now available online.
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 training page.
Additional software specific training will also be available as tools are accredited.
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 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 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 timeframes are ultimately a matter for each state and territory to decide. Each jurisdiction will make their own decision, keeping in mind national consistency (which helps lower industry costs) and Australia’s goal to transition to net zero emissions by 2050.
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.
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. A NatHERS endorsed Residential Efficiency Scorecard assessor undertakes training before passing an exam to become accredited. People with the appropriate level of skills and experience in performing in home assessments, but no formal qualification, can also apply for entry into the Scorecard training.
NatHERS assessors have a Certificate IV in Home Energy Efficiency and Sustainability and are accredited through a NatHERS Assessor Accreditation Organisation. 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 and 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 Existing Home assessments of existing homes.
When NatHERS Existing Home is operational, all accredited Residential Efficiency Scorecard assessors will have the opportunity to be “deemed” as a NatHERS Existing Home assessors. This will be done at the time the assessor applies for NatHERS Existing Home accreditation with an Assessor Accrediting Organisation.
The Residential Efficiency Scorecard can be used across Australia in all climate zones. As of May 2023, over 7,500 Residential Efficiency Scorecard assessments have been completed across Australia, by over 115 assessors accredited across states and territories.
The Residential Efficiency Scorecard has been piloted and trialled nationally to ensure it can rate a diverse range of buildings, appliances and locations. For tropical climates, the Residential Efficiency 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 of these locations.
Residential Efficiency Scorecard assessments incorporate features such as cross-flow 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 in the home. The Scorecard certificate suggests energy-efficient upgrade options, which are discussed during the assessment appointment.
Scorecard assessors are residential energy efficiency experts who provide households with a simple pathway to achieve their goals, such as reducing their energy costs and carbon emissions or going all-electric, while making their home more comfortable.