Poorly designed and constructed homes are wasting energy and costing householders. NatHERS is helping avoid this waste by guiding better design and construction of homes, reducing energy demand and household energy bills now, and into the future.
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 enable verification of requirements in the National Construction Code.
The Whole of Home rating is based on the NCC’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 10, 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 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).
An updated version of the NatHERS benchmark software (AccuRate Home) is available now, with more tools expected to be accredited in the coming months.
NatHERS has endorsed the FirstRate5 Whole of Home Pilot Tool to provide an early indication of NatHERS accredited tools that may be available in the future. Endorsement means the tool includes all the key modules for a Whole of Home assessment and is on the right track for accreditation. More information about the FirstRate5 Whole of Home Tool is available here.
HERO Software, BERS Pro and FirstRate5 have all released endorsed beta versions of their thermal tools which can be used to test house designs without thermal bridging.
Endorsed tools demonstrate what is possible for accredited tools, by providing an indication of the look, feel and usability. Endorsed tools are for testing purposes only. They do not produce a NatHERS Certificate or Whole of Home rating that can be used to demonstrate compliance with the new NCC 2022 requirements.
Assessors will be able to use a range of accredited software to undertake Whole of Home assessments. It is not expected there will be an increased need to use AccuRate to do Whole of Home assessments and ratings.
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.
If you are an existing accredited assessor you will need to undertake Continuing Professional Development (CPD) to receive a ‘Statement of Completion’ recognising a minimum of 2 units in NatHERS Whole of Home assessments.
A number of CPD units on Whole of Home are currently being developed. An overview unit covering background and key components, and a unit focused on the Technical Note and Guidance Note will be available from early to mid-2023. Software specific training will be available after tools become accredited.
A number of Continuing Professional Development (CPD) units on Whole of Home are currently being developed. These will provide assessors with all the information and guidance required to undertake Whole of Home assessments.
An overview unit covering background and key components, and a unit focused on the Technical Note and Guidance Note will be available from late 2022. Software specific training will be available after tools become accredited. Software specific training will be available after tools become accredited.
If you are a new assessor you will need to complete a relevant Certificate IV qualification. The Certificate IV is currently being reviewed for its suitability for Whole of Home. If you complete a Certificate IV that doesn’t cover Whole of Home you will need to also complete the CPD units. The NatHERS website will be updated with detail of Certificate IV courses that include Whole of Home as they are updated.
NatHERS has updated the climate files to provide a more up-to-date climate data set that is more consistent 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 (in this case steel framing) acts as a bridge to transfer heat or cold across the material into a home. For example, an insulated steel wall frame, directly connected to the exterior cladding could form a thermal bridge, allowing the heat to travel through the steel frame more readily than the surrounding insulation. NatHERS will introduce 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 also 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 star 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 one way to meet compliance with the thermal performance requirements detailed in Specification 42 (S42C2) 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 star 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 (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 split heating and cooling load limits will be 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 is changing, so the accepted split of that energy into heating and cooling limits must also be adjusted.
The split loads will be updated using the same principle, whereby they will 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.
You can check with your jurisdiction’s building authority for local advice on transitional provisions.
For almost 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 will soon have the ability to include In Home energy performance ratings for established homes. In Home assessments will be performed by a trained and accredited assessor visiting the home to gather the data. Building plans and specifications are not needed.
The Residential Efficiency Scorecard is already offering this type of in-home rating. NatHERS is working with the Scorecard team to develop elements of NatHERS In Home. The NatHERS In Home Scheme will launch in mid-2023. It is anticipated that the first NatHERS accredited In Home tool will be the Residential Efficiency Scorecard. After mid-2023, the market will be opened to other tools to seek accreditation under NatHERS In Home.
The Commonwealth, state and territory governments are extending NatHERS to include Whole of Home and In Home energy ratings. Each assessment suits a different need.
NatHERS In Home assessments are designed for householders with an established home who wish to learn more about their home’s energy performance, cost, greenhouse gas emissions or comfort, or which to disclose the energy of the home when selling. These assessments rate the home by collecting information from a visit to the home. These assessments are designed to guide decisions for energy upgrades that can improve comfort, energy efficiency and minimise running costs and greenhouse gas emissions.
NatHERS Whole of Home assessments are an extension of the current NatHERS (thermal) assessment of new homes and renovations. These assessments will incorporate major appliances such as heating and cooling, hot water systems, lighting, pool/spa pumps and on-site energy generation. No home visit is required as these assessments use plans and specifications to assess the home. These assessments can be used for assessing the designs of new builds and major renovations and are one pathway to comply with the National Construction Code energy efficiency provisions.
A Residential Efficiency Scorecard rating 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.
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.
Currently endorsed by NatHERS, the Residential Efficiency Scorecard tool is expected to be the first accredited tool under NatHERS In Home. Until this occurs, all elements of the Scorecard program, including the assessment tool, assessor training and assessor accreditation, will continue to be delivered by the Victorian Government on behalf of all Australian governments.
'NatHERS endorsed' means the tool, training and accreditation aligns with what NatHERS In Home assessments will require in the future, although some amendments are expected as requirements are agreed and finalised.
The Residential Efficiency Scorecard (assessment tool, training and accreditation and quality assurance) was endorsed by 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.
Currently endorsed by NatHERS, the Residential Efficiency Scorecard tool is expected to commence the NatHERS accreditation process in 2023. Until this occurs, all elements of the Residential Efficiency Scorecard, including the assessment tool, training and assessor accreditation, will continue to be delivered by the Victorian Government on behalf of all Australian governments.
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 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 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 In Home assessments of existing homes.
When NatHERS In Home is operational, all accredited Residential Efficiency Scorecard assessors will have the opportunity to be “deemed” as a NatHERS In Home assessors. This will be done at the time the assessor applies for NatHERS In Home accreditation with an Assessor Accrediting Organisation.
The long term goal is for NatHERS design rating for a new home to correlate with an in-home rating for the same home once built.
Once the NatHERS In Home processes (such as tool accreditation, Assessor Accrediting Organisations accreditation, In Home Certificate, etc.) are finalised, data will be collated and the correlation evaluated. Depending on the results, further refinement will be undertaken to achieve correlation.
It should be expected that a 100% correlation may not be achieved. This is because of the greater quantity and detail of information available for a NatHERS assessment for a new home, which includes detailed architectural drawings and specifications. When assessing an older, established home, design plans are often not available. Additionally a home may have undergone renovation or appliances altered since construction, resulting in unreliable design drawings and specifications.
NatHERS In Home assessments and the Residential Efficiency Scorecard can be used across Australian in all climate zones. Currently over 6,000 Residential Efficiency Scorecard assessments have been completed across Australia, with over 100 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 conducted in tropical areas consider important features such as cross-flow ventilation and ceiling fans. 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 established homes of any age or location, without the need for plans or specifications.
Accredited assessors use the government supported Residential Efficiency 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.
Accredited Residential Efficiency Scorecard assessors can also assist home owners to better understand their home’s energy performance and provide expert advice on steps they can take to improve the comfort of their home and reduce their bills. The assessment certificate provides options on simple, energy-efficient upgrades which are discussed during the assessment appointment.
The National Scorecard tool, training, accreditation and quality checks will initially be delivered by the Victorian government across Australia, on behalf of all Australian governments.
Over time there will be further alignment of the National Scorecard program with NatHERS processes including the transitioning of training and accreditation to Registered Training Organisations and Assessor Accrediting Organisations.