Frequently Asked Questions (FAQ)
Q: Why does Council require a Thermal Performance Assessment to be carried out on my house design?
Q: What is a Thermal Performance Assessment?
Q: How is a Thermal Performance Assessment done?
Q: How can I find an Accredited Assessor to carry out a Thermal Performance Assessment?
Q: How much does a Thermal Performance Assessment Cost?
Q: I am completing a BASIX Certificate in NSW. Where can I get some assistance?
Q: How do I become an Accredited Thermal Performance Assessor?
Q: Why does Council require a Thermal Performance Assessment to be carried out on my house design?
A: All states in Australia require new homes to meet minimum thermal performance standards. In other words, the home must be designed to remain at a comfortable temperature without the need for excessive heating or cooling. These requirements are designed to reduce the amount of fossil fuels burned to produce energy for homes, thereby reducing Australia’s greenhouse gas emissions.
In all states and territories except NSW, the Building Code of Australia (BCA) sets these requirements. In NSW, the Building Sustainability Index (BASIX) overrides BCA requirements and sets the required levels of performance.
Under the BCA, all dwellings must achieve a 4-5 star standard (this varies between States). To meet BASIX requirements, your house design must receive a "PASS" under the Thermal Comfort section. A Building Thermal Performance Assessment conducted by an ABSA Assessor can be used to show compliance with these requirements.
Q: What is Thermal Performance Assessment?
A: A Thermal Performance Assessment (also commonly known as a House Energy Rating, or a NatHERS/BERS/FirstRate Rating) is an assessment of how comfortable the temperature in your house will be throughout the year.
It primarily assesses the thermal performance of the building envelope elements (walls, floors, roof, windows, insulation) to determine the home’s ability to remain comfortable with as little artificial heating or cooling as possible.
All states in Australia require new houses to meet minimum thermal performance standards. Some states have requirements for existing home owners to declare the home’s thermal performance at point of sale.
A Thermal Performance Assessment conducted by an ABSA Assessor can be used to show compliance with:
- the Building Code of Australia (Verification method), and
- the BASIX Thermal Comfort (Simulation method), and
- Mandatory Disclosure at point of sale (ACT only).
Q: How is a Thermal Performance Assessment done?
A: ABSA Assessors conduct Thermal Performance Assessments by inputting your house design into an approved computer software package. The rating is based on building fabric components (e.g. walls, floors, roof, windows, insulation), climatic data (from weather data files), and occupancy settings.
ABSA Accreditation is the only nationally recognised standard for Assessor training and Quality Assurance which meets the requirements of the Building Code of Australia and the NSW Building Sustainability Index (BASIX). In some states it is mandatory to use an Accredited Assessor to carry out Building Thermal Performance Assessments.
Your ABSA Assessor will provide you with a stamped ABSA Certificate (which is required by Councils to be lodged with your Development or Building Application) and will stamp your plans accordingly. In the event that your design does not meet the required minimum standard, your Assessor may suggest some alternatives to improve the performance of your house design.
The approved software used to generate a rating varies by state – the main tools used in Australia are NatHERS, BERS and FirstRate and are validated using a national standard. The simulation engine upon which all tools are based was developed by the CSIRO in consultation with state and federal governments.
Q: How can I find an Accredited Assessor to carry out a Thermal Performance Assessment?
A: A full list of Accredited Assessors is available on the Find an Assessor page of this website. You can search for an Assessor by region, Assessor name or Assessor number. Only Accredited Assessors are listed on our website.
When engaging an Assessor, make sure that:
1. They are an ABSA Accredited Assessor. Some states stipulate that only Accredited Assessors can conduct Thermal Performance Assessments. ABSA Accreditation also ensures that your Assessor meets requirements for quality assurance and continuing professional development.
If you are in any doubt and would like to check the validity of an Assessor’s Accreditation, ask the Assessor for their ABSA Accreditation number. You can type this into our Find an Assessor page and make sure they are currently listed.
You can also check the validity of your completed ABSA Certificate on the Check an Assessment page of this website.
2. They have adequate and current Professional Indemnity Insurance. It is an ABSA requirement that all Assessors must carry adequate insurance for their role as an ABSA Accredited Assessor. This provides security for you in the unlikely event of significant Assessor professional malpractice.
Q: How much does a Thermal Performance Assessment Cost?
A: Assessors set their own fee calculations based on their probable costs, perceived value and other pertinent financial aspects. ABSA recommends that you obtain quotes from several Assessors, as you would for any other similar service.
ABSA cannot set or recommend a fee structure for the tasks performed by Accredited Assessors. It is a breach of the Trade Practices Act 1974 to set such a structure and is defined as a 'restrictive trade practice' under that Act.
Q: I am completing a BASIX Certificate in NSW. Where can I get some assistance?
A: In NSW there is currently no Accreditation Scheme for BASIX Assessors. ABSA does however have Accredited Thermal Performance Assessors who also have experience in the required aspects of sustainable buildings. A list of individuals that provide a "BASIX Assistance" service can be found on the Find an Assessor page of this website.
Q: How do I become an Accredited Thermal Performance Assessor?
A: Please consult the Become an Assessor page of this website.