What is BASIX?

BASIX stands for building sustainability index. It is a mandatory regulation for design and construction of residential developments in NSW since 2004. BASIX is one of the most robust and effective planning regulatory frameworks in Australia to combat the effects of climate change and environmental pollution. It is a necessary document to apply for development or a residential building anywhere in NSW. A BASIX certificate must be obtained by assessing the building design specifications and performance of its various elements and systems in the BASIX assessment online tool. The BASIX certificate will then need to be submitted to the council and the certifying authority during various applications phases from Development Application all the way to the Occupation Certificate application.

BASIX is a proven scheme to reduce the environmental impact of residential buildings in NSW and it has won several awards over the years. It was introduced from July 2004 by the Department of Planning of the NSW Government. The underlying regulations under the BASIX are Environmental Planning and Assessment Regulation 2000 (known as the EP&A Regulation) and State Environmental Planning Policy 2004 (Building Sustainability Index: BASIX), known as the BASIX SEPP.

There has been several updates and upgrades since the BASIX scheme has begun and it has won several industry and government awards .

BASIX sets certain performance targets for thermal comfort performance of a residential building as well as its energy and water efficiency. The thermal comfort targets are either satisfied by completion of a NatHERS thermal comfort computer modelling for each dwelling in the proposed development or, in the case of a single dwelling, using a deemed to satisfy solution corresponding with the deemed to satisfy requirements of the National Construction Code / Building Code of Australia Volume 2 which is called a DIY method. BASIX targets are based on the average performance benchmarks of the state of NSW. A BASIX assessment is completed using the online assessment tool which challenges the building performances in energy and water efficiency areas against these benchmarks.

What is a BASIX certificate?

A BASIX certificate is a document generated by the BASIX online tool which demonstrates the list of provisions and requirements of a residential development to comply with the regulations. For any type of new residential development or an alteration and addition to an existing dwelling over $50,000 in cost, you need to submit a valid certificate with your development application. The requirements of the certificate are mandatory and must be fully complied with during the construction of the project.

To get a BASIX certificate, sometimes called a BASIX assessor certificate, relevant information and performance specifications of various building elements and systems should be entered into the online assessment tool. This information is then used to calculate the performance of the development in comparison with the average performance of dwellings in that specific climate zone. There is more specific information below with respect to different types of dwellings and development sizes.

When the building successfully meets the required BASIX certificate compliance in the areas of energy efficiency, water efficiency and occupant thermal comfort performances, a certificate can be created and printed from the online tool. This certificate lists the specific requirements and details of that project as well as generic help notes to simplify the interpretation of these provisions during the construction and application time. This information must be reflected on the development plans for preparation of a development application or a complying development application.

Frequently Asked Questions about BASIX

After the construction of a residential project is finished and prior to issue of an occupation certificate for the project, BASIX certificate compliance must be endorsed and certified by the principal certifying authority of the project. This is done by completing a checklist which is only accessible by the PCAs from a particular section of the government website. If you have any questions regarding certificates, make sure to get in contact with our Consultants.

BASIX Single Dwelling

According to the BASIX Certificate definition of a single dwelling development, a single dwelling is an individual dwelling house which is being built on a separate land lot. It can be a separate house or an attached one of the two houses in a semi detached or attached building types. The BASIX assessment tool for a single dwelling is different in relation to the type of selectable options and inclusions compared to multi-dwellings, alterations and additions and multi-unit developments and it has no mention of common areas and their specific requirements. For the thermal comfort section compliance of the BASIX provisions, a DIY method is available in addition to the NatHERS thermal modelling option which aims to resemble the deemed to satisfy requirements of energy efficiency provisions of volume two of the National Construction Code/ Building Code of Australia. RAPID method has been removed by the NSW Department of Planning for single dwelling BASIX assessments as of 1st of July 2017. Make sure to check out our News page regarding all the updates in relation to this area.

BASIX Multi-Units

BASIX for multi-unit developments (residential flat buildings) or multi-dwelling developments (townhouses) is more complex and sophisticated compared to the single dwelling assessment option of the online tool. For multi-units we need to elaborate on the areas and types of common area spaces and nominate the energy and water efficiency provisions in those areas. These requirements will be considered in the overall energy and water score of the proposed development as well as provisions for the residential units. BASIX for mixed use developments also recognises the areas of non-residential spaces and the way they are being serviced by the building services and systems. The multi-unit assessment tool only recognises the simulation method with NatHERS to comply with thermal comfort requirements.

BASIX Alterations and Additions

The BASIX alterations and additions assessment tool is different in many areas from the single dwelling and multi-unit tools. Only a certain extent of renovation work is required to comply with the BASIX requirements for alterations and additions. If the total cost of renovation is over $50,000 and/or a swimming pool or spa is proposed with the total volume over 40 cubic meters, then the proposed development must comply with the provisions of the alterations and additions tool and demonstrate BASIX certificate compliance for the proposed renovation work.

BASIX Certificates Services Sydney NSW

At Eco Certificates we have extensive experience for developments that require BASIX certificates in Sydney and surrounding areas. Sydney’s sustainability requirements are basically high considering the fact that Sydney has the mildest climate in Australia and at the same time, due to the sheer amount of population and activity in this city, the possibilities for saving energy and water are substantial. If you are new to BASIX and would like to learn more about it, you can visit our BASIX FAQs page.

BASIX Certificates Cost


At Eco Certificates we have extensive experience for developments that require BASIX certificates in Sydney and surrounding areas. Sydney’s sustainability requirements are basically high considering the fact that Sydney has the mildest climate in Australia and at the same time, due to the sheer amount of population and activity in this city, the possibilities for saving energy and water are substantial. If you are new to BASIX and would like to learn more about it, you can visit our BASIX FAQs page or check out this well written short PDF with all the important facts for BASIX.

BASIX Certificate Commitments are Mandatory

A poorly prepared certificate can incur heavy expenses during the construction phase with little or no added benefits.
Use our professional services to get the best possible BASIX solution for your development.

BASIX Consultants at Eco Certificates

Our BASIX consultants are amongst the most experienced in the industry. Since our establishment in 2009, we have been a focused consultancy firm in various areas of building energy modelling and sustainability. BASIX has been a focal and main part of our services since the beginning and our consultants have been engaged in every imaginable scenario and project type. Assessment of a residential project for compliance with BASIX can become tricky and complicated quickly if the building is not performing well in one or more of the thresholds. There are many interconnected and related areas of the algorithm which need to be considered while performing an assessment and an experienced BASIX Consultant can introduce a noticeable difference in the final outcome of the project and its development cost.

To stay on top of our game and preserve our name as the most reliable consultants in front of our clients we take ongoing research and training very seriously. This is particularly true in cases of major updates and regulation introduction by the government. A consultant must be ready for any of updates to be implemented in the online assessment tool before they are enforced by the government. We also train our consultants in general areas of building systems, passive design principles, building materials and emerging technologies.

What is a BASIX Report?

A BASIX report is a not a BASIX certificate and cannot be used for a development application submission with the council. It shows all the information which would result from the assessment of a residential development using the online tool and it is identical to the final certificate. A report is a very useful document to review and fine tune the requirements of the project prior to payment for the actual certificate and submitting it to the council. We always issue a draft report when our NatHERS thermal modelling and assessment is completed to our clients so they can review and confirm all the commitments and requirements of the project on that BASIX report prior to finalising and issuing the certificate.

How much does a BASIX Certificate cost?

There are two components in a BASIX certificate cost. The first are the fees which are charged by the government entities. The NSW Department of Planning, which is the governing body of the BASIX scheme, charge for each certificate that is created by the online assessment tool based on the nature of the development and the number of dwellings. For more details, please visit our BASIX Certificate Cost page. The cost is also influenced by the amount of NatHERS certification fees which must be paid to release a NatHERS certificate for a project. This price is currently $30+GST per dwelling.

Our service fees are another component of the cost. We always aim to be as competitive as possible and offer the lowest cost for the BASIX certification service we provide. Our focus on price is based on offering the maximum amount of value to our customers in relation to costs, project turnaround time, expedited updates, and availability to respond to any nature of client enquiry and request.

What is a BASIX Assessment?

To complete a BASIX assessment the most important step is to classify the type of development as there are different online assessment tools for different types of residential buildings. The BASIX assessment process is studying the building specifications and design plans and introduction of the required information to the online assessment tool. Based on the project type, we may be required to enter the heating and cooling loads of each dwelling in the proposed development in the thermal comfort component of the online assessment tool. The information which are applicable to any type of development is:

• development details
• energy and water efficiency performance of systems installations of each dwelling
• thermal performance properties of each dwelling
• common area specifications and energy and water provisions
• renewable energy and recycled water considerations in the project

The BASIX assessor who prepares the project for compliance could be a member of HERA or DMN and be a NatHERS accredited assessor. A HERS BASIX Certificate is identical to one which is created by a DMN assessor as both organisations are equally validated by the NSW Department of Planning. Well recognised and accredited BASIX assessors who are also accredited under the NatHERS regulations can perform the thermal modelling for compliance with the thermal comfort section of the assessment tool.