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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 component of the design and development or a residential building 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 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 department of planning of the NSW Government. The underlying regulation under the BASIX are Environmental Planning and Assessment Regulation 2000 (known as the EP&A Regulation) and State Environmental Planning Policy (Building Sustainability Index: BASIX) 2004 (known as the BASIX SEPP).

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 of it are either satisfied by completion of a NatHERS thermal comfort computer modeling for each dwelling in the proposed development or, in case of a single dwelling, using a deemed to satisfy solution corresponding with the deemed to satisfy requirements of the 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. BASIX assessment is completed using online assessment tool which challenges the building performances in energy and water efficiency areas against these benchmarks.


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, boarding houses under 300 square meters and an alteration and addition to an existing dwelling over $50,000 in cost, you need to submit a valid certificate with your application.

To get a certificate, sometimes called BASIX assessor certificate, relevant information and performance specifications of various building elements and systems should be entered into the online assessment tool. This information are then used to calculate the performance of the development in comparison with the average performance of dwellings (there is more information below about different sorts of dwellings) in that particular climate zone.

 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.

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.

All your questions regarding BASIX answered here!

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. BASIX assessment tool for a single dwelling is different in type of selectable options and inclusions compared to multi dwellings and multi unit development and have no mention of common areas and their requirements. For the thermal comfort section compliance to the BASIX provisions, a DIY method is available in addition to the NatHERS thermal modeling option which roughly tries to resemble the deemed to satisfy requirements of energy efficiency provisions of volume two of the 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 this field.

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 type 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 units 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 need to 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 certificates in Sydney and surrounding areas. Sydney Certificate requirements are basically high considering the fact that Sydney has the mildest climate in Australia and at the same time, due to 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 about it quickly, you can either visit our BASIX FAQs page or just check out this well written short PDF with all the important facts for BASIX.

BASIX Certificate Commitments are Mandatory

A poorly prepared certificate can incure 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 2008 when we started we’ve been a focused consultancy firm in various areas of building energy modeling 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 needs 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 it’s development cost.

To stay on top of our game and preserve our name as the most reliable consultants in front of our clients we do 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 the changes coming to the online assessment tool way 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 actually 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 modeling 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 is a BASIX Certificate Cost

There are two components in a BASIX certificate cost. The first are the fees which are being charged by the government entities. Firstly, the NSW department of planning which is the governing body of the BASIX scheme started to charge for each certificate which is being created by the online assessment tool based on the nature of the development and the number of dwellings. For more details please visit this page of our website. The cost is also influenced by the amount of NatHERS certification fees which must be paid to release a NatHERS certificate for a project. At this point in time, this price is $20+GST per dwelling.

Our service fees is another component of a the cost. While we’ve always tried to be as competitive as possible and offer the lowest cost for the BASIX certification service we provide, we’ve not always been able to be the absolute cheapest. Our focus on price is based on offering the maXimum amount of value to our customers when it comes to costs, project turn around 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 because 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 online assessment tool. Depending on the project type, we may require to enter the heating and cooling loads of each dwelling in the proposed development in the thermal comfort of 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 ABSA or BDAV and be a NatHERS accredited assessor. An ABSA BASIX certificate is identical to one which is being created by a BDAV assessor as both organisations are equally recognised by the NSW department of planning to recognise and accredit BASIX assessors who are also accredited under the NatHERS regulations to perform the thermal modeling for compliance with the thermal comfort section of the assessment tool.

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