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The Building Sustainability Index (BASIX) aims to deliver equitable, effective water and

greenhouse gas reductions across the state. BASIX is one of the strongest sustainable

planning measures to be undertaken in Australia.

As of June 2015 BASIX has issued a new specification which all drawings must adhere to for the purposes of a NatHERS Thermal Comfort Simulation Assessment. Please be advised the AENEC is fully compliant with the latest version of AccuRate Sustainability.


An integrated part of the planning system, BASIX is implemented under the Environmental Planning and Assessment Act. BASIX applies to all residential dwelling types and is part of the development application process in NSW.


BASIX is assessed online using the BASIX assessment tool. The tool checks elements of a proposed design against sustainability targets.


BASIX reduces water and energy consumption in homes across NSW. These environmental outcomes also provide a long term financial saving for the homeowner – and a valuable contribution to the sustainable future of our communities.


That is why you need to use our professional service. As we do BASIX assessments, BASIX certificates day in and day out, we have all the required experience and we will ensure that you will not be out of pocket with unnecessary provisions and technical solutions.

BASIX New Targets

The new BASIX targets mainly affect the thermal comfort section as BASIX heating and cooling loads parameters have been altered significantly.


What does this mean for the new developments?

  • Basically, the building must be able to perform better both in summer and winter in order to meet minimum requirements

  • Window areas may need to be reduced in comparison the old standards

  • Window specifications may need to be increased and sometimes significantly to meet new standards

  • Higher levels of insulation may need to be added

  • Higher thermal mass can be considered

  • Higher build costs all up

  • Better homes to live in

  • Much lower running cost of the buildings

  • More environmentally friendly buildings

What is currently a hindrance, and what we as assessors have asked the regulators, is to allow us to model ceiling fans as they play a very important role in keeping the dwelling cool in summer. They also allow for lower window specifications overall, hence keeping costs to lower levels, however in NSW, currently we do not have this option available to us.

If you are about to start designing your new project, look for;

  • Orientation and sun exposure are two very important factors, so where possible use them ti benefit your outcomes

  • Build as close to the square shape as possible. Long and narrow buildings tend to suffer either in summer or winter and in some cases throughout the year

  • Limit as much as possible glazing areas

  • Utilize openable windows rather than fixed where possible

  • Keep an open mind for color tone scheme as they play an important role too


We hope that this short article has been useful and if you like to find out more, you can contact us as or look at the quick cost guide page.

BASIX - New Homes & Apartment Buildings - NSW

All new houses and apartment buildings are required to have a BASIX certificate completed as part of development applications. The BASIX tool has three segments:

  • Water Efficiency

  • Thermal Comfort

  • Energy Efficiency


Nominally a reduction of water consumption by a minimum of 40% compared to a standard house (house without any water saving measures) for new houses/townhouses and by 30% compared to a standard apartment for apartments. The water usage reduction for

apartments, sometimes is also at 40% depending on suburb, size of development, etc. 


Water efficiency is primarily achieved via the use of rated water appliances (shower heads, taps, cisterns), the utilization of rainwater tanks for garden watering usage and sometimes for laundry,

and toilets as well as pools whenever applicable.


NatHERS is a national scheme although not compulsory to all states, however is compulsory in NSW. It is a scheme where dwellings are rated according to their thermal performance for summer and winter. That is achieved via the simulation of the proposed

dwelling by specialty software packages such as Firstrate and HERO. The way this is done is the whole geometry of the subject building, including neighboring buildings for shading, location, orientation and building constructions are inputted. All of the above are calculated thus predicting cooling and heating loads. BASIX has benchmarks for these loads mainly dependent on location and building type, however other secondary parameters are taken into consideration.

Once the software produces the predicted loads, they then are compared to BASIX benchmarks. If loads are higher than allowed, mainly construction specifications (walls types, insulation levels, window types, colours etc) are altered / optimized in order to make the dwelling comply.

Single dwellings can also be assessed via the use of the simple method, a method that can be assessed by anyone however be careful on the commitments as they will be checked by the certifier and non-compliance, will need to be addressed.


Similarly to the water efficiency section, electric appliances such as water heaters, a/c, lights, and other, sometimes including solar photo-voltaic systems are specified in order to achieve 30% - 40% energy usage reduction compared to a standard dwelling. Thermal comfort section can affect the energy efficiency performance as a well, since a well performing dwelling requires little on no a/c usage, thus contributing positively to this section.​

All of the above is combined in one document, the so called BASIX certificate and is used as a specification sheet for architects and builders for the building phase and as a checklist for building certifiers at the completion stage of the project in order for the Occupation Certificate to be issued.​

All information outlined in the BASIX certificate and in the HSTAR universal certificate (thermal comfort section) must be reflected 100% in the building.

In other states, BASIX is not applicable and reference solely to the BCA is taken into account, however for thermal the comfort, NatHERS is the only scheme available


To address the thermal comfort section of BASIX, AENEC provide their clients a thermal simulation by using the latest software packages and is able to provide you with complete and accurate design advice.


AENEC also specializes in multi-unit BASIX certifications for apartment buildings and having assessed many multi-unit projects we have an extensive knowledge of the process.


For our multi-unit fee schedule, please contact us.

BASIX Legislation

Planning in NSW is largely governed by the following two pieces of legislation:

  • Environmental Planning and Assessment Act 1979 (or “the EP&A Act”), and the

  • Environmental Planning and Assessment Regulation 2000 (or “the EP&A Regulation”).


While the Act and the Regulation provide the overarching structure for planning in NSW, there are a number of other statutory documents that support that structure.


The two most commonly used are State Environmental Planning Policies (SEPPs) and Local Environmental Plans (LEPs).​

  • State Environmental Planning Policies (SEPPs).

There are approximately 66 State policies and that outline the NSW Government’s approach to dealing with planning issues specific to the State and people of NSW. State policies are made by the Governor on the recommendations of the Minister for Planning and updated as required.​

  • Local Environmental Plans (LEPs).

Each local government area has a LEP to guide development and protect natural resources such as waterways and heritage within local government areas. LEPs are prepared by councils, in consultation with their community and approved by the Minister for Planning (or their delegate).


Although the rules and guidelines for land use within council areas are dictated to some degree by State Environmental Planning Policies, councils can administer more specific rules about land use through their Local Environmental Plans, and can provide additional guidance in their development control plans (DCPs).

For More Information Click HERE

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