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Basix - Building Sustainability index

Basix Certificate

BASIX or Building Sustainability Index is a scheme introduced by the government of New South Wales, Australia to regulate the energy efficiency of new buildings and buildings which is to be renovated. New Building Introduced by the NSW Government, BASIX, the Building Sustainability Index, ensures homes are designed to use less potable water and be responsible for fewer greenhouse gas emissions by setting energy and water reduction targets for house and units. BASIX is one of the most robust sustainable planning measures in Australia, delivering equitable and effective water and greenhouse gas reductions across NSW. Alterations and additions The Building Sustainability Index was introduced by the NSW Government on 1st July 2004.

Basix - Building Sustainability index - New dwellings

Based on the information provided about the design of the development; the BASIX Tool calculates:

  • a water score and an energy score - higher is better, and
  • for thermal comfort performance, a heating load and a cooling load - lower is better.
The water and energy scores represent the estimated water and energy consumption of the development compared to the consumption of a similar benchmark dwelling prior to the introduction of the BASIX requirements in 2004. For example, if a proposed house has a water score of 40%, it means the BASIX Tool has estimated it will use 40% less water than a similar benchmark house.

For thermal comfort performance, a high heating load indicates it will have relatively high heating costs in winter to keep the home warm. Similarly, a high cooling load indicates it will have relatively high cooling costs in summer to keep the home cool.

The BASIX requirements

The BASIX requirements consist of:

  • A water savings target, which depends on the location - it ranges between 0% and 40% - see . water target map
  • An energy savings target, which depends on the location and the type of development (different targets apply to houses, and low, medium and high rise apartments) ranges between 10% and 50% - see energy target map
  • For thermal performance, a heating cap and a cooling cap, which depend on the location and the type of development (different caps apply to houses and apartments) - see Tables A and B of the BASIX Thermal Comfort Protocol
The water and energy savings targets vary by location to ensure the BASIX requirements do not place an excessive cost burden on developments in certain regions.

Meeting the BASIX requirements

To meet the BASIX requirements, a development must have:

  • a water score that meets or exceeds the water savings target
  • an energy score that meets or exceeds the energy savings target, and
  • for thermal comfort performance, a heating load less than the heating cap, and a cooling load less than the cooling cap.

There are two options to meet BASIX compliance for thermal comfort: the Do-It-Yourself (DIY) Method and the Simulation Method. Your specific house design, including the number of windows and the size of the home, will generally determine the best method for assessment. We can assist in both forms of assessment. However, we have found that in the majority of cases, undertaking the Simulation Method generally works out to be the most cost-effective option.


BASIX DIY Method

Using the BASIX glazing calculator, the DIY Method often offers very little flexibility and typically requires the installation of improved window glazing, which can add a lot of cost.

BASIX Simulated Method

With the Simulated Method, an accredited thermal assessor uses approved software to model the house, allowing for a lot more flexibility. This method allows for the inclusion of added insulation, ventilation and shading devices, which usually removes the need for improved glazing - delivering a much more cost-effective outcome.