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Housing - Increases to BASIX


Increase to BASIX Standards

Information about the increases to BASIX standards that took effect on 1 October 2023.

Increases to the existing BASIX standards came into effect on 1 October 2023. The increases include higher thermal performance standards and higher energy standards. There is also a new requirement to calculate and record embodied emissions of building materials.

The standards have increased for all new residential buildings across NSW except homes in climate zones 9, 10 and 11 (in north-eastern NSW) and apartment buildings up to 5 storeys.

The new standards will result in:

  • cheaper energy bills. You’ll use less electricity so your bills will be cheaper – you could be saving as much as $980 a year on energy bills.
  • more comfortable homes. Your home will be naturally cooler in summer, warmer in winter, which means you won’t be turning the heater or air conditioner on as often.
  • fewer carbon emissions. This contributes towards our goal of net zero homes by 2050.

BASIX has stopped 12.3 million tonnes of greenhouse gas from going into our air since 2004. Our updated standards will save another 150,000 tonnes of greenhouse gases a year. This is equal to running 31 wind turbines, enough electricity to power 27,000 homes each year, or planting around half a million trees. 

The higher standards were introduced via the State Environmental Planning Policy (Sustainable Buildings) 2022. The increases also align with NSW and national policies to achieve zero emission homes, such as the Net Zero Plan Stage 1 and the national Trajectory for Low Energy Buildings.

In June 2023 we hosted a webinar on how to meet the higher BASIX standards. Our panel of building industry experts shared their experience on designing homes to meet the higher standards and help you build more sustainable homes.

We also have examples of how you can meet the higher standards for different home orientations and different climate zones.

Additional transition period for signed building contracts

Homebuyers who signed a building contract for a new house or duplex before 1 October 2023 can apply to use the current BASIX standards in the BASIX tool. Eligible applicants can generate a BASIX certificate that meets the current standards up until 30 June 2024. However, we are working on an amendment to the Sustainable Buildings SEPP to extend this transitional period by a further 3 months to end on 30 September 2024. Applicants must submit the BASIX certificate with their development application or complying development certificate before it expires. BASIX certificates are valid for 3 months. The concession does not apply to apartments.

Find out more about how the BASIX standards apply and the limited transitional arrangements in place.

Higher thermal performance standards

BASIX thermal performance standards are designed to limit the amount of heating needed in winter and cooling needed in summer. These limits are known as heating and cooling caps. 

The standards use the Nationwide House Energy Rating Scheme (NatHERS) to estimate heating and cooling loads. NatHERS is based on past meteorological records and covers weather data up to 2015. The total heating and cooling needed for one home can be compared to another using NatHERS.

The new thermal performance standards increased from a range between 5.5 and 6 star NatHERS on average to 7 stars, to align with the National Construction Code (NCC) 2022.

Changes to thermal performance standards (table)

Building type Current standards Higher standards
Detached or attached houses
  • Heating and cooling caps to deliver average 5.5-6 NatHERS star outcomes
  • 7 NatHERS stars
  • Revised heating and cooling caps
  • Heating and cooling caps to deliver average 5.5-6 NatHERS star outcomes
  • Maximum heating and cooling caps for individual apartments


Across the building:

  • Average 7 NatHERS stars across the building
  • Average heating and cooling caps

Individual apartments:

  • Minimum 6 NatHERS stars
  • Maximum heating and cooling caps

Changes to the DIY method that affect the use of dark roofs

To align with the deemed-to-satisfy elemental provisions of the NCC 2022, we are making changes to the DIY method that affect the use of dark roofs. This means that for developments in coastal areas north of Wollongong (including Greater Sydney) and inland areas west of the Great Dividing Range, dark roofs (i.e. with a solar absorptance greater than 0.7) cannot be selected with the DIY method. Dark roofs can be selected in other locations in NSW. 

For the alternative thermal performance pathways of the Simulation method or the Passive House standard, dark roofs are still an option that can be modelled.

However, where it is allowable to select dark roofs, increases to other design specifications will usually be required to meet the BASIX standards.  


Higher energy standards

BASIX energy standards are expressed as a percentage reduction in carbon emissions from the pre-BASIX benchmark of 3,292 kg CO2-e/(person/year). The BASIX energy standards depend on the climate zones defined by NatHERS. 

Two factors contribute to the higher BASIX standards: an increase in stringency (energy performance) and the reduced greenhouse gas emissions of grid electricity.

The new energy efficiency performance requirements for the NCC are quantified in terms of energy value or net cost to society. The increase to BASIX energy standards align with the provisions of the NCC 2022. The higher standards continue to vary by home type and climate zone. The BASIX energy standards continue to be measured using carbon emissions.  

Changes to the energy standards for detached houses and high-rise apartment buildings  

Building type  Current energy standards  Higher energy standards 
Detached houses  Standards do not vary with floor area  Standards will vary with total floor area. This is to account for energy consumption and the number of people that live at a property. For example, A small house with a floor area of 100m2 will have different standards to a large house with floor area of 250m2. 
High-rise apartment buildings   The same standards apply to apartment buildings 6 storeys and higher. 

Two separate standards for high rise apartment buildings:  

  1. 6 – 20 storeys 
  2. 21 storeys and higher  

This will account for the energy consumption of shared services specified in high-rise buildings.  

Other changes to the BASIX energy section  

In response to feedback from stakeholders, we are introducing the following changes to the BASIX calculations:  

  • Incorporating the NatHERS whole-of-home calculation to align with the national requirements in the NCC, including how the number of occupants is estimated 
  • Assuming installation of energy efficient lighting (such as LEDs) in houses and apartments  
  • Updating the default efficiency settings of household appliances like fridges and dishwashers 
  • Removing star rating selections of fridges and washing machines* in apartments to: 
    • ensure building designers are focused on improving building façade and fixed energy systems to satisfy BASIX energy standards.  
    • reduce waste if occupants move into new apartments with their own fridge and washing machine.  

There are also some changes specific to apartment buildings: 

  • Lift inputs and calculations will be revised to include lift banks and express zones. Tempered air supply will be an option for ventilating lift lobbies and corridors. This is in addition to the current supply, exhaust and air conditioning options.  
  • Calculations to estimate energy consumption from central heat pump hot water systems with gas boosters will be revised to improve consistency with other options. 

*Users can continue to select star ratings of dishwashers and clothes dryers, as occupants often rely on these appliances to be installed in a new unit.  

Updating greenhouse gas emissions factor of grid electricity  

The greenhouse gas emissions factor is the volume of emissions (expressed as kilograms of carbon dioxide equivalent (kg CO2-e)) generated and transmitted from each unit of grid electricity to households. BASIX currently uses an emissions factor of 1.062 kg CO2-e for each kilowatt-hour (kWh) of electricity.  

The NSW electricity grid has become greener as we produce more electricity from renewable energy sources. We have recognised this in the higher energy standards by updating the greenhouse emissions factor of grid electricity.   

This graph shows that the emissions factor from grid electricity in NSW will be reduced significantly in the next two to three decades.  

A 10-year average from 2022 to 2031 (or 0.67 kg CO2-e/kWh) will be adopted for calculating BASIX energy scores from 2022.

New materials index

The new BASIX materials index calculates and reports on the embodied emissions of a home. The tool does this by estimating the volume of different materials used in construction and applying the emissions factors for the materials.

The emissions factors represent embodied emissions from the production of each building material. Default factors for embodied emissions of materials are based on the EPiC database. Although the initial materials index does not account for the full lifecycle impact of building materials, we will consider other factors such as durability and transport of building materials in future revisions.

The embodied emissions calculations have been tested by many BASIX users, including builders adopting the higher standards ahead of 1 October 2023. This experience revealed a complex relationship between the thermal performance standard and embodied emissions. As a result, there is currently no limit on embodied emissions of building materials. We will consider setting a limit (or standard) in the future.

We have prepared a help note about the new materials index, which will be available to download until more detailed help notes are embedded into the enhanced BASIX tool.

New materials index help note

We have also developed a calculator to help you determine the areas of walls and glazing to enter into the materials index.

Walls and glazing calculator

Increase to BASIX Standards exhibition

Increase to BASIX standards (as exhibited)

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Last updated: 17/04/2024