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Basix page

Dwelling types

Alterations and additions

This tool allows registered users to generate BASIX certificates

This tool allows registered users to generate BASIX certificates for the following purposes:

  • to alter, enlarge or extend an existing BASIX-affected building
  • for a swimming pool or spa, or combination of swimming pools and spas, that serve only one dwelling.

The tool can also be used to generate a BASIX certificate for a secondary dwelling where that dwelling is created by converting existing habitable space within the primary dwelling. View more information on using BASIX for secondary dwellings and granny flats.

BASIX applies to all alterations and additions in NSW that are valued at $50 000 and over and/or involve the installation of a pool and/or spa with a total volume greater than 40,000 litres.

The BASIX assessment tool has a section specifically designed for alterations and additions to existing homes. This section differs slightly from the single dwelling and multi-dwelling sections of the tool in that there are no set reductions for energy or water.

Instead the tool aims to reduce potential water consumption and emissions by encouraging efficiency improvements. The alterations and additions section of the BASIX assessment tool:

  • Reduces the energy required to heat and cool homes through improved glazing, insulation, building design and construction materials
  • Requires at least 40% of new or altered light fixtures to be fitted with high efficiency globes
  • Promotes the installation of solar, gas, heat pump or wood systems instead of high emission electric hot water systems
  • Requires all new taps, toilets and showerheads have a minimum efficiency rating of 3 WELS stars
  • Reduces pool and spa emissions by phasing out high emission electric heating systems
  • Reduces water consumption in pools and spas by encouraging rainwater tanks and covers to reduce evaporation

If the alterations and additions are valued at $50 000 and over and are not for use as a dwelling (or capable of being used as a dwelling), you need to check with your local council if BASIX applies.