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BASIX for Alterations, Additions and Swimming Pools

Alterations and additions

BASIX Alterations and Additions is a NSW Government initiative that will require household renovations to include cost-effective and practical measures to reduce greenhouse gas emissions and potable water consumption, and improve thermal comfort. BASIX Alterations and Additions has become mandatory across NSW on 1 October 2006. 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.

Alterations and additions-Simulation method

Modelling process

The modelling process for alterations and additions is much more involved than for a new dwelling. You will need to run three separate simulations:

  • 1. Existing: model the existing dwelling, and document all assumptions about the thermal performance of the existing building fabric.
  • 2. Reference: model the entire existing dwelling and the alterations and additions, with all new work complying with the relevant BASIX Construction and Glazing commitments. You must not change the assumed performance of the existing building fabric.
  • 3. Proposed: model the entire existing dwelling and the alterations and additions, but with the actual proposed performance for the new building elements. Only change the performance of the parts of the existing building fabric where new work is being done such as installing additional insulation or replacing a window.

Basix-Swimming pools

  • If you are building a new dwelling and including a swimming pool of any size it will need to comply with BASIX.
  • If you are lodging plans for your pool as an alteration and addition you will need to comply with BASIX only if the volume of the pool is more than 40,000 litres.
  • The BASIX requirements relating to the installation of a pool will depend on pool size, heating type and the water target zone.