If you are a builder in NSW or a home owner building a home then you need to know what Basix is and how best to comply
There were a number of changes to BASIX (or the NSW Building Sustainability Index) measuring the energy and thermal comfort levels in homes, with an increase in requirements on the 1 July 2017. Now, that did not impact builders straight away as there was an allowance or transition period to any impacted by these changes. Those builders with a contract value under $1.5m got an additional 6 months to achieve compliance, but this has now also ended on the 01/01/18, so full compliance is now required since the end of Dec 2017. As a result of these changes, the NSW BASIX scheme now requires about a 6 star equivalent rating, compared to the NatHers 10 star system.
Builders are just now beginning to consider the impact of these changes and many are not ready to achieve compliance with the increased targets as they have not worked these changes into the design stage of the building process yet.
BASIX endeavours to deliver less water use and less greenhouse gas use across NSW, and the measures or requirements apply to all residential dwellings. It is generally assessed online (the DIY method) using the BASIX assessment tool and this checks specific elements of the proposed design against preset targets. The other method, the simulation method of assessment is a more detailed and specific method and will be carried out by an accredited assessor.
Looking specifically at thermal requirements, BASIX sets minimum performance levels, or ‘caps’, for the thermal performance and comfort of a dwelling. This is expressed as the annual amount of energy required to heat and cool the dwelling (MJ/m2/year). On the 01/07/17, the Planning and Environment department issued the BASIX® THERMAL COMFORT PROTOCOL paper and in this it states that “The Thermal Comfort Index of the BASIX tool assesses the heating and cooling loads placed on a new dwelling by its fabric.”
The targets that need to be achieved are expressed as a percentage saving against the preset NSW benchmark. While the benchmark is constant across NSW, the targets are varied to suit regional climates and can be amended over time. The Simulation method conducted by accredited assessors will include many variables proposed in the design, such as construction type, insulation, glazing, shading etc. Some of these occur naturally (and for free) and can contribute to a better rating such as trees and vegetation that contribute critical shading. Other factors like improved ventilation to achieve thermal comfort need to be built into the design. The home owner and the builder need to achieve a minimum BASIX rating so they need to consider the best payback options considerations such as Low-e Glass across the whole of a home or a ventilated ridge. These choices made during the design stage will impact ratings in different ways and will have a significant cost factor difference.
Investigating low cost, smart options like www.rapidridge.com.au, that provide an additional half a star (on average), can save significantly in costs when a certain rating needs to be achieved during the design stage. Compare this to the requirement of one side of the home being completed in Low-e Glass to achieve a similar rating. Same outcome perhaps but significantly different cost! A home owner and builder need to understand BASIX so they can achieve requirements in the most efficient and economical way. ‘Your money is better invested in an energy efficient building than spent on heating and cooling’ according to ‘Your Home’ and achieving an energy efficient building can be done in a number of ways.