The BASIX basics

BASIX legislation requires all new homes to use 40% less potable water and produce 40% fewer greenhouse gases than the average home in NSW. The BASIX tool is online software that predicts how much energy and water a planned home will use. When the tool predicts that a proposed home will meet the targets for using less water and energy, it will issue a BASIX certificate.

No NSW local government area will accept a development application for a new dwelling without a BASIX certificate.

There are three main components to BASIX: water, energy and thermal comfort. The water component predicts how much water a new home will use based on information including how much landscaping is planned for the block, whether there’s a pool and how many bedrooms and bathrooms a house has. By using water efficient fixtures, new home buyers can reduce the amount of water used by showers, taps and toilets.

However, it’s virtually impossible to use 40% less potable water than the average house simply through sensitive fixture selection. Most new homes will have to reduce their use potable water use by finding an alternative water source. In 80% of BASIX compliant homes built in 2004/5, this alternative water sources was a rainwater tank that directed water collected on the roof to the garden taps, toilets and laundry.

The thermal comfort component of BASIX aims to assess how warm or cool your house will be before active heating and cooling. Factors affecting this will be what materials your new home is constructed from, how much sunlight will be able to enter and leave through glass windows and doors, and where you home is located.

Thermal comfort is actually pretty easy to pass. The real challenge is to not just pass, but excel at this component. This is because the thermal comfort score predicts your heating and cooling loads, which have a big effect on energy, the final component of BASIX.

If the thermal comfort load predicts that your house is going to be an ice box in Winter and a sauna in Summer, then BASIX presumes that you’re going to be using big, artificial energy-zapping climate control appliances basically year round. If this is the case, in order to use 40% less energy then the average NSW home, and create less greenhouse gases, you’re going to have to install the most energy efficient cooling systems possible, which also tend to be the most expensive.