New homes throughout Australia will need to be healthy, resilient and energy efficient to achieve certification under a Green Star rating tool set to come into action next year.

The Green Building Council of Australia has unveiled the draft of its Green Star for Homes standard, which will certify that homes which are designed and constructed to the standard are healthy, environmentally sustainable and resilient to extreme weather events and climate change.

Primarily aimed at the volume building sector, the new tool will not compete with the existing Nationwide House Energy Rating Scheme (NatHERS) or be an alternative to NatHERS.

Rather it will include a minimum NatHERS rating (see below) but will also require features in areas beyond energy efficiency along with further energy efficiency requirements.

Unlike Green Star rating tools which apply to commercial buildings, meanwhile, Green Star for Homes will not involve four, five and six-star scores.

Rather, homes will either be certified or not certified.

To achieve certification, homes will have to meet fifteen criteria under three categories:

• A health category under which homes will need to offer good light and air quality, limit moisture build-up and be constructed of materials which comply with limits regarding volatile organic compounds.
• A resilience category, under which homes will need to be well-prepared to adapt to changing climate conditions and will need to manage their own contribution to resilience by reducing their own water consumption and impact upon urban heat.
• A positive category, which requires homes to minimise energy costs and emissions through achieving minimum NatHERS ratings of seven stars (seven and a half stars in cooler climates), have double glazed windows, be airtight, be well ventilated, be fully electric, have efficient appliances, be able to generate sufficient renewable energy to be NetZero over the year and contain user guides on how to operate the home efficiently.

These categories, GBCA says, are important.

With 57 percent of Australia’s built environment emissions coming from homes (40 percent of which is used in heating/cooling – mostly heating during winter), homes make up an important part of the building sector’s carbon footprint.

With 90 percent of our time spent indoors (and two-thirds of this spent at home), meanwhile, healthy home environments are important for wellbeing.

Finally, events such as the recent bushfires highlight the need to improve resilience standards in the design and construction of new homes.

Primarily, the standard is aimed at the volume building industry and aims to influence the design of detached homes, units and townhouses (Class 1a buildings).

Targeting the standard at this sector, GBCA believes, will help to deliver change at a wide scale.

The standard allows for two types of certification.

The Green Star Designed certification allows volume home builders to achieve certification for homes which have been designed to meet the standard.

This will enable developers to market the sustainability credentials of homes which are yet to be constructed and to achieve certification for all homes which are built under standard designs.

Once homes are completed and have been demonstrated through testing to comply with the requirements of the standard, they will be able to be Green Star Certified and be marketed as having been built to the standard.

Certification may be denied for homes which are constructed on sensitive sites.

This could include, for example, areas where habitats of ecologically sensitive species have been cleared to make way for development.

Several developers have committed to piloting the new draft standards through an early access program.

These include Stockland, Mirvac, Metricon and Rawson Homes, along with Chatham Homes, Passive House, Landcom and Development Victoria.

GBCA Chief executive officer Davina Rooney said the standard will deliver health benefits to residents and will help to future-proof Australia’s residential sector.

“By significantly lifting the standard to which new homes are designed and built we can dramatically improve health and wellbeing while at the same time lowering energy bills and helping to meet our emissions reduction commitments,” Rooney said.

“Drought, bushfires and now the coronavirus pandemic have all underscored how vital it is to have more resilient housing that better protects the health of residents and the planet.”=

Rooney said the importance of housing should not be underestimated.

“With our population set to continue growing to 31 million people by 2030, we will need to build an extra 197,000 new homes every year to meet demand,” she said.

“Australians are already feeling the worsening impacts of natural disasters and paying among the world’s highest energy bills, so we must act now to ensure this pipeline of new homes is built to higher sustainability standards.”

Consultation on the draft standard will run until 30 October 2020.

The final standard and certification program are expected to be released next summer.