Brisbane Tops National Rankings for Cost-Effective Home Energy Upgrades

An undated supplied photo of Zoe Cheihk's massive Brisbane property, Rivergum Retreat, released Aug. 14, 2006. AAP Image/Jason Adcock

A report revealed that Brisbane is the most affordable major Australian city for upgrading new homes to achieve a seven-star energy efficiency rating, with an average cost of just $2,972 (US$2,050). This figure is significantly lower than the national average of $4,311.

In comparison, new homeowners in Western Sydney spend an average of $4,105 to reach seven-star compliance, while those in Perth spend $4,262, and homeowners in Melbourne face an average cost of $5,905.

Graham Energy, a sustainable building consultancy, compiled the report titled 7.0 Star Cost Upgrade Analysis.

The 2022 National Construction Code (NCC) mandates that all newly constructed houses and apartments in Australia achieve a minimum energy efficiency rating of seven stars under the Nationwide House Energy Rating Scheme (NatHERS).

A higher score means the home spends less energy when heating and cooling to maintain a comfortable temperature.

When these new standards were adopted in August 2022, Building Ministers said that they would enhance living conditions and reduce household energy costs.

Clinton Skeoch, Executive Director and CEO of the Australian Glass and Window Association (AGWA), said the report is the most comprehensive NatHERS modelling study ever undertaken. The costing report examines the actual 2024 costs of seven-star energy compliance.

“This report makes it clear that achieving seven-star energy compliance for new homes isn’t as costly or complicated as projected in previous public discussion, especially if you are building in Brisbane,” Skeoch said.

Window to Seven-Star Efficiency

The report’s analysis focused on the two most prevalent building types in new home estates across major Australian cities: detached three-bedroom, single-storey homes and four-bedroom, double-storey houses.

It examined a wide array of building scenarios and cost-influencing factors related to these types, considering nine different climates and 16 orientations.

Additionally, the study assessed 433 window options and evaluated window-to-floor aspect ratios ranging from 28 percent to 20 percent, with a national average of 23 percent.

Other factors included shading and overshadowing, providing a comprehensive overview of the elements impacting energy efficiency and compliance costs for new homes.

Another 2022 study by the Australian Building Codes Board (ABCB) examined the cost of achieving seven-star energy efficiency ratings in new homes across Australia.

The findings revealed that upgrades could cost between $3,000 and $6,000, depending on location, design, and materials.

Like the Graham Energy report, the ABCB study emphasised the importance of window upgrades, better insulation, and efficient heating/cooling systems to meet energy standards.

“With the right planning and advice, new homeowners can incorporate design features and material choices that make a big difference to their home’s rating outcome without breaking the bank,” Skeoch added.

According to government data, available on energyrating.gov.au, windows play a crucial role in the energy efficiency of Australian homes.

They are responsible for up to 40 percent of heat loss—which results in the surprisingly cold homes during winter—and an astonishing 87 percent of heat gain in residential buildings.

This significant impact underscores the importance of effective window design in minimising energy consumption.

In their paper “Optimal Window Designs for Australian Houses,” researchers Tom Simko and Trivess Moore revealed that windows account for 1.5 percent of Australia’s total energy consumption.