Home design standards based on outdated climate data will drive up household energy bills and put lives at risk, according to a study released by the Western Sydney Regional Organisation of Councils (WSROC).

The study, titled Future Proofing Residential Development in Western Sydney, modelled how homes built to today’s standards will perform in 2030 and 2050 as well as during heatwave conditions.

WSROC President,  Clr Barry Calvert, said: “The homes we build today will be in place for decades to come. We must ensure we are setting Western Sydney up for success.

“Unfortunately, this report shows new homes are not performing in today’s climate, let alone in 2030 or 2050, due to outdated standards in the National Construction Code (NCC) and NSW BASIX legislation.

“A key problem is the climate files used to estimate the heating and cooling a home needs to meet NCC and BASIX thermal comfort standards are decades out of date.

“Today, we are assessing new homes against a pre-1980s climate^[1], which is simply laughable. From October 2023, the climate files used for housing assessment will be updated to a pre-2010 climate^[2], however this ‘update’ is still far cooler than we experience today or can expect in future,” said Clr Calvert.

“By testing the limits of our current standards, the report found homes designed for 2050 are not allowed to be built today – even though that 2050 house would use significantly less energy for cooling in 2020.

“In essence, we are not allowed to design homes that are future-ready, that can keep people safe, reduce energy bills, and support NSW’s Net Zero targets,” said Clr Calvert.

“The second problem with the current standards is that we assess the performance of homes with the air-conditioner on.

The homes we modelled in our study became unsafe when the air-conditioning was turned off to simulate a heatwave-induced blackout or where air-conditioning is unaffordable.

“Assuming people can afford to use air-conditioning is not only a major equity issue, it puts unnecessary pressure on our power grid, leaving the city vulnerable to energy failure. This needs to change,” said Clr Calvert.

“It may not be widely known, but heatwaves kill more Australians than bushfires, floods and storms combined.

“Western Sydney has already experienced 50°C temperatures. These temperatures are not compatible with human life, and their frequency is expected to increase in future – leaving more than two million residents at-risk,” said Clr Calvert.

“We must be prepared to help people – particularly those at risk – endure these types of conditions.

“WSROC wants to see minimum thermal safety standards for Australian homes, because homes should, first and foremost be designed to keep people safe,” he said.

“Thermal safety means that homes can maintain survivable temperatures without power. This is not only important for low-income communities. Most air-conditioning units and solar panels reach operational thresholds at 45 and 50 degrees respectively. We shouldn’t be relying solely on energy-based technologies to protect us from disaster.

“The time to act is now. Western Sydney will see most of Greater Sydney’s new homes over the next five years. If we don’t get this right, the costs of future adaptation and emergency response will be enormous,” he said.

Future Proofing Residential Development In Western Sydney report is available for download from the WSROC website here. 

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^[1] Average climate data from years 1967 – 2004.

^[2] Average climate data from years 1990 – 2015.

Further information

The Future Proofing Residential Development in Western Sydney project works towards delivery of the Turn Down the Heat Strategy and Action Plan (2018). Recommendations for heat-resilient building design will inform future work to improve land use controls and design retrofit programs. The Turn Down the Heat Strategy was developed by 55 organisations across greater Sydney to create cooler, more resilient communities. This project builds on the Future Proofing Residential Development to Climate Change (2021) study by Randwick, Woollahra and Waverley councils.

Thermal performance:

Thermal performance is the amount of heating or cooling that is required to make a home a safe, comfortable space to live in. In BASIX, the most commonly used measure of thermal performance is the Nationwide House Energy Rating Scheme (NatHERS).

NatHERS uses a star-rating measure from zero to 10 to guide home designers and builders to meet the National Construction Code energy efficiency requirements. In the NCC 2022, the minimum thermal performance requirement has increased to NatHERS 7 stars.