The urgent need for thermal efficiency

Improving the thermal performance in Australian homes is an urgent priority to ease cost of living pressures, improve occupant wellbeing, and reduce energy consumption and emissions. So says H2: Opportunity Assessment Enhancing home thermal efficiency, a new RMIT University-led report, commissioned by RACE for 2030.

The report assesses current challenges related to home thermal efficiency improvements, as well as how to overcome these challenges to improve the homes and help Australia reach its target of net zero by 2050.

Thermal efficiency as a selling point

Despite growing awareness about efficiency, real estate listings still routinely omit information about features such as double glazing in favour of aesthetic drawcards such as “stone benchtops” and “mirrored splashbacks”.

Lead researcher and Inaugural Director of RMIT’s new Post-Carbon Infrastructure and Built Environment Research Centre, Professor Priya Rajagopalan, agrees that thermal performance of a home is often overlooked, with factors such as cost, design, location and convenience considered more pressing to builders – and buyers.

As for how to change that, she says that although having a thermally efficient home can save money, it’s vital to talk about more than the economic benefits.

“We need to look at the holistic benefits,” she says. “The health and productivity benefits – how effectively you can do your day-to-day work, and how does it impact your overall wellbeing?”

Rajagopalan says it’s also important to have a benchmarking system, so owners and buyers can meaningfully compare the performance of two different homes.

Ensure design matches reality

The National Construction Code sets minimum standards for building designs. But Rajagopalan says more needs to be done to make sure homes are built to spec.

“Often what is designed in the software doesn’t translate fully in the real setting,” she says. “Improved training of all trades, highlighting the consequences of poor construction practices, is essential to make sure they are delivering as per the specifications. There might also be unexpected air leakage or moisture entry in the physical build that the software is unable to predict.

“So not only do we need to make assumptions in rating tools as close to reality and involve thermal assessors earlier in the design phase so they can point out issues before it is too late, but we also need to ensure that what is designed is then actually built.”

Key to this, says Rajagopalan, is helping trades to upskill. But she acknowledges there is a perception that any change from business-as-usual practices will add costs, time, and complexity to projects. This perspective has resulted in an industry typically reluctant to adopt change.

“We need to find more creative ways of training those trades who are involved,” she says, “including training that can be fit for the future and helping them understand the consequences of poor construction on thermal efficiency.

“Maybe we need to scale up the delivery of training that include practical installation issues, and even make continuous professional development mandatory.”

Ramping up retrofits

The report also highlights the importance of improving our existing building stock. Australia has 10 million existing homes, most with poor energy and thermal performance.

Rajagopalan says government assistance is urgently needed in designing and rolling out an affordable thermal performance assessment program to start the retrofitting process of existing homes. Although there is a lot of information on how to improve thermal efficiency, it is hard to know where to start. And many professionals will naturally begin by addressing the problem from their own area of expertise, rather than taking a holistic approach.

“You can buy more energy efficient lights and appliances for your home, but it’s trickier and more expensive to retrofit a home to be more thermally efficient,” she says.

A potential solution is creating a “one-stop shop” for retrofitting homes, detailing the benefits of a thermally efficient home from verified sources.

“That would include doing the assessment and also providing recommendations for the potential upgrade information,” says Rajagopalan, “like what is the best solution for a particular house, as identified from the assessment.

“They could also help get quotes for the retrofitting, provide guidance on financial support, apply for grants on behalf of homeowners, make sure the works are completed on time, and also do a post-retrofit verification.”

Rules for rentals

Another area where Rajagopalan says governments have a leading role to play is in establishing higher standards across the country for rental homes.

International examples already exist and we are starting to see small changes locally. Victoria has introduced basic standards for rental homes that included window coverings, adequate ventilation and heaters with at least a two-star rating. In the ACT, all rental homes are required to have at least R5 insulation in ceilings, which can help retain heat in winter and reduce heat entering in summer.

“Effective policies that improve the thermal performance of over three million rental accommodations across Australia can contribute to easing the deepening housing crisis and help towards improving the quality of life of residents, majority of which are lower income population,” says Rajagopalan.

“We need to make sure the public know thermally efficient homes have significant health, wellbeing and social benefits, as they are not talked about enough.

“It might even put some pressure on designers, builders and policy-makers to build better performing homes and roll out retrofit program for homeowners and renters.”

Efficiency and wellbeing

Thermal efficiency can certainly improve health and wellbeing by maintaining comfort – as a recent Sustainability Victoria study showed. It’s not all about sealing and airtightness, however. Rajagopalan notes that good indoor air quality is also crucial.

“Ventilation is really important,” she says, “but the balance is quite tricky to get. It often depends on the behaviour of the occupants for things like opening windows and using exhaust fans while cooking and taking showers. As the envelope becomes tighter, you really need active ventilation supply to control indoor pollutants for better air quality.”

The research was led by RMIT University in collaboration with CSIRO and Climate KIC Australia.

The full report is available at the RACE for 2030 website.

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