Consider thermal mass of new home new builds

January 9, 2020 BY

Brendan Condon’s super-sustainable home at The Cape where 7.5-star energy ratings are the starting point. Photos: SUPPLIED

As Australia enters the peak of summer, which has already seen black outs and dangerous heatwaves, homebuyers are being urged to consider the thermal performance before committing to a home design.


Villawood Properties executive director Rory Costelloe believes that designing houses that are truly 7.5 to 8-star is the path the industry needs to take.

VILLAWOOD Properties executive director, Rory Costelloe, said that both builders and consumers needed to look beyond energy and water saving technology in order to bring new homes to the standard necessary to cope with the consistently increasing average temperatures across Australia.

“The maximum temperature has been increasing over the past few decades and it looks like we’re going to get record temperatures this summer,” he said.

“It is quite conceivable temperatures will reach 50 degrees soon, if there’s a major blackout, it’s a real possibility that people will just perish.

“It’s not just a matter of using less energy to warm or cool house, it’s about personal safety, particularly for older and immobile people.

Mr Costelloe said that a truly sustainable home needs to look at more than just saving power.

“Currently, everyone’s focusing on designing energy efficient houses to save electricity but with these really high temperatures coming for extended periods, it is becoming really important to have a properly thermally designed house,” he said.

“The average six-star house probably doesn’t perform truly at six stars as they are not properly tested.

“Having seen what some pioneers are doing, particularly at Cape Paterson, where they are using a fraction of the energy use of an average suburban house, we believe that designing houses that are truly 7.5-8-star is the path the industry needs to take.

“A truly 7.5-8-star home has an indoor peak ambient temperature of around 24 degrees on a 40-degree day without the use of artificial, energy intensive cooling appliances.

“In addition, an 8 star-home uses an average of 51 per cent less energy of a 6-star home to maintain a comfortable and safe ambient temperature of 22 degrees.

With the addition of heat exchanges and better thermal performance, both of the outside cladding and use of thermal mass on the inside, a new home build can be even more sustainable.

“This will achieve a pleasant living environment, as well as a house that is safe for our young and our elderly, particularly in periods where you have days on end of extreme heat,” Mr Costelloe said.

“Within Villawood’s own projects, Aquarevo is leading the way and South East Water’s Aquarevo House is a great example of smart, sustainable design.

“In addition to the water and energy saving initiatives that are incorporated in all homes within the project, Arden Homes has designed Aquarevo House in such a way that the ambient temperature within requires little heating or cooling to remain comfortable.

With the increased likelihood of energy black outs now and in the future, 8-star homes with solar and battery storage with backup power from the battery during a black out is the safest, most comfortable way to live, and it is affordable.

“Even their first test case of zero net carbon building is still performing well three years down the track, with Arden’s Director Rick McKay reporting an internal temperature of 22.8 degrees, despite being 39 degrees outside,” Mr Costelloe said.

“This is without the assistance of air conditioning and if there is a blackout, he’ll be comfortable and safe from the heat in his zero net carbon Arden home.”