Surprising housing trend saving Aussies 20 per cent on their bills

A surprising theory has emerged that two items now commonly used in the construction of Aussie homes are creating an unintended cost-of-living win. The two materials are believed to be resulting in a huge 20 per cent less heating and cooling requirements.

The idea stems from a survey by our national science agency the CSIRO of 233 apartments and detached houses built over the last four years in Melbourne, Sydney Canberra, Brisbane and Adelaide. It found these new-build apartments are 50 per cent more airtight than those tested in 2015.

The CSIRO’s senior experimental scientist Michael Ambrose explained that most energy is spent trying to heat or cool a home, and when it’s properly sealed, residents can expect their bills to drop by a fifth.

“Making sure when we’re cooling or heating that we retain that conditioned air inside our homes is really important,” Ambrose told Yahoo News. “And vice versa — it's actually also important that we don’t have hot air in the middle of summer getting into our buildings.”

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What is the first change causing a drop in electricity usage?

Ambrose said his colleagues expected to see an improvement over the last nine years, but because there haven’t been “significant changes” to the relevant building codes, the results of their Air Infiltration of New Dwellings in Australia survey surprised them.

They put some of the change down to improved building methods and better seals around doors and windows, but it was the inclusion of two new items in particular that stood out.

“This was a dramatic improvement in air tightness. But to be absolutely honest we can only speculate as to why improvement has occurred,” he confessed.

“We think it’s been driven in part by building wrapping — if you look at new construction sites they all have that blue wrapping around them. It’s become very common now but we didn’t see it nine or 10 years ago. It’s mainly meant for water proofing, but it does act as an air barrier as well.”

What is the second change?

The second change in the construction of homes is the lighting we use in our ceilings. While halogen downlights used to be all the rage, they’ve now been phased out with more energy efficient alternatives.

“They needed lots of ventilation because they got quite hot. But they’ve been replaced by LED downlights. These are completely sealed units and because they don’t get hot we’re able to put ventilation over them,” Ambrose said.

“We tested individual light fittings and found virtually no leakage through them.”

Better homes create new problem for homeowners

While the improvements created an “unplanned good news story” for the environment and the hip pocket, they also create a new problem that can be a danger to human health.

But before you worry that your home might be unsafe there is a fix for it.

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“You may have heard that people in new apartments have complained about condensation problems and getting mould. And a lot of that is due to poor ventilation that is going on in these apartments,” Ambrose explained.

“When you've got reduced air, you can have Co2 levels increase in there as well.”

The way to get around the problem is installing a controlled ventilation system that enables fresh air to come in from the outside.

“We think they’re going to be really important. And something that needs to be in the regulations as well.

“We don’t want to see holes in our buildings again. We just need controlled ventilation systems in them.”

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