Even with rooftop solar boom, households are paying dearly for what lies beneath | RenewEconomy

Even with rooftop solar boom, households are paying dearly for what lies beneath

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Australians have led the world in solar installations on their rooftops, but lag way behind in terms of what they do under the roof. And it’s costing them dearly.

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Image: The Cape
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One Step Off The Grid

Australian households have led the world in their uptake of rooftop solar, but a look under those rooftops tells a starkly different story.

Thanks to a combination of historically cheap energy and a largely forgiving climate – particularly in the winter months – Australia has put little stock in the importance of thermal efficiency in homes, or in energy-smart and environmentally sustainable building in general.

But as the climate has become less forgiving, and electricity more costly and unpredictable in price, Australian building standards have hardly budged.

“We’re lagging between 10-15 years behind in Europe, parts of US and Canada,” says Trivess Moore, a senior lecturer in construction at RMIT and member of the Sustainable Building Innovation Laboratory.

At the same time as Australians are embracing rooftop solar technology to reduce their consumption of electricity from the grid, research shows more than 80% of detached housing in Australia is built to minimum regulatory requirements – currently 6.0 stars on the Nationwide House Energy Rating Scheme.

“We have a long history in Australia of delivering pretty poor quality housing in relation to thermal efficiency but also in broader sustainability terms,” Moore told One Step Off The Grid in an interview this week.

Moore, who has been researching this subject for the past decade, says there has been an ongoing – and frustratingly immutable – challenge to introduce and improve building standards in Australia.

But the good news is that aiming just a little higher on thermal and energy efficiency in new homes can yield significant benefits – for households, for the grid, and for Australia’s emissions reduction task.

A recent study by Moore and his team at RMIT found that for Victorian homes designed to a minimum of 7.5 stars, the energy required for heating and cooling amounted to 40 per cent less over the course of one year than for a 6-star house.

“What we found in the interviews with households is that they were using their air conditioning systems (much) less… turning them on only on a handful of occasions across summer and winter as they felt the homes performed well enough with some active thermal comfort actions such as opening and closing blinds and windows,” the report says.

The study highlighted numerous benefits of this improved thermal efficiency performance, starting with the reduced energy costs that result from such a significant reduction in energy used to maintain thermal comfort.

A second benefit is that these homes spend a greater percentage of the time in the healthy temperature range (without the need for mechanical heating and cooling), which had the potential to improve health outcomes for occupants.

Thirdly, if there is a blackout, the homes can still maintain thermal comfort for an extended period of time. And finally, it means the homes can use smaller heating and cooling appliances (or remove them altogether) reducing capital, maintenance and replacement costs over the life of the home.

The study was based on the performance of actual homes built as part of an all-electric, highly energy efficient housing development on Victoria’s Bass Coast, called The Cape.

These residences in the coastal town of Cape Paterson were the brain child of Brendan Condon who was increasingly confronted by the poor standard of Australia’s housing stock through a previous role in biodiversity management on housing estates.

“It quickly became apparent to me that we can actually step up and build much more efficient and resilient housing, by training our builders and designers and consulting with energy efficiency experts.”

And this is what he did. Houses at The Cape are built to a minimum rating standard of 7.5 stars. They are also built to be all-electric – including electric vehicle chargers in the garage – and with a minimum of 2.5kW rooftop solar for each house.

“Initially it takes a lot of rethink and effort to step up,” he said. “But once you’ve done that it becomes part of normal building practices to effectively seal homes and insulate then to a high standard.

“We found that builders were able to easily able to achieve 7.5 stars,” Condon aded, noting that in most cases, if they aimed for 7.5, the houses often wound up achieving an even higher thermal efficiency rating, anywhere between 8 and 10 stars.

This is borne out in the RMIT study. “The Cape set out a minimum requirement of 7.5 stars, but what’s being delivered is much better,” said Moore.

“The average is 8-8.3 stars, and so the next level of performance being delivered.”

And the feedback from the home owners is all good.

“It’s not unusual to have residents texting me their bills, showing that they’re close to zero, or even that they’re receiving income for their solar power,” Condon told One Step.

So why aren’t we all building houses to this standard?

According to Moore’s past research, resistance to higher standards for home thermal and energy efficiency has been predicated on the industry-based argument that consumers – and not regulation – should drive the market.

But so far, this has not happened. “The building industry is hesitant to support increased changes to regulation and often talk about it adding cost for the consumer,” Moore told One Step.

…To read the full story on RenewEconomy sister site One Step Off The Grid click here…

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