Sustainable House Day 2020: Why you should care about it

“It’s such a small thing for such a big payoff.”

That’s the nub of the message which Matt Luthi, who has built two 10-star energy-rated houses in the last six years, passionately wants to get across to the public who will participate in the annual nationwide Sustainable House Day on Sunday.

Forced online, as are so many other popular local and international events, the organisers of the 19th sustainable open house festival that examines all aspects of making residences energy-smart are hoping that while the number of houses (170) may be slightly down, the vamped-up virtual accessibility may see more people take part than last year’s 44,000 visitors.

With houses from around the country being presented via video and explained by their owners, and a conference-like agenda of 30 Zoom sessions, organiser Jess Dorney says the event “is an incredible opportunity to hear from the people who are doing it.”

She says the essential mission of the day, which has been staged yearly since 2001 by Renew, or the Alternative Energy Association, “is to just start somewhere. It’s not that hard!”

The Zoom sessions will consider all things from sustainable design to retrofitting, the operation of water and energy harvesting systems, from tiny houses to those built to mimic nature’s ways, and from earth buildings to prefabs.

Mr Luthi, a “Swiss hillbilly” and software designer who came to Australia 20 years ago, and who in the last decade decided he didn’t want to be yoked with a mortgage he could still be paying off at 70, designed and had built his first super sustainable family house at Beechmont in the Gold Coast hinterland in 2014.

Talking of himself as “just a person off the street”, he says the process “was not difficult”.

Deep research into best-practice materials, best building attributes and the funds needing to be outlayed led Luthi to reject things like straw bales in favour of a timber-framed, heavily-insulated, metal-clad house with perfect solar orientation because he worked out it would be half the build price of, say, rendered straw bale.

“Small at 150 square metres, it was a super-comfortable, high-quality house,” he says. When the all-but-off-grid home was officially energy rated, Luthi was surprised to discover it warranted an impressive 9.6 stars.

“I asked what I’d have to do to make it 10 stars and was told I needed to add an extra fan in the kitchen.” That was easy enough for a perfect 10.

With two children approaching high school and the prospect of long morning and afternoon parent-taxi commutes, Luthi and his GP wife decided to sell at Beechmont and move to the nearby village of Tamborine to start again.

Twenty minutes after listing their house on the internet they had a potential buyer champing to see it. Next morning “the first people who saw it bought it at the price we wanted”.

Having so adored their first self-made house, the family opted to repeat the design template, but make it bigger, make it on a steel rather than timber frame, and give it five bedrooms and more windows to see out to the remnant original rainforest bordering their block.

Acting as an owner-builder, Matt Luthi was able to bring potential builder/contractor quotations down from an initial $608,000 estimate to the actual $340,000 he ended up spending. “And that included a letterbox.”

He was also able to find and import highly specified “commercial class windows – 34 of them – from China”, in the process saving $35.000 from what was quoted for lesser-grade locally-available windows.

Although Tambourine House is linked to the grid, the service for the all-electric house is so little used that there are still no costs associated with running the home. In fact, excess power is sold back to electricity retailers.

And, for the second time, the Luthis have scored a 10-star energy rating.

At 44, Matt Luthi and his family reside in a bill-free, mortgage-free home “on a beautiful block”. The energy rating, he says, “is not just a badge of honour”. The bigger outcome “is to live in a comfortable house that barely needs any heating or cooling” and that helps the environment “because we all know that something is not right with our climate”.

Luthi, who will present in the 5pm owner-builder session on Sustainable House Day is out to inspire others.

“I’m happy to share my plans,” he says. “It’s such a small thing to make a house design and get it right and get it more efficient. It’s such a small thing with such a big pay-off.”

Access to the virtual tours and sessions is free and open on September 20. Associated events taking place before and after that date require registration via the www.sustainablehouseday.com