Ahead of Sustainable House Day, being held across the country on 11 September 2016, we’re taking a look at some of the best homes on display.
For an added spend of around $50,000, the engineering team leader for the award-winning Illawarra Flame house project, Michael Whitehouse, made his family home energy bill free without going off-grid.
The house in Wollondilly Shire’s Bingara Gorge Estate is net energy positive and utilises many of the techniques and technologies incorporated in the Illawarra Flame, he says.
They include a five kilowatt solar system that cost around $10,000, an evacuated tube solar hot water system at between $5000 and $6000, an air tempering system to pre-heat or pre-cool air entering the home through a natural ventilation system, high-performance glazing in framing incorporating thermal breaks, and additional insulation.
The house also has LED lighting throughout, and used low-VOC and sustainable materials including bamboo flooring. The site has a northerly aspect that he designed around, with a courtyard that traps the sunlight and warmth in winter. Wide verandahs shade the summer glare.
Overall, the five-bedroom, two-bathroom home cost around $360,000 to build as an owner-builder. Whitehouse says he did some of the work himself to keep costs down, including installing the flooring and doing the painting. He estimates that building a similar home using entirely outsourced trades and labour would cost around $500,000.
From the street, it looks like a contemporary country-style home, which was the idea, he says.
“Our whole aim was to build a house that is inherently sustainable and keeping it cheap,” he says.
“It is quite a simple home.
“The house is not overtly sustainable – you are not going to see all the technology from the street.”
Whitehouse says the technologies are also simple to manage. There is no building management system, and everything is automated including the solar power, hot water system, and heating and cooling. All the systems have a switch, and when on they operate as needed.
He has an energy monitor that lets him know what is on and when, and he says this is part of making the house work as it was designed to.
Along with the high level of thermal comfort reducing energy use, there is also the factor of how occupants live their lives, he says. In his home, people turn things off.
“We don’t pay energy bills,” he says.
The social aspect of sustainability
The social aspect of sustainability is important, he says. He completed research while working for Lendlease in its design team on the performance of homes and apartments after they were occupied, and it demonstrated that a lot of energy can be saved through how occupants use their houses.
There are other values the sustainability initiatives have added to his family’s home that he says can’t have a dollar value put on them, including the feeling of comfort and the degree of soundproofing the added insulation has delivered.
Whitehouse built the house around six months after the Illawarra Flame project, and found that some of the technologies such as solar PV had come down in price.
Other research-based initiatives used in the University of Wollongong prototype home are still not cost-effective in terms of using them in a regular home, he says.
“One of the classics is phase change materials. They are expensive, so phase change materials were not really cost effective to use [in this home].”
Instead, he added extra solar panels.
The most bang for buck
Whitehouse did an undergraduate thesis on the cost-effectiveness of sustainability technology in homes and where dollars can be most effectively spent. Solar hot water, extra insulation and thermally effective windows came out as the most strategic budget items, he says.
Everything he has used in the current home can be bought in the regular market place.
“If people come to this house and also visit Illawarra Flame [on Sustainable House day], they will get to see the full spectrum,” he says.
He and his family are now in the process of building another house on the Central Coast of NSW, and when it is complete the current home will go on the market.
“A lot of the things I learned doing this one I will apply to the next house,” Whitehouse says.
“There are things I think I can do better, such as increase the insulation in the internal walls.”
He is also looking at different suppliers for better window frames.
Another lesson is where insulation works best in the roof cavity. The heating and cooling system takes air tempered in the roof cavity, however as Whitehouse installed the insulation under the roof, the cavity is not getting as warm as it could in winter for effective pre-heating.
Next time, he will change the insulation location to the ceiling, he says. On the cool summer nights the Central Coast site experiences would also enable the cavity to provide naturally cooled air through the ventilation system.
Now running his own design company, Whitehouse says the majority of clients just want the cheapest outcomes.
There are opportunities in terms of architectural design to get better solar outcomes that will potentially reduce energy use and increase comfort, but people turn away from anything that involves spending a few dollars, he says.
Whitehouse says that while he expected this from the first home buyers, he is finding it can be a “hard sell” even to the “upgraders” – those looking to upgrade from a first or second home to something a bit more upmarket.
“I am hoping on Sustainable House Day I will be able to talk to a captured market,” he says. “People who are not just after the cheapest [they can get].”