The Most Sustainable House

I wheel my bike across a small boardwalk toward the house amongst the shrubs. Yes, this seems to be the one — it looks just like the tiny model that I saw a few days earlier, except life-size. In my hand is the key; the place is mine for the night.

First I walk around the outside, exploring what makes it so special. In many ways it looks like the fibro shack that it once was, except with some modifications. It’s hard to believe that it’s travelled to China and back and been assembled three times. Even more incredible is that it’s apparently one of the most sustainable houses in the world.

A few days earlier I had pedalled my way onto the University of Wollongong‘s (UOW) north east campus, down ‘Innovation Lane’ and up to the Sustainable Buildings Research Centre. It was an impressive multi-storey structure, all wood, glass, steel and rammed earth, bedecked in solar panels and with a large annexe out the front. I rolled my bike into a courtyard surrounded by gardens and reed beds. Soon Robyn appeared and took me to their special bike enclosure around the side.

Robyn is the administrator here, and specialises in translating the jargon of the academics and researchers into a language that laypeople can understand. She began telling me about the Centre as we headed inside for the tour.

A wall of greenery cascades down a two-storey wall in the main atrium, apparently to help cleanse the air and improve occupant well-being. From hydronic heating circuits and geothermal heat pumps to daylight harvesting technology and an advanced building management system, the building seems packed full of sustainability features. There’s even a vege garden on the rooftop that’s tended by the researchers.

The first 6 Star Green Star building in the Illawarra region, the Centre was created as a world-class facility for carrying out research in sustainable buildings. There are other similar research centres around Australia and the world that they collaborate with, and sometimes even compete. Robyn told me the story of one such competition which has had a huge impact on the Centre.

It started in the U.S.. The Department of Energy noticed that, unlike with commercial buildings, there didn’t seem to be much driving sustainability innovations in residential houses. They decided to change this by holding a competition: to design and build the most sustainable house. It became known as the Solar Decathlon, with the entrants being judged in ten categories, including energy performance, comfort, operability, financial affordability and market potential, to name a few.

It became a biennial event, with colleges around the U.S. taking part. It soon expanded internationally, with Solar Decathlon’s hosted by Africa, Europe, Latin America and the Middle East. In 2013 it was to be held in China for the first time, and a team of students from UOW submitted an entry. They called their design the ‘Illawarra Flame House’, named after a well-known tree native to the area.

Robyn takes me to the Centre’s large foyer where a number of displays have been set up. She leads me over to a glass box on a pedestal containing a scale model of a house, complete with miniature trees and shrubs surrounding it.

The UOW team was the first from Australia to gain entry into the finals of a Solar Decathlon, and it was the first time in Solar Decathlon history that a ‘retrofit’ design was used.

Typically when planning a sustainable house, most people opt to build new — starting with a clean slate, the sustainable design features can be included from the start. But the UOW team were conscious that there are a lot of existing houses out there that could be reused and upgraded, to save resources and eliminate the waste associated with the demolition of older homes. They chose to retrofit a typical Australian ‘fibro’ house, one of the most common and least energy efficient houses in the region. Their thinking was that they could showcase a blueprint for transforming existing houses into stylish, affordable and sustainable homes for the future.

A fibro house was obtained, re-assembled on the university campus and retrofitted with the new design features. It was then dis-assembled, packed into shipping containers and sent to China for the competition.

Back on campus, I’m circling the outside of the Illawarra Flame House, checking it out. There are modifications from the original fibro box that I can see, such as the offsetting of the roofline to allow a row of ‘clerestory windows’ at the apex that provide light and ventilation. Outdoor decks have been added on both sides, both shaded by annexes that jut outwards from the house like wings. Pods have been added as prefabricated extensions to the original bedroom and bathroom.

Around the house are native gardens and reed beds, with a pathway made from crushed terracotta roof tiles winding through it, and ramps made of reclaimed timber extending up to the decks.

But apparently there’s more that I can’t see. Seeing solar panels on the roof comes as no surprise, but apparently there are two different types: high efficiency polycrystalline panels, as well as some thin film panels for diffuse light. I can see the tank for harvesting rainwater, but there’s also a specially constructed reed bed and slow sand filter that’s treats the house’s greywater, for re-use in irrigation and clothes washing. All up, the house is net zero energy and net zero water.

Robyn explained that the narrow space underneath solar panels can become very warm, so they’ve taken advantage of this by designing roofing sheets with internal channels that transport the warm air upwards, to be released either outside or inside, depending on the needs of the house.

There are planter boxes on a wall on one of the decks for a vertical vegetable garden, and an aquaponics and compost system behind it for growing fish and reducing household waste — though these don’t seem to be in use at the moment, perhaps needing a longer-term tenant.

I wheel my bike up onto the back deck and finally enter the house, carrying my bags through to the bedroom. Inside it feels like a normal, comfortable and stylish beach house. The furniture is all made from reclaimed or recycled materials, like a lot of the house, and has a retro feel to it. I go exploring the different rooms: a living-dining-kitchen area, a large bedroom, a study with a foldout sofa, a bathroom and a laundry corridor. It was apparently designed for older couples nearing retirement — ‘empty nesters’ whose children have moved on.

The whole house is controlled by an advanced building management system to monitor energy usage and regulate the temperature as efficiently as possible, prioritising natural ventilation. There’s a lot of natural light, and I can see how, with outdoor decks on either side, the doors can be opened up to let the breeze blow through. Not that I want to do that at this time of year.

I discover a system display panel on the living room wall that says it’s currently 20.8 degrees. It’s a cold evening in June, and there are no heaters on.

I try to remember the features Robyn told me about that make this possible. There’s the insulation in the walls and ceiling, the double-glazed windows, and all the gaps, drafts and heat leaks have been sealed up. There’s also a thick wall between the living area and the bedroom that provides thermal mass — the idea being that it takes a lot longer to heat up and cool down, thereby keeping the house at a more constant temperature. It’s apparently made from 90% recycled content, including terracotta roof tiles from the original house.

Beneath the floorboards lies a clever feature that I’m intrigued by. Robyn explained the ‘Phase Change Material’ thermal store, essentially blocks of a special wax with a melting point around room temperature. It makes use of ‘latent heat’ — similar to how your sweat absorbs some of your body heat as it evaporates, the wax absorbs heat as it melts, and releases it as it solidifies, thus helping to regulate the temperature of the house.

I go to turn lights on in the different rooms — all LEDs, of course — and find myself confronted by many buttons on a small control panel in each room, each button activating a light or opening a window somewhere. There are also sensors in each room, and the internal lights dim automatically based on occupancy or natural light levels.

I wish someone had given me a manual or something, as I keep opening a window by mistake. This house is clearly more sophisticated than I am, but I imagine I’d get the hang of it eventually.

After six weeks at sea, the Illawarra Flame House arrived in the city of Datong in China. The UOW team were able to re-assemble the house in less than ten days, ready for the ten-day competition period. Over 300,000 people visited the Solar Decathlon site, and more than 35,000 people were toured through the Illawarra Flame House — one visitor every eight seconds. The team was examined by five ‘juries’ of international experts, and were made to carry out many competition tasks that tested the practical use and performance of the house.

The Illawarra Flame House came first place overall, ahead of 19 other teams from around the world. They received a total of 957.6 points out of a maximum of 1000 — the highest ever overall score in any Solar Decathlon competition.

The house was then transported back to Australia and re-assembled on the UOW campus, to be used for ongoing research and education, and as a test-bed for new technologies and systems. When Robyn told me it might be possible for me to stay a night in it, I became determined to try and make it happen.

The Solar Decathlon was held in China again in 2018, and again a team from UOW made it into the finals. Robyn took me over to another glass display case with a scale model of a house: the Desert Rose. She told me that the full-size house is still in shipping containers on its way back to Australia, where it will be re-assembled alongside the Illawarra Flame House. There will probably be future Solar Decathlon houses created by the university. The plan is to re-assemble them all here on ‘Sustainability Street’, where they’ll form a precinct of ultra-sustainable and inspiring houses; a place to demonstrate the latest in innovative building and sustainable living.

Inside the Illawarra Flame House, I make dinner and settle in for a relaxing evening watching a cheesy rom-com on TV. I find myself wondering: what should a sustainable house feel like? Things like energy and water efficiency aren’t really felt until the bills arrive.

I head to bed early with the nice warm feeling that comes with being in a comfortable home designed to have a tiny environmental footprint — one of the most sustainable in the world.

Huge thanks to Robyn Dawson for showing me around the SBRC and patiently dealing with all my followup phone calls to arrange a night in the Illawarra Flame House.

Thanks for following my journey! Can you donate to help keep me pedalling forwards?