Housing: NAB backs Passive House without pre-sales, as quality wins
Sandra Edmunds | 13 February 2017
The triple-glazed doors and windows of Australia’s first Passive House apartment development will help create a quiet oasis right next to the hustle and bustle of Redfern train station.
Steele Associates director Oliver Steele says the 11 one-bedroom apartments of The FERN development would be sold on completion rather than off the plan.
“Passive House is a brand new concept in Sydney,” he says. “It’s hard enough to explain to someone who has worked in the industry, trying to really explain it to a buyer is just too hard … because Passive House is so different.
“So we have managed to get funding without the requirements of pre-sales, which is fantastic, so we can build them and then say, ‘Here you go; this is what it’s all about.’”
NAB has been very supportive of the project due to Steele Associates’ track record.
“And they can see that we’re onto something that is a high-quality sustainable development and they’re prepared to get behind it, which is a great help,” Steele says.
The benefits of the Passive House building standard include energy efficiency, comfort, affordability and sustainability. Amazingly, Passive House developments enjoy energy savings of up to 90 per cent compared with typical buildings and more than 75 per cent compared with average best-practice constructions.
Steele says the stand-out benefits for city dwellers are superior air quality and lack of noise.
“Here you will have a fresh, bright, quiet oasis and that’s the real difference to end users,” he says.
“Anyone who has lived in the inner city knows that if you open the window you get the noise and you get black dust… The real difference here is that you can have a perfectly climate-controlled interior with natural fresh air without the drying effect of airconditioning, with no dust and no noise, right next to Redfern station.”
In what Steele believes is a first for Sydney, the development will feature triple-glazed doors and windows. This is mainly due to the site’s orientation.
“Because of the nature of the site we can only get windows on the eastern and western sides. Sydney’s strong afternoon sun means we have to use triple glazing,” he says.
Work on The FERN development is underway. The building will be a full concrete structure and currently the concrete slab is being poured. The basement walls will be built in the next few weeks.
To meet the requirements of the Passive House standard, the Steele Associates team must eliminate all thermal bridges.
“Thermal bridges are where heat can transfer through the structure inside to outside,” he says. “So if you have a piece of steel travelling from inside a wall to outside a wall that conducts heat in and out very easily.” Traditional balconies that stand out from the building are a prime example.
Thermal bridges have the effect of unwanted heating and cooling as well as causing condensation and mould in the building’s structure. The team will use special stainless steel sheer connectors through PIR foam insulation panels to separate internal and external concrete, boosting the building’s thermal performance.
Another key requirement is eliminating gaps.
“We are completely air-sealing the interiors so we will be sealing all the joints and around all the doors and windows and then actually doing a door-blow effect on every apartment,” Steele says.
The builders will place an industrial fan at the front door of each apartment, seal it, and pressurise the apartment to 50 pascals. The dwelling is not allowed to have more than 0.6 air changes an hour to meet the Passive House standard.
In layman’s terms, for an average-sized three-bedroom house, the sum total of all gaps around doors, windows, the structure, even exhaust fans and vents, is allowed to be no bigger than the size of a business card.
“Most houses built to conventional standards now would probably have an A1 piece of paper in gaps in total around the whole house,” Steele says. “So it’s really another world in terms of air sealing.”
So you have these very well-sealed apartments but the inhabitants will need to be able to breathe. Therefore, a key feature of the Passive House standard is controlled ventilation using a heat recovery ventilation system.
“It gives you constant filtered fresh air 24/7 but, as it exhausts and intakes air, it uses a heat exchanger to make sure that we can keep the heat inside in winter and outside in summer,” Steele says.
No gas will be connected to the apartments. Instead, rooftop solar panels will provide electricity with the aim of making the building entirely self-sufficient.
“It will be connected to the grid as a back-up but the aim is if you cut the cord to the grid, you wouldn’t notice the difference,” Steele says.
Likewise, there’s zero car parking. Twelve bicycle spaces will be provided in the basement with lift access to the ground floor. In addition, every apartment will have a basement storage cage with room for a second bicycle.
“You won’t need a car if you live here,” Steele says. “There’s a shared car about a 100 metres from the site.” And, of course, Redfern station is moments away.