Image from Steele Associates

Although divisive for some, Passive House (Passivehaus) is now proving its worth as a sustainable and high quality housing and building system that can work well in Australian climates. I had the opportunity to stay one night in Australia’s first Passive House Certified apartment building, The Fern, which was recently completed in the inner Sydney suburb of Redfern.

The 11 one-bedroom apartments are the work of Oliver Steele, who is the architect, builder and developer in this instance.

There’s a tall green wall that greets you on entry, and a further nod to biophilia with tactile timber handrails and finishes on the exposed concrete staircases.

The first thing I noticed when entering the apartment was how fresh and clean the air inside was, far better than any apartment I’d ever been in before.

The other thing I picked straight away was the quiet. You can hear the busy four-lane motorway on the street below, but it’s a hum rather than a roar.

It was an unseasonably warm evening, considering it’s only the first week in September (eek), but the interior of the apartment remained a very comfortable 20-24 degrees Celcius the whole time.

Good air quality, comfortable temperature and soundproof interior are features you can expect from all Passive House buildings, along with the less perceptible benefits of low energy use, no pollen (great for those with allergies), no pollutants (including toxic dust particles from car brakes) and no unwanted insect visitors (unless you welcome them in by opening the doors and windows).

All these features come down to the extreme airtightness of the building – something that’s confronting for some in the Australian construction industry because people are taught that “buildings have to breathe” (It’s also worth noting that passive house specifications and calculations are adapted for the local climatic conditions, and won’t pass certification unless they are met).

A few gaps here and there indeed allow fresh air into a building, which is important in Australia’s hot and humid climatic conditions. This works well to a certain point but if you can actually control what air is flowing in and out, then that can be even better.

Key to Passive House is wrapping a vapour permeable membrane and thick blanket around the whole building so it’s insulated and airtight. This is paired with a heat recovery ventilation system.

This system is pretty simple really and needs very little energy to run. It brings constant fresh air into the living areas and bedrooms and exhausts air from the bathrooms and kitchens.

The air coming in flows past the air going out without mixing physically, but the heat (or cool) is drawn from the stale air to the cold air, which is then fed back down into the pipes and into the rooms. The stale air, without the heat or cool, is then funnelled back outside.

The other critical aspect of Passive House is avoiding any thermal bridging, where there’s penetration of the building envelope for pipes or cables, or between the windows and doors, allowing the transferral of outside heat from the exterior building mass into the interior.

The Fern relies on seamless concrete to create an airtight seal (other materials can be used in timber homes though), which remains largely exposed as part of the design. The concrete finishes are complemented by natural materials such as herringbone timber floors, marble benchtops, and stone bath and basin.

Another important component of Passive House is sealable doors and windows. If you’ve been to Europe, you might have seen these high quality contraptions that make a satisfying click in and out of the seal when opened and closed.

These airtight windows are common in Europe.

These ones have been imported from Europe and weren’t cheap. But the hope is that once the building standard becomes more common in other parts of the world, these parts will be manufactured closer to home and at a lower cost. The rise of the building method in China suggests inexpensive Passive House componentry might not be that far away.

A sound night’s sleep

As someone who sleeps in a bedroom next to a busy road in your average leaky Sydney terrace house, the undisturbed night’s sleep was a real treat. I woke up feeling incredibly refreshed, despite sleeping in a room with the windows closed.

Another misconception with Passive House is that you need to keep the windows and doors closed at all times. But these buildings are also built for cross ventilation, so if you want fresh air you can “see”, you simply open the windows and doors and let the outside in.

It’s not like living in a sealed box. You can open the windows if you like.

There is a small airconditioning unit because passive house dwellings in temperate climates use them for the hot, humid days at the peak of summer to maintain the narrow thermal comfort range.

At the Fern, the systems use just 350 watts, which is enough to cool the entire apartment even during heatwaves and should only need to go on for half an hour or so at a time.

You perhaps wouldn’t notice the fresh air and temperate conditions if you didn’t know to look for them. But the whole notion of comfort in a home is, after all, largely the absence of discomfort.

Passive House might not be the only way to build sustainably but it ticks a number of boxes. On this tricky site, where the optimal orientation wasn’t possible due to a tall building blocking to the north, the Passive House method seems to have been a successful tool in the development of comfortable, low energy homes.

Image from Steele Associates

Join the Conversation


Your email address will not be published.

  1. These energy efficient windows uPVC or Thermally broken alum must be a standard here!!! There are more then 150 local manufacturers already. But wait Ask yourself a question, Why there is no Energy rating on windows in Australia? Is it because every one loves single glass alum windows or Love to struggle from the noise in an apartment build to the busy road? Oh love to use heater or air condition none stop?

  2. Numerous companies build and design these windows in Sydney and Melbourne. I am the Operations Manager at a company called Windows Factory and we specialise in these windows. They are the future of Australian building and far outweigh aluminium in all aspects from livability to aesthetics.

  3. These UPVC double glazed windows are available from numerous companies in Sydney and Melbourne. Locally manufactured to Australian conditions! I am the Operations Manager for the Windows Factory who specialise in these windows/doors. If anyone is interested in having a quote made up, contact me on 0402 481 775.

  4. Thermal bridge is the transfer of energy across a high conductivity building element. This is wasted energy.
    Thermally broken (thermal break): A piece of low conductivity material incorporated to prevent thermal bridging in window and construction systems.

  5. Hi, thanks for your comment. If I understand correctly I think there’s been a misunderstanding of the term thermal bridging. When you have a thermal bridge there’s an element or location providing a path of least resistance (a “bridge”) for heat to move through the building envelope. So you want to try and stop thermal bridging, not allow it, in a Passive House. Also it does mention that in the Sydney climate, heat waves can be too much for the ventilation system, and that’s why there’s a small airconiditoning unit to ensure comfort at those times (apparently should only need to be turned on for short periods to bring the internal temp down). I hope that all makes sense, happy to chat further if not.

  6. Dear Poppy,

    I am surprised to hear that Passive House avoids thermal bridging which in Europe, all the window systems are thermally bridged. to keep a constant temperature, I would expect every façade element to be thermally bridged so the heat and the cool doesn’t get transferred easily so that it will maintain a stable temperature internally.

    On a nice Sept month, most home are fairly comfortable.
    I would love to hear an experience of a stay on the top floor of the fern apartment in a heat wave.