There are a lot of things to love about Melbourne, but the changing weather isn’t always one of them.
Unlike the majority of Australia, which is dominated by sunshine and heat, anywhere south of the 35th parallel, including Melbourne in Victoria and Hobart in Tasmania, is at the mercy of the southern ocean’s weather patterns that deliver Antarctic blasts and cliff-like plunges in temperature.
For people new to Australia, the sudden cold in a place otherwise known as the “sunburnt country” can be a shock – but the shock is less to do with the outside temperature and more to do with how it feels indoors.
“I’ve never been so cold in my life,” some will say, adding incredulously that “the windows only have one pane and there’s an inch-high gap under all of the doors”.
I don’t know where the term ‘glorified tent’ originated, but that is what many think of our Australian housing.
Perhaps the poor insulation of our cooler climate homes is the result of being on a continent dominated by warm weather, where airflow and big windows make sense. But whatever the reason, the reality is our housing performance lags behind most other comparable countries.
As far back as 2005, our research for the Australian Greenhouse Office showed that Australia’s then Five Star minimum standards were actually about Two Stars below the equivalent standards in the UK, US and Canada.
And Europe is miles ahead.
High performance standards like the Passivhaus (Passive House) Standard in Germany, Minergie in Switzerland and Réglementation Thermique 2012 in France, that have been around up to 30 years, aim to improve the design of houses and their passive temperature control, rather than relying on artificial heating and cooling.
In many cases, the winter performance of these buildings is now so high that the current problem they face is, in fact, overheating.
So, if you have a coffee-like addiction to your heater, it’s a pretty good indication that the house you live in isn’t designed to deal with the cold, unlike a Northern Hemisphere house that boasts thick insulation, tight air seals and high-performance glazing including double and even triple glazing.
And while it is possible to achieve warmth with a big enough heating system, this is inefficient and expensive, and the pleasant comfort disappears as soon as the heater is off, leaving you with cold surfaces, cold draughts and a hankering for wearable doonas.
The more sensible option instead is to improve the performance of the building itself, with the goal of preventing heat loss through the building materials including through the window panes, door gaps, exhaust fans, fireplaces, down-lights and plumbing penetrations to name a few.
And passive design and construction principles work both ways – by making your house better insulated to keep in the heat during winter, you also make it more efficient at keeping cool during summer, especially if efforts are made to better shade windows and other glass areas.
Any new dwelling in Victoria (and most of Australia) is required to achieve a now minimum Six Star energy rating.
Despite the ongoing criticism that this minimum performance standard is too low and misleading, there is a significant difference between comfort in an older existing house that by comparison probably achieves Zero, One or Two Stars, and this new standard.
But it isn’t wise to rely on the Six Star minimum standard when having your new house built, as there is a lot more that can be done to ensure heat loss is minimised further.
If possible, request that the designer or builder identify what would be required to increase the star rating to Seven or Eight stars and investigate any additional requirements to achieve passive design measures, including meeting the Passive House standard, where heaters are only infrequently used.
And it’s not just about the design of the house, it’s also about the the construction’s quality and attention to detail that makes all the difference.
If you are renting, the chances are you won’t put a screw in a wall to hang a picture let alone make changes to the thermal properties of the building.
Fortunately, Victoria recently introduced the Rental Tenancies Act in 2021, which rules that all homes must have a fixed heater in the main living area by March 2021 (and a Two Star minimum heater by 2023). This is a clear indication of how poorly heated some rental houses have been up until now.
The installation of reverse cycle air-conditioning (as the new law requires from 2023) is far superior from an energy performance perspective compared to an old inefficient electric resistance heater like an oil one (as required from now) – but it won’t keep the house warm when it’s turned off.
The new law also prevents landlords from refusing requests from tenants to make minor changes to the property to improve winter performance.
Although still in trial phase, the Victorian Residential Energy Efficiency Scorecard is a new program in which an assessor can visit your house or rental and suggest upgrades to improve its performance.
An unfortunate side effect of sealing buildings to improve comfort in cold environments in an increase in indoor moisture which can lead to condensation and mould.
This is a very serious health problem that must be avoided. Common sources of excess moisture include showers, cooking and un-vented clothes dryers.
One way to ensure ventilation while keeping a house warm is to install a heat-recovery ventilator that draws in fresh air, warming it with the heat of the vented stale air.
But there is no good reason why us Australians down south streaming our favourite shows during winter need feel colder than people doing the same in Helsinki or Tokyo.
It’s time to wake up and see that while we might be the ‘lucky country’ in many ways, we aren’t lucky with our housing.
We need to think smarter when it comes to protecting ourselves from the extreme temperatures that a combination of geography and climate change are sending our way.
Dr Chris Jensen is a certified passive house tradesperson.
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