As winter begins and temperatures plummet, it can sometimes feel as cold inside as it does outside. The reason for this is the poor thermal performance of homes in Australia. Our homes need to be improved quickly to combat climate change, tackle energy poverty, and improve our daily lives.
Minimum energy and comfort building standards in Australian homes lag far behind in many regions. Fifty years ago, it was the oil crises of the 1970s that triggered the creation of building energy standards in Europe and North America, and a widespread shift to double glazing, increased insulation and concern. for energy efficiency. In Australia, it was not until the 1990s that minimum insulation requirements emerged. Only in 2003 did the Australian Building Code set energy efficiency standards for homes across the country.
The performance of our homes is governed by the National Household Energy Rating Scheme (NatHERS for short). Scores range from 0 stars, for a house that would not provide any climate protection, to 10 stars, where virtually no year-round heating or artificial cooling is needed. The current minimum yield for new homes is 6 stars, which has been set since 2011. However, the average Australian home is only 1.8 stars. Maybe it’s closer to a tent than a modern eco-friendly home.
Australian housing leaves much to be desired in terms of comfort and energy. Single glazing is still typical, while in Sweden double glazing has been required by building codes since 1960, with triple glazing now the norm in many colder climates. Australian homes are also leaking. Older homes can have a “tightness” of more than 30 shifts per hour, meaning all the air inside will come out 30 times every hour at 50 pressure pascals. In newer homes it is closer to 10-15 air changes. In comparison, a high-performance “Passivhaus” benefits from 0.6 or fewer air changes per hour. For many of us, we are paying thousands of dollars a year to heat our homes, just so that this heat escapes directly through the gaps in the walls.
What is the impact of this? Very high bills to begin with. 2015 estimates suggest that around 28% of Australian households suffer from some form of energy poverty, ie they struggle to pay their energy bills or restrict their use of energy to the detriment of their health to maintain. -the affordable ones. While the energy price spiral is the engine, leaking, uninsulated homes can increase the effects. Take a 180 square meter house in Canberra. If it received a 2-star NatHERS rating, it would need 27,349 kWh of electricity. If we assume $ 0.20 / kWh, the cost would be $ 5,470 per year. A 6-star house would need $ 8,249 kWh and cost $ 1,650, while a 10-star house would need only $ 100 kWh, at a cost of only $ 20 a year.
The most vulnerable feel the effects more intensely. UNSW research found indoor temperatures in social housing as low as 5ºC in winter and up to 39.8C in summer. The health impacts of this go beyond being uncomfortable, with cold homes related to high blood pressure, asthma, poor mental health, respiratory and cardiovascular disease.
There are two solutions to this crisis. First, we need to significantly tighten our building standards. Why is this important? We know that more than three-quarters of new homes are built with only the minimum performance requirements; few surpass that. The good news is that Australian regulations will increase the minimum performance from 6 stars to 7 from September. Although this is a start, we are still behind the EU, where all new buildings have to achieve almost zero energy efficiency: they are buildings that require very low amounts of energy.
However, improving our new homes may be the easy part. The second solution is that we need to radically renovate our existing buildings.
There are some DIY options: insulate ceiling spaces, seal gaps around windows, and more. But for significant energy savings, we need to carry out “deep renovations,” that is, systematically improving walls, ceilings, floors, and windows while installing highly efficient ones. heating and cooling systems. This can require a lot of work and subsequent expenses. The recent refurbishment of Little Loft House in Canberra increased energy efficiency from 3.8 stars to 7.7 stars, at a cost of $ 400,000.
Achieving this at the national level would require significant government support, focusing first on the most vulnerable: social housing, people with disabilities and the elderly. Perhaps we can look at Italy, where the recent 110% super bonus scheme allows homeowners a tax credit of up to 110% of the cost of home refurbishment.
There is no place like home, at least as the saying goes. But if this house is cold, flowery, expensive to face and unhealthy, it can also be an incredible source of stress, discomfort and cost. We have the opportunity to improve it by tightening our building regulations and completely renovating existing homes. We have been behind much of the world for too long.
Philip Oldfield is head of the UNSW School of the Built Environment and a researcher in sustainable, low-carbon architecture.