Frost inside? That’s because Australian homes are more akin to tents than detached eco-buildings | Philip Oldfield

AWhen winter sets in and temperatures drop, it can sometimes be as cold inside as it is outside. The reason for this is the poor thermal performance of houses in Australia. Our homes must be quickly improved to fight against climate change, fight against energy poverty and improve our daily lives.

Minimum building standards for energy and comfort in Australian homes lag far behind many regions. Fifty years ago, it was the oil shocks of the 1970s that sparked the creation of energy standards for buildings in Europe and North America, and a widespread shift to double glazing, increased insulation and concern for efficiency. energy. In Australia, it was not until the 1990s that minimum insulation requirements appeared. It wasn’t until 2003 that the Australian Building Code set energy efficiency standards for homes across the country.

The performance of our homes is governed by the National Home Energy Rating System (NatHERS for short). Ratings range from 0 stars, for a home that would provide no weather protection, to 10 stars, where virtually no artificial heating or cooling is needed year-round. The current minimum performance for new homes is 6 stars, which has been in place since 2011. However, the average Australian home is only 1.8 stars. It is perhaps closer to a tent than a modern eco-house.

Australian housing then leaves much to be desired in terms of comfort and energy. Single glazing is still typical, whereas 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 may have an “airtightness” of more than 30 changes per hour – that is to say that all the air they contain will escape 30 times per hour at 50 pascals of pressure. In newer homes it is closer to 10 to 15 air changes. In comparison a high performance “Passivhaus” benefits from 0.6 or less air changes per hour. For many of us, we pay thousands of dollars a year to heat our homes, only to have that heat escape directly through the cracks in the walls.

What is the impact of this? Exorbitant bills for beginners. Estimates from 2015 suggest about 28% of Australian households suffer from some form of energy poverty – i.e. they struggle to pay their energy bills or they limit their energy consumption to the detriment of their health to stay affordable. Although soaring energy prices are driving this, leaky uninsulated homes can amplify the effects. Take a 180 square meter house in Canberra. If this received a 2-star NatHERS rating, it would have to 27,349 kWh of electricity. If we assume $0.20/kWh, the cost would be $5,470 per year. A 6-star home would require 8,249 kWh and cost $1,650, while a 10-star home would only need 100 kWh, which would only cost $20 per year.

The most vulnerable feel the effects most acutely. Research by UNSW found indoor temperatures in social housing as low as 5°C in winter and as high as 39.8°C in summer. The health impacts of this go beyond discomfort, with cold homes linked to increased blood pressure, asthma, poor mental health, respiratory and cardiovascular disease.

There are two solutions to this crisis. First, we need to significantly strengthen our building regulations. Why is this important? We know that more three-quarters of new homes are built to minimum performance requirements – few go beyond that. The good news is that Australian regulations will increase the minimum performance from 6 stars to 7 stars from September. Although this is a start, we will always be behind the EU, where all new buildings must meet almost zero energy performance – these are buildings that consume very little energy.

Arguably, upgrading our new homes is the easy part. The second solution is that we must radically modernize our existing buildings.

There are some DIY options – insulating the attic, sealing gaps around windows, etc. But for meaningful energy savings, we need to undertake “deep retrofits” – that is, the systematic upgrading of walls, roof, floor and windows while simultaneously installing heating and cooling systems. cooling. This may require extensive work and subsequent expense. The recent renovation of the Little Loft House in Canberra increased energy efficiency from 3.8 stars to 7.7 stars, at a cost of $400,000.

Achieving this on a national scale would require significant government support, focusing first on the most vulnerable – social housing, people with disabilities, the elderly. Perhaps we can look to Italy, where the recent 110% superbonus system allows homeowners to benefit from a tax credit of up to 110% of the cost of renovating their home.

There’s no place like home, or so the saying goes. But if that house is cold, moldy, expensive to heat, and unsanitary, it can also be an incredible source of stress, discomfort, and cost. We have the opportunity to improve this by tightening our building regulations and extensively renovating existing homes. We’ve been behind much of the world for far too long.

Philip Oldfield is director of the UNSW School of the Built Environment and a researcher in sustainable and low-carbon architecture

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