Heatwaves, blackouts and the future of SA homes
South Australians certainly know what a hot summer feels like. But there's a big difference between a warm day and several days of extreme heat, particularly when overnight temperatures remain high and the house never really gets a chance to cool down.
Add the possibility of a power interruption at exactly the time everyone wants their air conditioner running, and the way we think about our homes starts to change.
Increasingly, a comfortable home isn't simply one with good air conditioning. It's one that's designed to stay comfortable for longer - even when the conditions outside aren't.
So, what makes a home more resilient to heat?
Start by keeping the heat outside in summer
It sounds obvious, but one of the most effective ways to keep a house cool is to stop it becoming hot in the first place. Western sun pouring through an unshaded window can quickly heat a room. Once that heat is inside, the air conditioner has to work much harder to remove it.
External blinds, awnings, verandas, appropriately positioned trees and other forms of shading can make a significant difference, particularly on north and west-facing parts of a home.
Good design considers where the sun will be throughout the year - welcoming it when it's useful in winter and keeping it out when it's not in summer.
Insulation isn't just about winter
Insulation is sometimes thought of as something that keeps a house warm. In reality, it works both ways.
Well-insulated roof, ceilings and walls slow the transfer of heat into the home during summer and help retain warmth during winter. In an older home, it's worth establishing what insulation is actually present and whether it remains effective.
It's not likely to be the most glamorous renovation you'll ever undertake, but it may be one you notice every day for all the right reasons.
Let the house breathe - at the right time
Opening every window on a 42-degree afternoon isn't going to do much for your comfort. But when temperatures fall in the evening, good cross-ventilation can help remove heat that has built up during the day and bring cooler air through the house.
Window placement, secure openings and the ability to create airflow from one side of a home to another can all help.
Ceiling sweep fans are useful too. They use much less electricity than air conditioning and can improve how comfortable a room feels without necessarily lowering its actual temperature.
The trick is knowing when to seal the house against the heat and when to open it up. This is called passive thermal control.
What happens when the power goes off?
This is where home resilience becomes particularly interesting. A house that relies entirely on mechanical cooling can become uncomfortable surprisingly quickly during a blackout if it has poor insulation, large areas of unshaded glass and little natural ventilation.
A better-performing home buys you time.
Shading, insulation, draught control and thoughtful orientation don't stop working when the electricity does. That doesn't mean designing a house as though air conditioning doesn't exist. It means making sure air conditioning isn't doing all the work.
Solar and batteries change the conversation
South Australians have enthusiastically embraced rooftop solar, and home battery storage adds another dimension.
A battery can store electricity for use when solar generation falls or grid electricity is expensive. Depending on how a system is designed and configured, battery storage may also be able to provide backup power during an outage.
But that's an important ‘depending’.
Simply having a battery doesn't necessarily mean every appliance in the house will continue operating normally during a blackout. Homeowners considering backup capability should get expert advice and discuss what circuits and appliances they want supported, how much battery capacity is available and how the system will operate if grid power is lost.
New homes are already being asked to perform better
Building standards are moving in this direction too.
South Australia's modern homes provisions commenced in October 2024 and increased the thermal performance requirement for most new Class 1 homes to a 7-star equivalent energy rating, alongside whole-of-home energy requirements. Some specified developments and allotments are subject to transitional concessions.
The important point isn't simply the number of stars. Orientation, glazing, insulation, sealing, ventilation and building materials all contribute to how a home performs. A home that needs less energy to remain comfortable is better placed to cope with both extreme temperatures and interruptions to energy supply.
Older homes shouldn't be written off
Of course, most South Australians aren't living in newly constructed 7-star homes - and improving resilience doesn't necessarily require knocking the house down and starting again.
An existing property might benefit from better ceiling insulation, external shading, draught sealing, improved window coverings, ceiling fans or more effective zoning of air conditioning.
Larger renovations provide an opportunity to think more fundamentally about glazing, ventilation, orientation and how different parts of the house respond to summer sun.
Deciduous trees can play an important role. They shade the northern side of a home during summer, but let the sunshine through in the winter when they lose their leaves.
Often, it's a combination of relatively ordinary measures that makes the biggest difference.
Think about resilience before the next heatwave
It's easy to think about cooling when it's 40 degrees outside, but the better time is before summer arrives.
A building consultant can help identify aspects of an existing home that may affect its thermal performance, including insulation, ventilation, building condition and maintenance issues. For homeowners planning a renovation or extension, independent advice can also help ensure today's design decisions don't create tomorrow's problems.
