Australia is getting hotter. Climate change is driving more frequent and prolonged extreme heatwaves and our homes are struggling to keep up. Alarmingly, many Australian houses – especially older ones – weren’t designed for these harsh conditions.
During a heatwave, large parts of the country’s interior can soar above 40°C. That’s not only uncomfortable but also dangerous, as extreme heat puts residents at serious health risk.
Heatwaves have caused more deaths in Australia than any natural disaster combined.
That’s where smart materials come in. They can significantly change some of their properties in a controlled manner in response to external stimuli, such as temperature. And they are being incorporated into materials such as bricks and roof cladding to make homes more resistant to heat fluctuations.
Air-conditioning can’t save us
The default fix? Turn on the air conditioner. But cooling our homes with machines comes at a cost. Our growing reliance on air conditioning creates a dangerous feedback loop: more heat leads to more energy use, which ultimately drives up carbon dioxide emissions if no solar power is available.
You might be surprised to learn that buildings are responsible for around 40% of global energy use and nearly one-third of carbon dioxide emissions. In Australia, up to 50% of household energy is consumed for heating and cooling depending on the climate zone – and demand peaks during heatwaves.
To reach net-zero emissions by 2050, we need more than just efficient appliances and rooftop solar. We need to rethink how homes interact with heat – and that’s where smart materials can make a real difference. Instead of simply blasting air-conditioning, we can build homes that actively respond to their environment.
An office building covered in air conditioners in Brazil. Image: Bran Sodre/Pexels
Homes that regulate themselves?
Imagine a material that passively absorbs excess heat during the day and releases it back into the home when temperatures drop at night, with no switches, no electricity and no noise. That’s the magic of phase change materials, a type of smart material. They are made from materials such as waxes, salts, fatty acids and plant-based oils, and come in the form of thin panels, microcapsules, and liquid-filled pouches.
These materials absorb heat as they melt and release it again when they solidify, acting like a thermal battery embedded in your roof tiles or walls. A thermal battery stores energy in the form of heat instead of electricity. This means your home can “charge” with heat when it’s warm and “discharge” that heat when it’s cool.
In summer, phase change materials absorb indoor heat during the day, which keeps living spaces cooler. At night, as outdoor temperatures drop, they release that stored heat. In winter, it’s the opposite.
Phase change materials can offer even greater thermal mass than traditional materials like brick, stone or concrete. And studies show they can reduce average building energy use by around 37% across various Australian cities.
But they do have a limitation under extreme or prolonged heat. If overnight temperatures remain high – as often happens during multi-day heatwaves – the material may not cool down enough to solidify. Once fully melted, it can no longer absorb heat, making it temporarily ineffective.
Reflective coatings
Like slipping on sunglasses on a sunny day, reflective coatings shield homes from the sun’s harsh rays. When applied to rooftops, they can lower indoor temperatures by up to 4°C. This means less reliance on air conditioning and lower energy bills – a simple, cost-effective way to beat the heat.
But there’s a catch: what works brilliantly in summer can backfire in winter. These reflective surfaces also bounce away the warmth you want during colder months. And instead of absorbing heat, your home gets chillier.
To build homes for a warming world, we need solutions for all seasons – smart materials that respond to their environment by blocking heat when it’s hot, and absorbing it when it’s cold.
The future is adaptive
Our homes need layered strategies. Imagine a roof that not only reflects intense summer heat but also works with phase change materials to absorb and regulate indoor temperatures year round.
In a recent study, led by this article’s lead author, Md Jaynul Abden, reflective roof coatings combined with phase change materials embedded in roof tiles and gypsum board were found to significantly improve home performance during simulated Australian heatwaves.
The results were striking: indoor temperatures dropped by 7.9–9.7 °C across cities, and energy savings reached up to 80.6%. Most importantly, indoor environments remained significantly more comfortable. This is a critical benefit during heatwaves, especially for vulnerable communities without air-conditioning.
By carefully balancing the reflection and absorption of materials, we can ensure they perform optimally. These solutions aren’t mainstream yet, but as heatwaves intensify and the demand for energy efficiency grows, adaptive roofing systems are likely to become common in new builds and retrofits within the next decade.
We had a thoroughly enjoyable final Skill Share Saturday for the year yesterday with Qigong, Fashion Upcycling, Seed Saving and Bushcare! We shared seeds from local gardens and harvested carrots, as well as Mizuna, Broad Bean, Daikon and Land Cress seeds from the Planetary Health garden. We then packaged up (and shared) our first Upper Mountains Seed Savers packs for our fledgling Seed Bank. In Bushcare it`s very exciting to see whole new areas of the Planetary Health Precinct open up as we remove invasive weeds. It`s been a year of great progress as we`ve restored habitat for wildlife and given local native plants the opportunity to flourish and re-establish on the site.
Join the Planetary Health Centre this Sat 6 Dec for the last Skill Share Saturday of the year: Qigong at 9am, Seed Saving & Gardening Group at 10am, and Bushcare at 1.30pm. One perfect day with great company, great coffee and food, and great steps for living a healthy balanced life, while also contributing to the health of our planet for present and future generations. All ages welcome!
Registration links in profile and below.
Register for Qigong here: https://bit.ly/48wlHjD Register for Seed Saving & Gardening here: https://bit.ly/4prcRe7 Register for Bushcare here: https://bit.ly/4oAFDrz
We have a rare opportunity to learn about the newest and best possible ways to support family and community members struggling with mental health issues, at a free talk and afternoon tea provided by Upper Blue Mountains Sunrise Rotary at the Planetary Health Centre at 2pm this Saturday 29 Nov. Hear from Peter Joseph AM, Chair of the Black Dog Institute, and Professor Helen Christensen AO, Fellow of the Australian Academy of Science and former Executive Director and Chief Scientist at the Black Dog Institute. They`ll be in conversation with journalist Emma Rossi. Dr Christensen is a pioneer in using the internet to reach young people struggling with depression. Her digital mental health interventions are used by millions globally, delivering evidence-based therapy for depression, anxiety, and suicide prevention. Her research uses data from smartphones and wearables – like movement, screen use, and sleep – to detect early signs of mental health issues. Bookings essential here (link in profile): https://bit.ly/4oOnYxz
This Saturday Sherlie McMillan from Rotarians 4 Planetary Health will be running a workshop on How to use a sewing machine from 9am at the Planetary Health Centre in Katoomba. Learn how to set up a machine, service it, troubleshoot when it`s not sewing correctly, and learn some basic sewing skills.
Bookings essential here (link in profile): https://events.humanitix.com/how-to-use-your-sewing-machine
NB. This class is a prerequisite for our very popular Fashion Upcycling classes held once a month.
We`re thrilled to announce that Professor Helen Christensen, a pioneer in using the internet to reach young people struggling with depression, will be joining the conversation with Peter Joseph AM from the Black Dog Institute and journalist Emma Rossi at the Planetary Health Centre at 2pm this Saturday 29 November. Helen was the Executive Director and Chief Scientist for the Black Dog Institute for 10 years and has now been elected a Fellow of the Australian Academy of Science. Her digital mental health interventions are used by millions globally, delivering evidence-based therapy for depression, anxiety, and suicide prevention. Her research uses data from smartphones and wearables – like movement, screen use, and sleep – to detect early signs of mental health issues. This free event is being co-hosted by Upper Blue Mountains Sunrise Rotary and the Blue Mountains Planetary Health Initiative. Afternoon tea will be provided. Bookings essential here (link in profile): https://bit.ly/4oOnYxz
Human composting is increasingly being legalised around the world. Read about it in Katoomba Area Local News here (link in profile): https://www.katoombalocalnews.com/legalising-human-composting/
If you’d like to see this option available in NSW you can now sign a live petition to the NSW Parliament here (link in profile): https://bit.ly/43QIHbz
Thanks to everyone who contributed to deliver a fantastic Disaster Risk Awareness Expo and Family Day yesterday. @mark_greenhill_mayor opened the event at which we celebrated the 13th birthday of Betty the Asbestos Education House; @firecoat_au demonstrated and launched its range of fire retardant products that can help protect homes, gardens and even electricity poles; the Bushfire Retrofit Toolkit was launched; Santa arrived and delighted young and old; and @plantinspired99 and Action for Animals fed us all with a delicious plant-based sausage sizzle. The day was filled with talks, workshops, stalls and the sharing of a huge amount of expertise to keep us, and the other species we share our planet with, safe and healthy! @southkatoomba.rfb @nswses @fireandrescuensw @nswrfs @redcrossleura @redcrossau @shelter.building.design @firehalo.au @asbestosawareness @amelie_ecology @bbagsbluemtns @wireswildliferescue @handsheartfeet
Our marquee is up and we`re excited about our Expo and Family Day tomorrow (Sat 22 Nov). There`s something for everyone from a free sausage sizzle, plants from Santa and drumming and pollinator workshops, to sessions on keeping you and our community safe from extreme weather events and hazardous substances like mould and asbestos. Learn how intumescent paints can slow the spread of fire and pick up a sample pot; check out all our emergency service organisations; learn how to dispose of hazardous materials; paint a native orchid, make some seed balls or sew a boomerang bag to give as plastic-free Christmas presents this year; enjoy coffee and locally made sweets; and get tips on how to retrofit your home safely and beautifully to be prepared for future extreme weather events. View the full program and register here (link in profile): https://bit.ly/4nFrY1J
There are so many new and innovative ways of doing things, like the new cooking techniques being explored by Michael from Good Fat Pastry, and the new fire protection methods being launched at the Planetary Health Centre`s Expo and Family Day on Sat 22 Nov. Check out Michael’s recent presentation at the Food Security Fair in our video here: https://bit.ly/4pnXbIg (link in profile) and come along to taste his delicious carrot cake and pastries at the Expo on Saturday. Check out the program and register to attend here (link in profile): https://bit.ly/4nFrY1J
In 2006 Peter Joseph’s son Michael suicided after a 14-year episodic battle with mental illness. Peter is now the Chair of the Black Dog Institute which is working to achieve better outcomes for all those struggling with mental health issues. Journalist Emma Rossi will engage Peter in an intimate and moving conversation about a life of purpose and mental health advocacy. As a Rotary scholar Peter will also reflect on how Rotary helped shape his values and sense of purpose as a young man - and how those early lessons continue to guide his work today. This free event is being hosted by the Upper Blue Mountains Sunrise Rotary Club and the Blue Mountains Planetary Health Initiative on Saturday 29 November from 2-4pm at the Planetary Health Centre at 33-39 Acacia St Katoomba. Afternoon tea will be provided. Bookings essential here (link in profile): https://bit.ly/4oOnYxz
Learn about intumescent fire retardant paint and a range of other strategies to prepare for extreme weather events, and to manage hazardous materials, at the upcoming Expo and Family Day at the Planetary Health Centre on Sat 22 Nov. You can register to attend here (link in profile): https://bit.ly/4nFrY1J We checked out how intumescent paint works in this video.
When temperatures reach a certain point the intumescent paint begins to swell and expand, often up to 50 times its original thickness. It forms a thick, carbonaceous "char" that acts as an insulating barrier. This layer slows the rate at which heat reaches the structural elements and buys valuable time for people to safely exit a building during a fire. It makes the structure safer for firefighters and rescue teams. #intumescentpaint #fireretardant #bushfire @firecoat_au...
Mould, lead paint, asbestos, silica dust from engineered stone bench tops and a wide range of chemicals, are amongst some of the many hazardous substances entering our environment and negatively impacting our health. Asbestos is found in over 3000 products including textured paints, moulded garden pots, brake pads and clutch linings in older cars, floor and ceiling tiles, lino, fibro, roofing, pipes and gutters, hot water systems, backing for switchboards and insulation boards in air-conditioning ducts, insulation, sealants, fillers, caulking and adhesives, gaskets for industrial and lab equipment and more. We’ll have information to take away and Blue Mountains City Council and the Asbestos and Hazardous Materials Consultants Association (AHCA) will be running free workshops on how to identify and manage these hazardous substances at the Planetary Health Centre`s Disaster Risk Awareness Expo in Katoomba on Sat 22 Nov. Find out more and register to attend here (link in profile): https://bit.ly/4nFrY1J
There is a little bit of magic happening on Wednesdays at the Planetary Health Centre as young volunteers from Kindlehill School, and Council staff, work together to create a demonstration site for the wider community. This hands-on program is inspiring all involved, including teacher Sarah Daniel.
