There are simpler things to do than converting an uninsulated, close-to-collapse 1900s cottage in Sydney’s inner city into a haven for hotter times. But for its owners, KC and Kirsty Kasturi, it was worth the effort to make their home climate resilient.
“We’ve always been focused on trying to live a sustainable life as much as possible,” said KC. “We wanted to ensure that the house was designed for the future.”
This commitment comes as experts call for new homes to be built to standards that will remain safe and comfortable amid rising future temperatures. The government recently released a report warning of the risks of a warming planet if nothing is done to mitigate it. Alongside this, a new 2035 emissions target was announced, featuring funding commitments to help decarbonise the economy.
Alexander Symes, whose sustainable architecture practice was engaged by the Kasturis to help find an appropriate site and design the updates, explained that many Australian homes—including double-brick ones—can withstand isolated very hot days but would likely falter during consecutive days of high temperatures.
“The fact is that our climate is changing, and we need to make our housing stock more appropriate and adaptable to the changing climate scenario, especially within heatwaves,” he said.
The Kasturis, both engineers in their 50s, decided to move from Singapore—where they lived for 12 years—to Sydney, following their two university-age daughters. Even before their planned arrival in 2025, the couple made it their goal to buy and renovate an existing inner-Sydney house into something climate-hardy.
“So, by reusing something that’s already made, it’s reducing the impact on the environment,” said Kirsty.
The couple prioritised using fewer building materials and considered both embodied energy and operational energy as part of their home’s redesign. Embodied energy is the total amount of energy needed to produce the materials that make up a building, while operational energy refers to the energy used within the building.
They also wanted to reduce ongoing costs once the house was built. “By reducing heating and cooling needs, installing solar panels, creating a space to grow food, and collecting rainwater,” Kirsty said.
The Kasturis are not alone in this thinking. Symes noted that 80% of projects at his practice are retrofits, with only 20% being new builds.
“People are looking at how much energy it takes to heat and cool their houses. They’re seeking sensible, practical solutions to create healthy, comfortable indoor environments while being respectful of resources,” he said.
In 2022, the Kasturis purchased a double-brick Victorian home in Forest Lodge, which had a more recent addition out the back. The house had no insulation and single-pane glass throughout—the very opposite of climate-conscious design.
On the inside, it looked decent. “It looked liveable, but what the contractors told us when they started pulling the roof and everything down was that it was pretty close to collapse,” said KC.
Symes’ design for the near-airtight home included insulating the existing timber floor, removing the old tiles, and insulating the roof. The 1900s double-brick exterior was maintained, but the later addition was removed, with the bricks retained for reuse in a new structure.
“We added a new two-storey addition to the back of that cottage, made out of carbon-neutral concrete and an insulated timber frame,” Symes explained.
The home features a smart membrane that manages moisture, as well as a heat recovery ventilation system that maintains healthy indoor air quality. The existing timber-framed windows were upgraded with vacuum-insulated glass—very thin but equivalent to triple glazing.
The renovation followed the principles of the EnerPHit standard, which guides the use of much less energy to heat and cool existing buildings. “This is a slightly relaxed criterion for adapting existing buildings to the Passive House standard, which applies to new buildings,” said Symes.
After several planning iterations with the council, it took about a year for the home’s design and approvals to be completed. Construction took approximately 18 months and was carried out by Red Cedar Constructions, specialists in Passive House building.
KC admitted, “It would probably be easier and cheaper to build a new house. Recycled materials often cost more than new options, which are more readily available.”
The Kasturis moved into their renovated three-bedroom, two-bathroom home—with an additional multipurpose dwelling that includes a lift for accessibility—a few months ago. They say they love it.
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