A Blue Mountains house that maintains a steady 20-25 degrees without heating or cooling. Sounds too good to be true, doesn't it.
Except it isn't.
Joe and Merylese Mercieca have built the first certified passive house to flame zone regulations in the Blue Mountains.
They say there are only 17 other certified passive houses in Australia, certified through the International Passive House Association.
A passive house is built to be highly energy efficient.
Mr Mercieca said it cost "less than a take-away cup of coffee a day" to run the house - a mere 13.3 kW. With the addition of solar panels, the house's carbon footprint is zero.
The Winmalee owners of Blue Eco Homes, took a year to build the four-bedroom weatherboard display home in Faulconbridge.
With triple glazing on the windows, good insulation and an airtight building, this ensures a comfortable internal temperature in the home, with minimal reliance on heating and cooling.
A ventilation system controls how much air comes into the house, also helping to maintain the temperature. Mr Mercieca said there were .39 air changes an hour, compared to 15 per hour in a typical house.
"A ventilation system brings filtered clean air throughout the entire house so there's no Co2 build up inside - perfect for people with respiratory issues or those seeking a healthier lifestyle," he said.
"Passive houses offer an entirely new way of building a home. It moves beyond minimum building requirements and looks to the future. A future where we rise to the challenge of building smarter, longer lasting homes that are healthy, energy efficient and incredibly comfortable."
Mr Mercieca was raised in a family where sustainability was important. His dad was always collecting rainwater and laundry water to be reused throughout the house.
It's a practice that's also been adopted in the family's Winmalee home, built 10 years ago, which is fully solar-powered and all water is recycled.
Despite being told at the time "they were crazy", the couple persisted, and have continued their journey to build an even more sustainable home.
"I needed another challenge," Mr Mercieca said. "We just pushed it and saw what we could do."
That involved extensive research on passive homes, which have been part of the European landscape for 30 years.
Building a passive house to flame zone regulations added an additional challenge, as traditional flame zone houses are locked up tightly, so if a bushfire hits, embers can't penetrate the home.
"You have to stop the embers getting in, but you still need the house to breathe so there's no moisture in the walls," Mr Mercieca said.
The couple say the cost to build a passive home is 15 per cent dearer than a standard build, but this extra initial outlay can be recouped through the low running costs.
The home will be open to the public via bookings, from "Sustainable House Day" on September 15.
