A White Gum Valley couple have built a “thermal battery” home that slashes their power and water bills in half.
Martin Anda says their sustainable home ‘Djildjit’ is naturally warmer in winter and cooler in summer.
The passive solar apartment is connected to an identical ‘twin’, with both constructed from rammed earth.
Mr Anda and his wife bought the plot of land along with friends who live in the other apartment.
They share a permaculture garden and an edible verge garden that doesn’t use any scheme water.
Mr Anda says building a sustainable house was challenging – the majority of builders couldn’t build the eco-property he wanted and there were some higher up-front costs.
“I had to pay extra for some sustainability features like solar PV, greywater, rainwater and so on, but after three years living in the house I am saving more than 50 per cent in power and water bills,” he says.
“I also believe I have a better quality of life in the house than the average Perth house owner because I have a naturally day-lit house, warmer in winter, cooler in summer, and a beautiful garden with fruit and vegetables using no scheme water.”
Mr Anda says the house is like a “thermal battery”.
“Walls and floors are heavy thermal mass of rammed earth and concrete,” he says.
“The mass floors have hydronic tubing installed, which circulate hot water in winter and cool water in summer from a 3-in-1 heat pump,” he says.
“The heat pump we only run during the day with electricity generated from the solar PV rooftop power system by means of a webapp programmable controller.
“So instead of exporting surplus solar electricity to the grid during the day when we are not home, it goes to the heat pump and the house is warm or cool when we get home into the evening with free energy.”
They also made the most of the modest 274sqm available with half the garage roof devoted to a roof garden planted with local flora and the other half a covered terrace with barbecue and outdoor sink.
“A community bore scheme reticulates groundwater to all homes at White Gum Valley for sub-surface irrigation of the apartments’ extensive edible garden,” he says.
“All four occupants of the apartments compost food scraps and other organic waste in two alternating compost bins on site, returning the worm-rich product to the garden.
“We also have the Subpod, a worm farm in a raised bed on the verge, by Freo inventor Andrew Hayime De Vries.”
Mr Anda says the twin one-bedroom apartments are proof that urban density can coexist with sustainability. He wants more Aussie builders and developers to follow suit.
“Our housing produces 40 per cent of the world’s greenhouse gases in both construction and operation over their life,” Mr Anda says.
“Perth housing, while awfully energy inefficient is also horribly water inefficient, so I wanted to address that as well as sustainable gardening with permaculture.
“I enjoy living a more eco- friendly life.”
The Anda’s sustainable house is being featured as part of Sustainable House Day on October 17, with lots of lead-up events in store.
For more details go to sustainablehouseday.com