In 2012, our director Josh Byrne wanted to demonstrate that a house could be built using typical Perth construction methods and on a typical budget, but use much less energy and water, and produce far less carbon emissions than a typical Perth house. This means consuming, in comparison, just 10% of the energy, 20% of the mains-supplied water, and yet producing only 10% of the carbon emissions.

Many said that this was possible but very few had actually done it. Would the house perform as expected? Would the budget blow out? And, would the family love it?

To ensure that the results could be tested and published to demonstrate better building, Josh had a set of goals:

The house would be a 10-star rated energy-efficient home, constructed at a similar price and timeframe as a regular build, using standard materials and methods familiar to local builders. It would meet indoor air quality benchmarks and Universal Access design principles, be a net energy exporter on an annual basis, and collect and recycle water onsite. And, there would be gardens to provide food, habitat, shade and natural play areas.

Design for place

Before building the house, Josh made sure he understood the topography, climate and general context of the area. Perth has cool winters with hot, dry summers, and moderate rainfall concentrated into heavy bursts during winter or spring. With that in mind, Josh chose a block of land with an east-west axis, allowing the house to have a long exposure to the north to catch plenty of northern light and warmth during the winter.

The next step was to make the building suited for the different seasons. Good insulation and building sealing keeps the heat in, or out, depending on the season.

Josh installed a light-coloured roof to reflect the hot sun, while windows were positioned to let in plenty of winter sunlight, but can be shaded in the summer. They also allow good cross-ventilation to take advantage of Perth’s coastal location and the cooling afternoon sea breezes.

He planted a garden to create a cooler outdoor micro-climate in the summer, which also provides seasonal shading. A hydro-zoned irrigation system gives the plants just what they need, reducing waste. Rain is collected from the roof, treated and used to supply the house and the garden.

The roof also features solar panels, producing more energy in total than the house consumes over a year – giving electricity back to the grid! There is also a solar water heater, supported by a gas booster, such that most of the house’s hot water is heated by the sun.

Sensors to show: does it work?

A key element not found in a typical Australian home is the extensive monitoring system of more than 100 sensors installed in Josh’s house.

Energy, water, temperature, air quality and weather sensors are logged constantly to supply data to the family, the various researchers following the project, as well as to the public, open source, through the project website.

Josh and his family use the data on a daily basis to watch for any unexpectedly high consumption. It’s always tempting for a keen gardener to be a bit generous with watering his plants, but the hard data tells Josh when to stop. Lighting is a large part of the electricity load, despite efficient LED lamps, so Josh is looking at lower power versions.

After the first year of operation, the result is clear: it is possible to build a standard house within budget, with a 10-star energy rating, and even produce more energy than consumed.

With zero heating or cooling, Josh’s house manages to have an average temperature of 25°C. Outdoor temperature, in contrast, varies from under 5°C to more than 40°C.

The house has 72% less carbon emissions than the Perth average, going beyond carbon-neutral, offsetting more carbon than is used. There are plans to go further, and rely less on the energy grid.

Most importantly, the ultimate test: Does the family love it? Yes, they do!