The Bundanoon "Net Zero Cottage" designed by the couple will be open for viewing by the public on Sustainable House Day, Sunday September 14.

The house is run entirely on solar energy, and all appliances are electric.

"Even the barbecue and the lawn mower are electric," Mr Robinson said.

In the 12 months since its completion, the house has generated almost twice the amount of energy it has consumed with solar panels on the roof.

Mr Robinson said the goal for the house was to show that a sustainable house can be built easily and without excessive cost.

"It's actually cheaper and more pleasant to live in than a standard house," he said.

Even in the cold Southern Highlands winters, the air conditioning is rarely used due to the design.

"It's built like a shallow cave, facing north. It naturally stays warmer than outside by about five degrees," Mr Robinson said.

"It's comfortable, not cold and there's plenty of daylight," Mr Robinson said.

The house was built with standard materials and Mr Robinson said the idea was to keep the project simple.

"It's not expensive or complicated," he said.

Mr Robinson said the impetus for building an environmentally friendly house came from thinking about future generations.

"It's just about respecting the people to come, and appreciating the hard work of previous generations as well," he said.

The House, at 30 Hill Street, Bundanoon, will be open for guided tours between 10am and 4pm on Sunday, September 14.