Bundanoon local Glenn Robinson built a house that produces more energy than it uses for $162,000. The Net Zero Cottage in the New South Wales Southern Highlands is a two bedroom, one bathroom standalone house that will be open as part of Sustainable House Day on September 11. Glenn says you can have energy-efficiency, low building costs and good aesthetics all in one. "It's so simple, the principles have been around for years but the building codes haven't kept up on what's going on in the rest