Johannes Out's new house in the Dutch town of Leusden looks no different from the other red-brick homes in the neighbourhood, but there is a big difference. It produces enough energy for itself and to power his electric car, with a surplus that he sells to the public grid for Euro300 (HK$3,300) a year.
'It doesn't sound like much, but it's free,' said the 29-year-old. 'I'm happy that I don't need to be worried about high energy prices when my neighbours are complaining about them.'
Mr Out said that in the Netherlands, it was quite unusual for a house to lack a gas connection, but 'I wanted to build houses with a new system which would not rely on it. People did not believe us, so we built one and live in it to show them'.
The project has already caught the attention of the Dutch government, which has made sustainable construction a key part of its green stimulus package, under which Euro700 million is being spent over two years to make houses more energy efficient.
While sustainable construction is also an issue in Hong Kong, the city has yet to go further than beginning consultations to find ways to control building bulk. Few initiatives are already in place, other than subsidies to improve building energy efficiency.
Now Mr Out and his two partners in InnoConstruct are looking for developers to build more of the environmentally friendly houses. The prototype, which consumes one-third of the energy of a normal house, has a well-insulated thermal skin. It uses glass granules in its foundation and styrofoam bricks for walls. Solar panels and a windmill on the roof supply the energy, and a water pump system draws heat from 70 metres underground to warm the house.
Mr Out, who studied mechanical engineering, travelled to Germany, Switzerland and Scandinavia to shop for power-saving devices. 'The technology exists; it's the combination that makes it new and hi-tech,' he said.