It also has a 25,000-litre concrete rainwater tank built under the garage with plumbing that goes throughout the house. It is used for washing, drinking and in the toilets.  Because of this they do not need to be on city water.  The water tank is built on a concrete slab and also acts to balance the temperature inside the house.
There is also a concrete floor, overlaid with bamboo slats, that absorbs and retains the heat in winter. The internal walls are brick and come with sarking and concertina insulation.
Solar panels were placed to the north of the block, with a photovoltaic bank linked to a T3 hybrid energy system. This was they generate about 20 per cent of their own power.
It goes into the grid during the day and is drawn on at night.

Smaller details include:-

•  All the internal doors are topped with small awning windows that are opened in summer to aid air flow and closed in winter to trap heat.
• Ninety-five per cent of the lights are compact fluorescent, and the central gallery and stairwell are surrounded by windows.
•  There is a 200 square metre garden (with almost all native species) that is irrigated with a grey-water system that reuses water from showers and hand basins. The garden paths are made from recycled concrete and bricks from Kimbriki Tip at Terry Hills.
 

This house along with others in the Manly area can be viewed on Sustainable House Day. For further details contact mec@manly.nsw.gov.au.