Sustainable house details


Climate Zone: Warm Temperate

Architect/Builder: Gisela and Walter Duber

Unique Sustainable Elements featured in this home

Water Harvesting Systems

We are not mains connected and four tanks totalling 63,000 litres supply water for the house and garden. Two tanks collect rainwater from the house and the shed and water is periodically pumped up the hill to two concrete storage tanks and then gravity fed back separately to house and garden. This minimises electricity use for pumping and makes water available during power cuts. An effective but simple first flush diverter is fitted which completely drains the pipes in dry periods.

All waste water (grey and black) is reused by being pumped (sub surface) onto the orchard after being treated by a horizontal reed bed treatment system.

External Walls

Mud brick walls with bricks made by Bellingen Bricks; size 250mm x 150mm x 400mm. The lintels are red ironbark recycled from old railway bridge timbers.

Internal Walls

The core internal walls are mud brick resulting in about 20 tons of thermal mass inside the house. The remainder are Cypress Pine stud walls.


Light green colorbond roof at 22 degree pitch. R3.5 insulation is fitted in the ceiling cavity and the main room cathedral ceiling was double insulated.

The ridge beam is recycled hundred year old timber from the old Wingham abattoir, and the supporting post is the top of a tallowwood left behind by loggers.


Suspended tallowwood floor with tiles in the wet areas.

Window Treatments

There are extensive windows especially to the north (the views are special) where 900mm eves allow passive solar heating in winter, while blocking the summer sun. The cliffs to the east and west reduce the morning and afternoon heat, while the veranda on the west side provides afternoon shade. We investigated thermal coatings on the windows but rejected them as there was some concern about them scratching rather easily. The windows and doors are made by Customline Joinery in Wauchope who are highly recommended.

Solar or Wind Power Generation

The 2.6Kw BP and SMA grid connected photovoltaic system was sized to cover our electricity usage over the year but has not generated quite as much as we hoped, probably because the weather has been very wet over its 21 month life. It supplies an average of 7KWHr per day, which covers our current needs.

Heating & Cooling

Heating is by a wood burning stove using dead trees collected from the property.A heat transfer system pumps air from above the stove in the living room though to three outlets in the bedrooms and study using a 250mm inline fan, and keeps the bedrooms about 4 degrees warmer than they would be otherwise during winter.

The house was designed to channel the through breeze using large louvre windows. The main room has a high cathedral ceiling with a gable window which allows us to vent hot air quickly on summer evenings. The living space normally stays under 26° unless we get consecutive days of above 40° temperature coupled with hot evening temperatures. We have recently added a small A/C to take the edge off these conditions which are becoming more common.

Water Heating

A Beasley solar hot water system is installed with a tank in the ceiling space and two panels on the roof. The tank is unpressurized and runs two thermosiphon loops, one from the panels and one from the wood burning stove via a heat exchanger in the first segment of the flue. Hot water runs through a coil of pipe in the tank and so is at the same pressure as the cold water. An electric boost is fitted but virtually never used.


Most of the lights are commercial compact fluorescents which have the ballast in the fitting, but we have not yet found a suitable efficient solution for kitchen task lighting, as we find the LED downlights are not powerful enough.

Food scraps are fed either to the chickens or the worm farm, and our veggie patch produces most of our vegetables, especially in summer. The orchard provides all the citrus we need and stone fruit, figs pecans and macadamia nuts. We started keeping bees last spring and so far our single hive has flourished and kept us in honey.

  One Response to “Sustainable house details”

  1. [...] the +2°C target is still discussed in political and economic reports as if it hasn’t been [...]

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