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Sunbird House

3 bed, mid $400's, Edge Hill (2000)

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Behind a modest suburban facade is an innovative, naturally cool house built of local grown timbers, generating power for export to the grid and providing its own water supply.

Brief & Context

The developer of this house wanted to undertake a demonstration project to show Cairns what was possible. She deliberately chose an ordinary suburban block in Edgehill and wanted a house, that while interesting, is essentially suburban. Studio Mango were instructed to include as many sustainable technologies as possible as well as ensure careful materials selection.

Design Approach

The house was divided into a living and sleeping pavilion strung along the site facing into the prevailing south easterly breezes. A small set of steps divided the two halves and managed the small cross fall on the site. To the north side were utility areas that needed the including clothes drying, solar power and composting toilet. The cheaper and simpler sleeping half has a simple truss roof and flat ceiling while the living half has a vaulted ceiling with exposed trusses and high level light and ventilation.

Sustainability

A host of sustainability measures were incorporated:

Keep it Cool – Passive Design

  • The first step in a comfortable house and in energy efficiency – keep the house cool so air-conditioning is not needed. Air conditioning of houses is a significant and rapidly growing part of Queensland’s energy use and greenhouse gas emissions.
  • Big, insulated roofs keep the heat out and the sun off the windows and walls.
  • Additional awnings to east and west assist with lower sun angles.
  • Walls are painted a light colour to reflect heat, and have a reflective foil lining for further insulative effect.
  • The house is of ‘lightweight’ construction, being built of timber. This lack of ‘thermal mass’ means it will cool down very quickly in the early evening, unlike a masonry house.
  • Passive design principles focus on orientating the house to prevailing south-easterly winds (all bedrooms and living areas face these breezes). Cross ventilation is combined with convection currents (hot air rises) through the house bythe use of ridge vents, slatted ceilings, high level louvres and strategic window placement.
  • Outdoor living is an integral part of the Cairns lifestyle and always cooler. Outdoor areas also help shade the house.
  • Window systems such as awning and louvre windows are designed to be left open even in rainy conditions, thus ensuring constant airflow through the house. Westerly windows are glazed with tinted glass to further reduce solar heat loads.
  • Lots of natural light – houses can be quite dark in the wet season leading to increased light use
  • The vegetation of the yard area provides further shading and temperature modification.

Save Energy and Greenhouse Gas Emissions – Energy Efficiency & Production

  • Mechanical cooling is limited to ceiling fans. No air-conditioning is needed.
  • Energy efficient appliances such as dishwasher, washing machine and refrigerator (five star ratings) reduce energy use.
  • Energy efficient lighting, especially compact fluorescents can make a surprisingly large difference.
  • A covered drying area negates the need for a clothes dryer.
  • A solar hot water system with a manual boost switch only needs boosting a few times a year during the cloudy wet season.
  • Gas cooking has lower greenhouse gas emissions than electricity from coal fired power.
  • Solar panels on the roof produce all the day time energy needs. This energy is exported to the Grid during the day and drawn back at night.

Save Water – Efficiency & Production

  • All appliances are five star rated for water efficiency
  • All taps and showers are rated for water efficiency as is the dual flush toilet
  • A composting toilet as a second toilet further reduces water consumption
  • An extensive array of rainwater tanks intended to meet up to 75% of annual household water consumption
  • The site has been revegetated to restore endemic vegetation which will survive with minimal irrigation.

Materials Selection

  • Materials were selected on the basis of life cycle costing and environmental impacts including toxicity, mining and processing impacts and embodied energy
  • High embodied energy concrete and steel were limited to footings and stumps
  • There is very minimal use of PVC which has a possibly toxic life cycle with sanitary drainage in HDPE instead.
  • Copper, which is damaging to mine, has been reserved for electrical – for which there no alternative, while alternative plastics have been used for water supply.
  • The house is constructed mostly of timbers that were sustainably harvested on the Atherton tablelands, including structural framing, linings, cladding, flooring, joinery and windows
  • The roof is fully insulated with a non-fibrous insulation product

Design Team & Builder

Mango team: Su Groome, Glenn Howe, James Maude
Electrical Engineer: Simon Perkins
Structural Engineer: Chas Gianarakis
Builder: Max Bryant Constructions
Solar installation: Planetary Power
Landscape design: Siteplan

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Sunbird House Poster

Cairns Regional Council – Sustainability in House Design