Building Design
Footings
Our homes will be pole homes, with steel posts set in concrete footings. This is done for two reasons - to reduce usage of concrete as much as possible, and also to induce passive cooling via air flows beneath the floor.
Cement production is one of the world's largest sources of carbon emissions, so we endeavour to reduce usage of cement and concrete as much as possible. However, there are few suitable and cost-effective alternatives for footings.
Steel-frame
GSH will use the steel-frame construction system designed by Lysaght, including their Quika-Floor, Supraframe and Supratruss systems. These comply with all Australian Standards, have been appraised by the CSIRO, and have received Certificates of National Accreditation as a building system.
Using this system saves an enormous amount of time, as well as the expense of engineering certification.
Cladding
Exterior wall and roof cladding will probably be Colorbond steel from Lysaght. Aside from the environmental benefits of steel, there are a range of profiles and colours to choose from, and the effect is modern and attractive.
People are often concerned that using steel cladding will mean that the house will heat up excessively during summer. However, with an air gap between the external and internal cladding, very little heat is transferred to the inside of the house. This can be mitigated by using insulation between the external and internal cladding, and reduced even further (especially on the roof) by using a light colour.
For internal cladding and floors, we may use an environmentally-friendly product such as Enviro Board. This is an area of current research.
Energy Production
Each home will produce about half of its energy requirements from solar power, and about half from wind. If located in an ecovillage or green development, then larger wind turbines will be used to provide the wind component for the community. However, on a stand-alone home, smaller wind turbines will be fixed to the roof.
There are two reasons for using both solar and wind. For one thing, they tend to work well together, since wind speeds are often highest when the sun is not shining, i.e. at night time and during storms or cloudy weather. With only solar power, energy can only be produced for half of each day, and only on sunny days. Using both together means energy is being produced most of the time.
Wind turbines are also considerably cheaper per kilowatt than solar panels.
Wherever possible, the homes will be connected to the main grid via an inverter, which means when the house is producing more energy than it needs, electricity is returned to the grid. When it is not producing enough, energy is drawn from the grid. The balance of these transactions could mean a small electricity bill, or it could mean a payment from the electricity provider. A grid-connected system eliminates the need for batteries, which are expensive, consume space and are hard to recycle.
Energy Efficiency
The homes will be designed in accordance with new government energy efficiency guidelines. Incorporating passive heating and cooling design principles will reduce the costs of temperature control, which typically form a large fraction of a home's electricity expenses.
Insulation made from sustainable materials will also be used to reduce heating and cooling costs.
The homes will come with energy efficient lighting, and possible also devices to ensure that items such as televisions, DVD players and computer screens are completely turned off when not in use. Another system under consideration will automatically turn lights off when there's no-one in a room.
Rainwater Harvesting
Since we are building new homes, we have the luxury of locating water tanks under the house. These will be larger-than-usual tanks to insure against the possibility that drought conditions may worsen during climate shift. Positioning water tanks under the house saves space, and also makes it easier to connect downpipes from all sides of the house to the tanks, thus utilising the entire roof area for rain harvesting.
Tanks will most likely be polyethylene, which is more environmentally-friendly than cement. Poly tanks are long-lasting, and provide better value in terms of dollars per litre of water storage than other options.
Gutter mesh, such as steel, fire-proof Blue Mountain Mesh, will be utilised to ensure that leaves and debris do not clog the gutters, and rain heads will be fitted to downpipes to deflect leaves and other debris away from the flow of water. Water will be filtered on its way into and out of the tanks.
Our water tanks may be connected to the town water supply to ensure a minimum water level is maintained. We may also incorporate a device such as Rain Alert to monitor water levels.
See Water Sub-system for more detail.
Water Recycling
Each home will have a grey water recycler (e.g. an Aqua Reviva) built-in, which will recycle water to a level where it can be re-used in the washing machine or on the garden. Incoporating a system like this greatly reduces a household's water consumption. A second tank is used to store recycled grey water.
There are several systems currently under development to recycle grey water to potable (drinkable) levels. Once these are available and cost-effective they will be incorporated into our homes to further improve water efficiency.
Dry Composting Toilet
To save a large amount of water (flushing toilets accounts for about one third of a regular household's water usage) while also producing a high quality fertiliser for your permaculture garden, each home will include a dry composting toilet such as a Rota-Loo.
Energy-Efficient Hot Water System
A heat pump hot water system such as the one by Quantum will be used, located under the house in the same space as the water tanks and dry toilet. These are even more energy efficient than solar hot water systems, and can produce hot water even if ambient temperatures drop as low as -15°C.
Cold Water System
This is a luxury item! As most Queenslanders know, tap water can become uncomfortably hot during summer months. Therefore we will offer an optional water cooler to be installed under the kitchen sink alongside the water filter.
Appliances
We will provide the option to include an energy-efficient refrigerator and/or a water-efficient washing machine with each home.
This page is a work in progress. More will be added as research progresses.
Proceed to Water Sub-system.