Builders and architects can make a difference. Simply orienting the house on a block to gain maximum sun exposure and designing the house to store and use solar radiation can significantly increase energy efficiency and reduce harmful emissions. In the South West of Western Australia we are fortunate to have a climate makes solar/passive house an attractive energy saving alternative. The following section will highlight some major consideration for sustainable energy efficient building and provide the reader with links to further information.

A comprehensive resource which is a joint initiative of the Australian Government and the design and construction industries is available on-line at www.greenhouse.gov.au/yourhome. Much of the following has been informed by this site.

Issues relating to sustainable development and housing

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The Australian Housing and Urban Research Institute groups the sustainable development issues related to housing according to their occurrence in the life cycle of the housing. These groupings reflect the broad and complex nature of sustainability as related to building and housing. There are significant guidelines, tools and information available to assist a builder when considering or planning for sustainable construction.

Selection: includes the design of dwellings (technology, on-site construction or pre-fabrication of components); the choice and sourcing of materials (i.e. local, imported, recycled, reclaimed, from a sustainable resource, pollution, health etc.); site selection (brownfield or greenfield, habitat destruction or enhancement etc.); community design (land use, access to facilities, transport, green space).

Construction: energy use on site; site transport; noise and dust etc.

Buildings in use: includes energy use (efficient appliances, energy obtained from a renewable resource, affordability etc.); water use (recycling, water reduction measures etc.); waste disposal (recycling, reuse, composting etc.), health of tenants and their involvement in maintenance.

Refurbishment, adaptation and reuse of existing buildings: includes sourcing of materials (i.e. local, imported, recycled, reclaimed, from a sustainable resource, pollution, health etc.); off-site manufacture of components (e.g. pre-fabricated rooms that maintain existing street lines and pod bathrooms and kitchens); householder involvement.

Demolition: disposal of building materials (recycled, reused on site, landfill etc.).

Site rehabilitation: includes restoration to original condition; biodiversity.

Source: http://www.ahuri.edu.au/attachments/70137_pp_greenfield.pdf

Housing and Energy Rating Tools

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To assist the designer and builder a range of tools have been developed in Australia that enable variables in building design, construction and use to be rated according to national standards and benchmarking. The following tools and rating systems are available or in development.

NABERS - National Australian Built Environment Rating System is Australia's first comprehensive built environment rating system. Information and downloadable spreadsheets can be found here. http://www.deh.gov.au/industry/construction/nabers/index.html

· BERS - Building Energy Rating Scheme computer program is a powerful tool that is used to simulate and analyse the thermal performance of Australian houses in climates ranging from Alpine to tropical. BERS can be used to assign a star rating to a house within a particular climate type. http://www.solarlogic.com.au/Bers.htm

NatHERS - Nationwide House Energy Rating software is based on decades of CSIRO building simulation research, and it has been specifically upgraded and adapted to permit widespread use as a design/assessment tool on typical personal computers. http://www.nathers.com/

· FirstRate house energy rating software is a powerful design tool which takes the guesswork out of energy efficient design. It enables you to evaluate the energy performance of each part of a house and, by testing the effects of design changes instantly, makes designing for energy efficiency easy. First Rate is a correlation version of NatHERS. It refers to millions of NatHERS simulations to derive its rating. http://www.seav.vic.gov.au/buildings/firstrate/index.html

· BASIX - The Building Sustainability Index is a web-based planning tool designed to assess the potential performance of residential developments against a range of sustainability indices. BASIX asks for information about a proposed development, such as site location, dwelling size, floor area, landscaped area and services. BASIX compares the proposal to the average of existing housing stock. The proposal is scored according to its potential to consume less potable water or energy than the average existing dwelling. http://www.iplan.nsw.gov.au/basix/index.jsp

A page of links to other Life Cycle Analysis tools can be found at RMIT’s Greening the Buildings Life Cycle web site http://buildlca.rmit.edu.au

A comprehensive list of West Australian energy auditors and certified assessors can be found at the Western Australian Governments Sustainable Energy Development Office (SEDO) web site www1.sedo.energy.wa.gov.au and at the Housing Industry Associations (HIA) web site www.greensmart.com.au.

Other tools, downloadable spreadsheets and on-line energy use calculators can be found in various section of this document.

The next section will highlight some key areas for consideration, give a brief explanation of them and provide links to web-based information and tools.

Careful designing and planning of the building and surrounds

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The design phase should take a long term view of the house and incorporate energy saving devices that will have a positive cost-benefit over the life cycle of the home. It may be beneficial in the long term to add minor cost up front in the initial construction phase in order to gain a long term advantage. The design and building design and building

phase should also address, landscaping to minimise water use, maximise storm and waste water re-use, maximise heating/cooling properties of plants and materials, and plan for minimum waste during construction.

Incorporate solar/passive design

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“Passive systems use the fabric of the building itself to collect, store and distribute heat. The design is influenced by the local climate”

The following are features of passive design:

1. house orientation,

2. thermal mass,

3. ventilation,

4. insulation,

5. emissivity, (reducing ozone depleting emissions and greenhouse gasses)

6. window and awnings size and orientation,

7. adequate eave overhangs and shading for improving energy efficiency in the long-term,

8. natural lighting,

9. strategies to accommodate the local climate and environment

10. material selection according to thermal mass, insulation and emissivity, to provide maximum thermal benefits.

Source: adapted from http://www.newtonhouse.info/passive.htm

Maximising climatic conditions for heating and cooling

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Houses gain or lose heat in 3 basic ways:

air infiltration - passage of air through cracks and around doors or through open windows and doors. The average home loses 20-30% of heat in winter by air infiltration;

heat conduction - conduction of heat through materials of which the house is built. Controlling the temperature difference and air movement between inner and outer surfaces of walls, floors and ceilings is the best opportunity for reducing heat conduction. Heat conduction represents up to 50% or more of the total heat exchange between a home and the outside environment;

solar radiation - heat is transmitted into homes by penetration of the sun's rays. Up to 90% will be transmitted into the living area if rays are received perpendicular to a single pane. Sunlight will be increasingly reflected by the glass as the sunlight departs from the perpendicular.

Source: Powell, K (1996) Conserving energy with plants

Passive design maximises local climatic conditions. Even in a non-passive design home applying the following principles can make significant energy savings.

Correct orientation. “Good orientation increases the energy efficiency of a home, making it more comfortable to live in and cheaper to run.”

“Orientation for passive heating is about using the sun as a source of free home heating. Put simply, it involves letting winter sun in and keeping unwanted summer sun out. This can be done with relative ease on northern elevations by using shading devices to exclude high angle summer sun and admit low angle winter sun.”

Source: Good Residential Design: Good Residential Design - Your Home - Orientation

Generally speaking the house should have the living area’s facing north. North facing windows and glass doors reflect the suns heat which is absorbed by objects (thermal mass), including walls and floors, inside the building. The diagram below shows ideal orientation for different blocks.

Source: South Australian Government - How do I Build an Energy Efficient Home?

Using a thermal mass to capture and store solar radiation during the day and releasing it at night. This can be a wall or a stone floor area. Trombe walls are specifically designed for capturing, storing and releasing thermal energy.

Carefully placed windows and vents can utilise the breeze, directing either warm or cool air though the home for heating or cooling.

Fixed eves built at the right angle can shade the sun in summer and allow maximum penetration during winter.

Adequate insulation and reflective roofing finishes capturing or reflecting heat and preventing heat loss.

Note: Homes on sites that have restricted northern exposure can still make significant gains by careful design, i.e. using atriums, and roof angles to maximise energy efficiency, see this award winning energy efficient home.

Links:

For an introduction to passive design and to access design guide sheets

www.greenenhouse.gov.au - Passive design introduction

A solar housing development in WA Housing of the Future: Ellenbrook Solar Housing

Solar Technology Designers Manual - http://www.unisun.com.au/

Books:

Garry Baverstock & Sam Paolino (1986) Low energy buildings in Australia :a design manual for architects & builders. This excellent publication gives angles to maximise or minimise winter and summer sun for all locations in Australia.

Text Box: Download and print an energy estimation sheet http://www.unisun.com.au/table.pdf

Text Box: TRY THIS SOLAR DESIGN QUIZ
Dr. Bob Rich - A quiz about solar efficient house design

Minimising energy use and waste during construction: reduce, reuse and recycle.

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“Australians generate approximately one tonne of waste per person per year, which goes to landfill. Up to 40 percent of this is building waste. Minimising and recycling this waste can have significant social, economic and environmental benefits.”

Source: Good Residential Design Guide - Your Home - Waste Minimisation

The aim is to reduce waste and energy use, reuse where possible materials such as off cuts, and build with an aim to recycle. This can be achieved by using locally made products to reduce added energy costs due to transportation and carefully planning the building based on material availability and specifications. For example, Optimize building dimensions to correspond to standard timber dimensions thereby reduced energy and time used in sawing/milling and using off-cuts for other construction needs.

The Centre of Excellence in Cleaner Production at Curtin University Western Australia has produced eighteen guidelines for minimising waste in residential construction which are available for download and distribution.

Fact sheets on a variety of product waste and recycling processes can be found at http://www.wastewise.wa.gov.au

Construction Materials

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When building sustainably the choice of construction material will contribute significantly to the overall sustainability rating of the home. For instance using a material like steel that has a high embedded energy may detract significantly from overall energy rating of a home whereas using plantation timber that has a moderate embedded energy rating may have a minimal impact on a homes overall energy rating. However, using steel in a totally solar/passive house may not be an issue if the design allows for maximum energy efficiency and savings over its life cycle. Each design needs to be assessed on its overall performance over its lifetime rather than on a single criteria or issue.

As an example Sustainable Earth Technologies show the advantages of using one building material over another.

Mudbrick has several advantages over conventional fired clay or concrete masonry. The advantages include:

· Low in embodied energy

· Utilisation of natural resources and minimal use of manufactured products

· Good sound absorption characteristics

· High thermal mass

· A claimed ability to "breath"

· Suited to a wide range of soils

· Easily manufactured and worked

· Flexibility in design/colour/surface finishes

· Insulation properties similar to those of concrete or brickwork

Source: http://www.sustainable.com.au/construction.html

The choice of building materials you use may be determined by the following factors: availability, cost, suitability and feasibility. The following are items for consideration when choosing building materials. Click here for a construction systems overview.

Using materials that are or can be recycled

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Taking a life cycle view of a building, materials used in construction should have a high recycling potential at the end of the buildings life. They should also be non-toxic ensuring safety in the demolition and recycling stages. Using recycled products may be efficient and cost effective in an owner-builder situation or individual buildings, but complications arise due to consistency and availability of materials when considering mass produced or housing development homes. In this case steps should be taken to use materials from a renewable source such as locally produced plantation timber or materials that are manufactured using recycled content. There are a number of tools available designed to assist with the sourcing of sustainable materials. Ecospecifier is one such tool which has sustainable information available on a large range of building related products and materials.

Note: Germany is a world leader in recycling and has a program in place aimed at recycling every part of a manufactured product including motor vehicles and building materials.

Links:

Good Residential Design Guide - Your Home - Waste Minimisation

http://www.recyclingtoday.com

http://www.greenbuilder.com/sourcebook/constructionwaste.html

http://onsite.rmit.edu.au/home.htm - Contains excellent information and links page on waste management

Using materials made from a renewable source and are locally sourced

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Using renewable products such as timber from ecologically sustainable plantations or straw grown in a sustainable production system,(no pesticides, fertilisers etc.), will reduce strain and demand on precious non-renewable resources.

Sourcing materials locally reduces energy costs associated with packing and transport as well as assisting your local business community.

Click here to go to a list of WA suppliers

Using materials that have a low embedded energy rating

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“Energy is needed not only to run a building - it also takes energy to create the building products and build it. Put at its simplest, embodied energy is the energy needed to transform a product from raw materials in the ground to the final article. The embedded energy of a building is therefore the total energy required to construct it - that is to win the raw materials, process and manufacture them as necessary, transport them to site and put them together. It is the energy that has “gone in with the bricks” and which cannot be recovered during the lifetime of the building, no matter how efficiently it operates.”

Source: Sustainable Homes: Embedded Energy Report Page 4

It is useful to decrease the amount of embodied energy going in to a building. However, it is generally considered good practice if there is a slight increase in embodied energy due to the use of materials/appliances/fittings etc. if there is a significant return in energy savings. For instance using some forms of concrete, which has a moderate to high embodied rating, can return energy saving through its thermal properties, e.g. the stored warmth from the sun which can be returned at night for heating.

An in depth report on common building materials including embedded energy research can be found here: Which is better? steel, concrete or wood: a comparison of assessments on three building materials in the housing sector.

Buying locally made products can offset embodied energy through savings in transport costs, fuel usage and emission outputs.

More information on embedded energy can be found here

Reducing the embodied energy of buildings

Using energy rated and efficient fittings

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Electrical Appliances

Australia has adopted the Energy Star rating for electrical appliances.

“ENERGY STAR is an international standard for energy-efficient electronic equipment. It was created by the US Environment Protection Agency (EPA) in 1992 and has now been adopted by several countries around the world, including Australia.

In Australia, Commonwealth, State and Territory Government agencies are cooperating through the National ENERGY STAR Program to encourage the use of energy-efficient equipment at home and in business (see Promoting ENERGY STAR)”

Potential for savings

“If the energy-saving features were activated on all ENERGY STAR compliant computers in Australia, this would: save around $228 million each year in electricity costs cut annual greenhouse gas emissions by over 2,280,000 tonnes (CO₂ equivalent); this would be like taking more than 500,000 cars off the road!

If all the TVs sold in a year in Australia were ENERGY STAR compliant, this would save around $936,000 in electricity costs cut annual greenhouse gas emissions by over 9,360 tonnes (CO2 equivalent).”

Source: http://www.energystar.gov.au/what.html

Energy saving calculators and links

Energy saving Calculator

http://www.energystar.gov.au/

For energy rating information on domestic electrical appliance go to

http://www.energyrating.gov.au/

Water saving

Water use in the home can be dramatically reduced with by recycling greywater, redirecting stormwater, composting toilets, rainwater tanks and triple A rated and above fittings and appliances.

The Water Services Association of Australia is implementing the National Water Conservation Rating and Labelling Scheme which covers such items as Shower heads, Dishwashers, Clothes washing machines, Taps and tap outlets, Toilet suites or matched cistern and pan sets and Flow regulators.

There rating system uses a 5A rating scheme. The more A’s the higher the water efficiency. Minimum standards for fittings should be triple A or higher. The West Australian State Government has introduced the waterwise rebate program which gives rebates for a number of approved water saving products and systems.

Products rebates include; waterwise tap timers, AAA-rated in-tap flow regulators, soil wetting agents, greywater re-use systems and aerobic treatment units, AAA-rated showerheads, AAAA-rated washing machines, rainwater tanks and garden bores.

System rebates include; garden bores, rainwater tanks, greywater reuse systems and aerobic treatment units.

Click here for a list of showerheads that are AAA rated.