Sustainable and energy-efficient homes

An energy-efficient house uses natural heating and cooling to be comfortable all year. Sustainable houses are cheaper to run because they use less energy. They also improve wellness in the home and reduce the house’s environmental impact.
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Information for homeowners

Some houses seem to be cool in summer and bathed in winter sunshine. This is not just luck; it is achieved with energy-efficient design.

Below are some tips to consider when building your home.

Choosing your block

A well-designed house has living areas to the north, bedrooms to the east or south and utility areas, such as laundries and bathrooms, to the west. Consider this orientation when choosing your block. Getting any of these elements right will make the house more comfortable and you will be less reliant on artificial heating and cooling.

Windows

Getting the windows in your home right is vital to make it energy efficient.

Window design, glazing and insulation treatments, as well as placement and orientation, all play important roles.

In the southern half of Western Australia, you want to control the amount of sunlight coming through the windows on the east and west sides of your home.

Try to locate the windows on the north side of your home and consider shades for all your windows to block out the summer sun, but allow sunlight in over the winter months.

Correctly located windows allow cool breezes through your home in summer. Good insulation keeps your home at a comfortable temperature year-round.

In the northern half of WA, controlling heat gain on all sides of the home is the primary consideration.

Building design

New homes must meet the energy-efficiency requirements of the Building Code of Australia (BCA).  The ‘Information for practitioners’ section below provides more detail. Your builder can explain the minimum energy efficiency standards which apply to your home.

NatHERS star ratings estimate the heating and cooling needs of a home. A star rating is out of 10 and considers a home’s design, orientation, construction materials, and the local climate.

If your design was assessed using NatHERS Software, the NatHERS rating certificate shows the rating of the design.

If you want to go further, you can find builders and designers who specialise in sustainable and energy-efficient houses.

Solar PV panels

Over one third of Western Australian households already have solar PV systems, with numbers growing rapidly.

Residential solar PV systems can be grid-connected or stand-alone.

Grid connect systems enable surplus power not used by the household to be fed back into the main power grid. When the panels are not producing power at night or reduced output on cloudy days, power is drawn from the grid.

Hybrid systems incorporate connection to the grid as well as battery storage. Surplus power generated charges the battery. Once the battery is fully charged, excess power is fed into the grid. When the solar panels are not generating power, the battery supplies power until its charge level is low, when the grid resumes supply.

Stand-alone systems are not connected to the grid. Any surplus power generated by solar PV is stored in a battery for later use to maximise savings.

View further information on the safe maintenance and use of solar PV panels at th elink below.

Safe use of solar PV panels

  • Your Home
    A guide to environmentally sustainable homes
  • NatHERS
    Nationwide House Energy Rating Scheme
  • Water Corporation
    Tips on reducing water wastage
  • Josh’s House
    Showcases the benefits of sustainable housing to the community through demonstration and inspiration
  • Consumer Protection
    While Western Australia has a great climate for residential solar PV systems, other factors affect the value of your system

Information for practitioners

The energy-efficiency requirements for housing (Class 1 buildings and certain Class 10 buildings and structures) are contained in the BCA Volume Two, which forms part of the National Construction Code (NCC). The performance requirements for new housing consider both the thermal performance of the house and performance of its regulated domestic services.

The BCA is available free online from the Australian Building Codes Board.

Options to comply with the requirements

The energy efficiency Performance Requirement for a house can be met through deemed-to-satisfy (DTS) provisions (Part H6D2 of the BCA) or the use of a performance solution (Part A2G2).

Deemed-to-satisfy

The DTS provisions contain two compliance options:

  1. Energy rating in accordance with Specification 42;
  2. Elemental provisions in accordance with Part 13 of the ABCB Housing Provisions Standard.

Western Australia additions

The BCA Schedule 11, State & Territory Appendices has additional provisions for water use in WA houses.

Performance solutions

A performance solution must be prepared in accordance with Part A2G2 of the BCA and demonstrate compliance with the relevant Performance Requirements using one or more of the following assessment methods:

  • Evidence of Suitability in accordance with NCC Part A5;
  • Verification Method, which for H6P1includes H6V2VURB;
  • Other Verification Method that shows compliance with the Performance Requirements to the satisfaction of the certifying building surveyor;
  • Expert Judgement; and
  • Comparison with the DTS Provisions.

Check sheets

Building and Energy no longer provides verification sheets or check lists to assist with energy efficiency assessments. The BCA 2012 check sheets and tools previously available on our website for new houses are outdated and should not be used.

Documentation of decisions

Decisions made under the BCA should be fully documented and copies of all relevant documentation should be retained.

Examples of the documentation which should be prepared and retained include:

  1. Details of the Building Solution including all relevant plans, specifications and other supporting documentation.
  2. Where a Performance Solution is included, A2G2(4) requires a comprehensive performance-based design brief, including:
  • a summary of the proposal
  • a description and explanation of the proposed solution
  • nominated applicable Performance Requirement(s)
  • agreed analytical assessment processes
  • agreed acceptance criteria
  • required scope of supporting evidence
  • format and content of the final report
  • acknowledgement of participants.

It is the responsibility of the registered building surveyor to request sufficient documentation to be satisfied the building will meet the relevant performance requirements.

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