The Western Australian Government is committed to efficient use of energy throughout the State.

As part of this commitment, Western Australia is a party to the National Strategy on Energy Efficiency, a Council of Australian Governments (COAG) measure to accelerate energy efficiency efforts that are already underway and introduce new measures to improve energy efficiency throughout the economy.

Part of this strategy is to increase the minimum energy efficiency standards for all new buildings in the Building Code of Australia (BCA). The new provisions were included in the BCA 2010 edition. This included an increase in the minimum energy efficiency standard for new housing from 5 stars to 6 stars.

What is 6 star?

The energy efficiency of houses is measured through a star-rating system, with the worst performing buildings achieving a zero rating through to a 10-star rating for a building that needs no artificial heating or cooling.

A rating is done through the use of computer software modelling aligned to a protocol administered by NatHERS (Nationwide House Energy Ratings Scheme). This determines the potential heating and cooling requirements of a given house design. It takes into consideration various features, such as orientation of the house, shading, window placement and size, climate, ventilation, insulation, materials used and roof colour.

The BCA also has a set of deemed-to-satisfy solutions that are considered equivalent to a 6 star rating. These solutions can be used instead of a software rating.

In addition to the 6 star rating for heating and cooling, the BCA requires all houses to meet new lighting efficiency standards.

These requirements also apply to any renovations or extensions that require a building licence as is the case for the current energy efficiency requirements.

What are the benefits of 6 star?

A house built to a 6 star standard will use about 20 to 25% less energy to heat and cool when compared to a similar sized 5 star house.

This will reduce your energy bills and will reduce the burden on the State’s energy infrastructure. It will also help reduce carbon emissions and free up household finances for other uses.

If you intend to install a renewable energy system, you can expect it to meet more of your household energy needs in a 6 star house as the house will use less energy for heating and cooling. This will reduce your electricity bills even further and help pay back your renewable energy system more quickly.

How do I achieve 6 star?

An increase in energy efficiency doesn’t necessarily mean an increase in building cost. If you get the basics right, and design the house well from the outset, there should be minimal additional costs. For houses priced about $200,000 or below, the price increase is likley to be a maximum of about 2% or as low as 0.2%, according to local independent research.

Firstly, align your house to allow your living areas to face north. With appropriate shading, this will allow winter sun to warm your house, but blocks the heat from the summer sun. Getting this right can add up to 1 star to the rating on its own.

Once you have this foundation to work from, your architect, building designer or builder can help you through the rest of the design to ensure it reaches the 6 star standard.

When will 6-star be introduced?

From 1 May 2011 the 6 star requirements will be available in Western Australia. However, to allow time for consumers and builders to get used to the new requirements, there will be a 12-month transition period. Over this time the current requirements, as set out in the BCA 2009 edition, will be acceptable.

From 1 May 2012, the 6-star requirements (including lighting efficiency) will be mandatory. The hot water system requirements in the BCA will supersede the 5 Star Plus requirements for hot water systems. The other 5 Star Plus Water Use requirements will still apply.

Is 6-star only required in new homes?

Yes. These new requirements are only for new residential buildings. This is because achieving this higher standard is much easier and cheaper when building new homes. For instance, the orientation is a key component of a high performance house and can only be implemented at the design stage of a new build.

Also, new buildings become our existing building stock. Not building high performance buildings now will only add to the legacy of low performance buildings that the community has to deal with in the future. It is estimated that 20% of the housing stock in WA in 10 years’ time is yet to be built.

Other policies are being developed to address the energy use in existing buildings.

Due to constantly evolving legislation the information provided within this blog may no longer be valid. The advice given on this site is general in nature and does not take into account your specific circumstances. Please email one of our building surveyors to check what is right for you.

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