A House Energy Rating is an index of a building's thermal performance (i.e. heating and cooling requirements) for residential homes in Australia. The Australian Building Codes Board introduced energy efficiency measures for houses into the Building Code of Australia (BCA) on 1 January 2003. It has been adopted by all Australian states and territories which did not already have an equivalent system in place. Victoria and South Australia have gone beyond the standard, and mandated, instead of 4-stars, a 5-star rating (enacted July 2004) - all new homes and apartments built in Victoria must comply with the 5 Star standard. This means it is compulsory for new houses to have:
During 2006, requirements for 5-star energy ratings were introduced for new homes through the BCA in Western Australia and the Australian Capital Territory. As of mid 2007 Tasmania, Queensland and the Northern Territory have not adopted 5 star requirements for new homes. New South Wales has not adopted requirements under the BCA and operates its own Building Sustainability Index or BASIX. Victorian consumers and building practitioners can find out more about the 5-Star energy ratings by visiting Make Your Home Green – Building Commission
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The Five Star Design Rating (FSDR) was an award developed in the 1980s for "high efficiency through excellence in design and construction" which assisted builders in marketing energy efficient home designs. The certification was developed by the Glass, Mass and Insulation Council of Australia (GMI Council) together with CSIRO Division of Building Research. The GMI Council was funded by Federal and State governments (NSW, SA, Tasmania, Victoria) and by private investors.[1]
Under FSDR, the basic elements of glass, mass and insulation were the basis of the design principles of a five star home.[2] The building industry did not widely accept the system due to its simple pass/fail rating and its restrictive guidelines.[3]
In the 1990s, individual states developed their own schemes. The Victorian scheme, based on a computer program, was eventually accepted as the most effective. However, it worked poorly in warm humid climates such as found in Queensland. The development of a nationwide House Energy Rating Scheme (NatHERS) began in 1993, based on the Victorian scheme, using the CHEETAH / CHEENATH engine developed at CSIRO. Software products NatHERS, FirstRate and Quick Rate, BERS, Q Rate and ACTHERS are based on this engine. NatHERS and BERS run the engine directly, while others use correlations based on the engine.[3]
A 6-Star rating indicates that a building achieves a very high level of thermal energy performance. As of November 2011, 6-Star equivalence is the current minimum requirement in most of Australia.
A 5-Star rating indicates that a building achieves a high level of thermal energy performance, and will require minimum levels of heating and cooling to be comfortable in winter and summer. Houses which achieve a 5 star rating, compared to the average 2 star home,[4] should be more comfortable to live in, have lower energy bills, and costs to install heating and cooling equipment should also be lower.
Energy assessments take into account different climatic conditions in different parts of the country and are benchmarked according to average household energy consumption particular to a given climatic region.
The house energy rating does not currently include the efficiency of any appliances fitted or used within the house. There are also no physical testing requirements, so air tightness testing is not required as it is with the regulations in the UK.
One of the best ways to achieve an energy rating on a proposed house is by using House Energy Rating Software (HERS). This kind of software will simulate a home and provide estimates for the energy needed to heat and cool that home over the course of the year.
The Nationwide House Energy Rating Scheme (NatHERS) is a framework by which this kind of software is assessed, compared and accredited for use in Australia.
The First Generation of accreditation included the FirstRate 4, BERS 3.2 and NatHERS software packages, allowing accredited assessor to use this software to provide energy ratings.
The Second Generation of accreditation was tightened and improved, meaning that software had to become more precise, accurate and powerful in response. The Second Generation of software must take into account more features and realistically model elements such as natural ventilation, the cooling effects of ceiling fans, under-floor heating and the effects of attached dwellings such as apartments.
The First Generation has been phased out for the Second Generation of software to take over.
In Victoria, the First Generation of software was no longer acceptable for energy ratings after the 30th of April, 2009. FirstRate is the software package developed by Sustainability Victoria. Over the course of 2008, Sustainability Victoria has produced a new version, FirstRate 5.
FirstRate 5 received provisional Second Generation accreditation on 31 August 2007. This means that it can be used for house energy ratings now. From May 2009, it will be the only version of FirstRate accredited for use in Victoria. FirstRate Five uses the AccuRate calculation engine with a graphic interface. It includes: the ability to zone the house according to how each room will be used, the ability to rate up to 10 stars and the full range of AccuRate climate zones (69 in Australia).
Other Second Generation software acceptable for use in Victoria now and after the 30th April deadline includes BERS Professional and AccuRate. AccuRate shares a calculation engine with FirstRate 5 but has a more complete data input method which allows for more precise energy ratings but lacks FirstRate5's graphic interface. Each software package will be appropriate in different circumstances.Nationwide House Energy Rating Scheme (NatHERS) - Home Page
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