- House Energy Rating
A House Energy Rating is an index of energy efficiency 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 Australiahave gone beyond the standard, and mandated a 5-star rating, instead of 4-stars. During 2006, requirements for 5-star energy ratings were introduced for new homes through the BCA in Western Australiaand the Australian Capital Territory. As of mid 2007 Tasmania, Queenslandand the Northern Territoryhave not adopted 5 star requirements for new homes. New South Waleshas not adopted requirements under the BCA and operates its own Building Sustainability Index or BASIX.
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
CSIRODivision of Building Research. The GMI Council was funded by Federal and State governments (NSW, SA, Tasmania, Victoria) and by private investors. [Energy Efficient Building Design, Resource Book. 1992. Holger Willrath. Brisbane Institute of TAFE. Unit 1.]
Under FSDR, the basic elements of glass, mass and insulation were the basis of the design principles of a five star home. [Ballinger, J. A. (1998). The Nationwide House Energy Rating Scheme for Australia (BDP Environment Design Guide No.DES 22). Canberra: The Royal Australian Institute of Architects.] . The building industry did not widely accepted the system due to its simple pass/fail rating and its restrictive guidelines.Development of a new framework for a House Rating Scheme (HRS) Maria Kordjamshidi. August 1997. University of New South Wales. [http://www.library.unsw.edu.au/~thesis/adt-NUN/uploads/approved/adt-NUN20071003.110139/public/] ]
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 (HERS) 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.
A 5-Star rating indicates that the house has achieved 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, 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.
For calculating the efficiency of a house, the software tools used are NatHERS (the Nationwide House Energy Rating scheme/software, which is to be replaced by the CSIRO's AccuRate), BERS and FirstRate. Which software packages and versions are approved varies from state to state. While FirstRate only gives ratings up to 6, AccuRate will report up to 10 stars. [http://www.greenhouse.gov.au/yourhome/technical/fs110.htm]
*The rating system does not consider factors such as sustainable materials, electricity sources, waste treatment and transportation to, from and within urban environments.
*There are a number of ways the user of the FirstRate software can cheat the program to achieve higher star ratings, many such techniques have been learned by TAFE students as they learn the program, it is not difficult to learn and requires only selecting particular variables whose values are inherently inaccurate.
*Keeping the above in mind, some elements such as draught strips, insulation, etc can be selected in FirstRate but may never be included in the final drawings. In many cases, builders do not install particular systems properly, this combined with many other factors means that the completed building can be sometimes have a rating of up to 3 stars different from its initial rating.
*The legislation was passed before there was actually a method to rate the buildings, the software was rush released and as a result is inaccurate and inappropriate.
*The ratings were seen as a quick short-term answer to a problem that the government at the time had to deal with and as a result, no long term solution exists and the problem itself remains mostly unsolved.
*Large companies such as Simmonds, AV Jennings, etc, have been accused of cheating the rating system to achieve higher stars to market their pre-built product homes as more environmentally friendly.
*The rating system does not deal with many of the problems inherent in low-density urban environments.
*FirstRate and the Green Star system has been the subject matter of a prolific running joke within the building industry within Metropolitan
Melbournesince its creation, and has become synonymous with issues government inaction and short-sightedness in the industry.
*Many explainwho that the anti-progressive nature of Australia's building industry requires tough action and long-term solutions when dealing with issues of sustainability to counter ingrained attitudes.
Australian state-based initiatives
*ACT House Energy Rating Scheme (ACTHERS) [http://www.actpla.act.gov.au/design-guide/acthers/] , requires new or previously lived in residential homes to have an Energy Efficiency Rating (EER) Statement, prepared by an accredited ACTHERS assessor, if they are to be sold. As of the February 2006, the required software used in assessment is
FirstRate, Version 3.1 or Version 4. [http://www.actpla.act.gov.au/design-guide/acthers/eer_sell.htm]
*In Victoria, since July 2004, all new homes are required to achieve a 5 Star rating. [http://www.sustainable-energy.vic.gov.au/seinfo/your-home/Home%20building%20and%20design/energy%20rating%20and%205%20star/index.asp] A 5 star rating can be achieved for the building fabric alone, or through a 4-star rating (based on building fabric) combined either a
rain water tankconnected to all flush toilets or a solar hot water system. There are two approved software packages: FirstRate and NatHERS.
* In South Australia, all new homes (and alterations to existing homes) are required to achieve a 5 star rating. This requirement was introduced on
1 May 2006. [http://planning.sa.gov.au/index.cfm?objectid=1F05999B-96B8-CC2B-691B6F3A96013410]
* Western Australia: in 2007 the WA Government introduced further energy and water usage regulatory requirements. 5 Star Plus consists of two codes: the Energy Use in Houses Code, which requires a minimum standard of energy performance for a hot water system; and the Water Use in Houses Code, which includes provisions for alternative water supplies, efficient fixtures and fittings, and grey water diversion.
BASIX, NSW Government's Building Sustainability Index[http://www.basix.nsw.gov.au/]
EnerGuide for Houses(Canada)
Home energy rating(United States)
National Home Energy Rating(UK)
Wikimedia Foundation. 2010.