House Energy Rating
Encyclopedia
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
and State governments (NSW, SA, Tasmania, Victoria) and by private investors.
Under FSDR, the basic elements of glass, mass and insulation were the basis of the design principles of a five star home. The building industry did not widely accept the system due to its simple pass/fail rating and its restrictive guidelines.
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.
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, 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
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
South Australia
South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...
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:
- 5 Star energy rating for the building fabric, and
- A rainwater tank for toilet flushing or a solar hot water system, and
- Water efficient shower heads and tapware.
During 2006, requirements for 5-star energy ratings were introduced for new homes through the BCA in Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
and the Australian Capital Territory
Australian Capital Territory
The Australian Capital Territory, often abbreviated ACT, is the capital territory of the Commonwealth of Australia and is the smallest self-governing internal territory...
. As of mid 2007 Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
, Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
and the Northern Territory
Northern Territory
The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...
have not adopted 5 star requirements for new homes. New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
has not adopted requirements under the BCA and operates its own Building Sustainability Index or BASIX
BASIX
BASIX or Building Sustainability Index is a scheme introduced by the government of New South Wales, Australia in 2004 to regulate the energy efficiency of residential buildings. It offers an online assessment tool for rating the expected performance of any residential development in terms of water...
. Victorian consumers and building practitioners can find out more about the 5-Star energy ratings by visiting Make Your Home Green – Building Commission
History
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 FederalGovernment of Australia
The Commonwealth of Australia is a federal constitutional monarchy under a parliamentary democracy. The Commonwealth of Australia was formed in 1901 as a result of an agreement among six self-governing British colonies, which became the six states...
and State governments (NSW, SA, Tasmania, Victoria) and by private investors.
Under FSDR, the basic elements of glass, mass and insulation were the basis of the design principles of a five star home. The building industry did not widely accept the system due to its simple pass/fail rating and its restrictive guidelines.
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.
6-Star rating
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.5-Star rating
Building performance
Building performance or home performance is a comprehensive whole-house approach to identifying and fixing comfort and energy efficiency problems in a home....
, 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
Energy audit
An energy audit is an inspection, survey and analysis of energy flows for energy conservation in a building, process or system to reduce the amount of energy input into the system without negatively affecting the output.-Principle:...
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
Weatherization
Weatherization or weatherproofing is the practice of protecting a building and its interior from the elements, particularly from sunlight, precipitation, and wind, and of modifying a building to reduce energy consumption and optimize energy efficiency.Weatherization is distinct from building...
testing is not required as it is with the regulations in the UK.
Software
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
Controversies
- The rating system does not consider factors such as sustainable materials, embodied energy, electricity sources, rainwater capture, local vegetation and access to public transportation.
- Some say that Carbon emissions would be a better metric to use compared to raw MegaJoules of Energy consumption.
- Inaccurate representation of the building in the software can result in an inaccurate assessment of the building's thermal performance. An unskilled or inexperienced assessor can easily make incorrect asssumptions. Some states require in-depth training & accreditation for all assessors before they are considered qualified to use the software, while other states merely highly recommend (but not require) in-depth training & accreditation.
- While not a fault of the software itself, a building is often not constructed as drawn on the plans and some items (weather sealing, insulation values, window coverings, paint colours, etc.) are often different from what was originally simulated. In other unintentional cases, items are installed but are installed incorrectly in a way that compromises their thermal performance (such as foil-based insulation without an air gap).
- In rare cases, certain styles of buildings in certain climates have become very difficult to comply without using expensive materials (such as a house on the side of a hill with solid glass walls along three sides, to provide ample viewing of the natural scenery). While most buildings can still find a solution without any major design alterations, sometimes this is only possible with expensive materials and this drastically increases the price of the house. This is usually an indication that the building was designed with aesthetics taking a prominent position over the comfort & livability of the occupants.
- The rating system does not deal with problems beyond a single household such as urban sprawl, city planning, etc.
State Government initiatives
- ACTAustralian Capital TerritoryThe Australian Capital Territory, often abbreviated ACT, is the capital territory of the Commonwealth of Australia and is the smallest self-governing internal territory...
House Energy Rating Scheme (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.
- In Victoria all new homes built since 2005 are required to achieve a 5 Star rating. Rating can be performed using any software approved by NatHERS.
- In South AustraliaSouth AustraliaSouth Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...
, all new homes (and alterations to existing homes) are required to achieve a 6 star rating. This requirement was introduced on 1 September 2010.
- 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.
- In QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
it is proposed that from either the 1st January 2009, or when the Building Code of Australia 2009 update is released in May 2009, that all new homes built in Queensland will be required to achieve a 5 star energy equivalent rating. Currently the minimum requirement is 3.5 stars.
See also
- Green Star (Australia)Green Star (Australia)Green Star is a voluntary environmental rating system for buildings in Australia. It was launched in 2003 by the Green Building Council of Australia....
- BASIXBASIXBASIX or Building Sustainability Index is a scheme introduced by the government of New South Wales, Australia in 2004 to regulate the energy efficiency of residential buildings. It offers an online assessment tool for rating the expected performance of any residential development in terms of water...
, (NSW) - EnerGuide for Houses (Canada)
- National Home Energy RatingNational Home Energy RatingThe National Home Energy Rating Scheme is both a UK accreditation scheme for energy assessors and a rating scale for the energy efficiency of housing.The NHER is owned and operated by National Energy Services...
(UK) - Home energy ratingHome energy ratingA Home Energy Rating is a measurement of a home’s energy efficiency, used primarily in the United States. Home energy ratings can be used for either existing homes or new homes. A home energy rating of an existing home allows a homeowner to receive a report listing options for upgrading a home’s...
(United States) - Energy conservationEnergy conservationEnergy conservation refers to efforts made to reduce energy consumption. Energy conservation can be achieved through increased efficient energy use, in conjunction with decreased energy consumption and/or reduced consumption from conventional energy sources...
- Environmental economicsEnvironmental economicsEnvironmental economics is a subfield of economics concerned with environmental issues. Quoting from the National Bureau of Economic Research Environmental Economics program:...
- Green buildingGreen buildingGreen building refers to a structure and using process that is environmentally responsible and resource-efficient throughout a building's life-cycle: from siting to design, construction, operation, maintenance, renovation, and demolition...
- Zero-energy building
- Low-energy houseLow-energy houseA low-energy house is any type of house that from design, technologies and building products uses less energy, from any source, than a traditional or average contemporary house...
- Passive housePassive houseThe term passive house refers to the rigorous, voluntary, Passivhaus standard for energy efficiency in a building, reducing its ecological footprint. It results in ultra-low energy buildings that require little energy for space heating or cooling. A similar standard, MINERGIE-P, is used in...