Will Tasmania finally get with the Energy Efficiency times?
It’s now getting close (we hope), since the ‘sidestep’ when the Tasmanian Government back in 2011 put off the introduction of the mandatory 6 star energy efficiency guidelines to come in-line with the rest of Australia and told Building Designers, Architects and Energy Raters that it wouldn’t happen until May 2013.
ABSA wrote about the governments decision back in 2011 and expressed their disappointment as we all did at the time.
Well it’s now only a couple of months away, and after a few of the ‘experiments’ around xmas with accredited raters only to do energy ratings we hope this is a big step forward for Tasmania’s New Housing Stock as the rules get tighter and houses are using less energy to heat and cool their houses.
This taken from the Workplace standards website confirms it’s still going ahead.
Tasmania has required mandatory energy efficiency measures for new housing for a decade (since 1 January 2003).
Since 2009 a “5 Star” requirement under the Nationwide House Energy Rating Scheme (NatHERS) has applied under the Building Code of Australia (BCA). New Tasmanian buildings will require a higher “6-Star” standard in 2013.
When do the new “6-Star” requirements commence?
From 1 May 2013 all new homes and extensions built in Tasmania will need to achieve a 6-Star level of energy efficiency when the National Construction Code 2013 comes into force. The existing variation to the National Construction Code which applies the standard of the 2009 edition will then be removed.
What types of buildings do the “6-Star” requirements apply to?
- All Class 1 buildings (detached house, unit or town house)
- All Class 2 buildings (apartments) and
- Class 10a buildings (such as garage) that have a conditioned space (heated or cooled) attached to a Class 1 building.
The 6-Star requirements also apply to new work on an existing residential building such as additions, extensions and alterations.
What are the main changes introduced by the “6-Star” requirements?
- more insulation is needed to meet increased minimum R values
- more stringent glazing provisions
- compensation for ceiling insulation loss from openings such as exhaust vents and downlights
- new requirements for fixed lighting.
Achieving the “6 Star” level
“6 Star” refers to the required level of thermal performance for the building. That level can be achieved by either:
- complying with the relevant elemental Deemed-to-Satisfy Provisions in the BCA; or
- achieving an energy rating of not less than 6 Stars using house energy rating software that complies with the National House Energy Rating Scheme (NatHERS); or
- reducing the heating or cooling loads (verified by energy rating software) and complying with specific energy-saving features such as the testing and installation of insulation, thermal breaks, compensation for downlights, floor edge insulation and building sealing.
How is compliance with “6-Star” verified?
The Building Act 2000 requires a permit for new building work to ensure it will comply with the National Construction Code (NCC). The design of new homes and extensions is assessed against the NCC by a building surveyor for the issue of a Certificate of Likely Compliance. This assessment includes checking for compliance with the 6-Star energy efficiency requirements.
Who can perform an energy assessment for “6-Star”?
An energy assessment of new homes and extensions can be completed by the responsible designer (an accredited architect or an accredited building designer) if they are competent. That is part of their work as an accredited designer.
- An energy efficiency assessment may be made using the Deemed-to-Satisfy approach (prescriptive construction requirements for thermal comfort) in the NCC; or
- Energy efficiency may also be verified using a computer-based energy rating program operating approved “second-generation” software. A printed vertification report, signed and dated and the supporting documentation must be provided to the building surveyor.
An expert house energy assessor, who is not the responsible designer, can also undertake energy rating assessments using the approved software. They must provide a verification report, supporting documentation and complete a Form 55 “Certificate of Specialist or Other Person” to provide to the building surveyor. However the Form 55 can only be accepted by a building surveyor if that energy assessor is accredited by either:
- ABSA (the Association of Building Sustainability Assessors); or
- BDAV (the Building Designers Association of Victoria).
There is no requirement that an independent energy assessor must also be accredited under the Building Act 2000 as a building practitioner in Tasmania.
Approved Assessment Software
Only the Second-Generation NatHERS Thermal Assessment Software which complies with the NatHERS acreditation protocol dated June 2012 may be used to determine compliance with the NCC. They are:
- AccuRate or AccuRate Sustainability
- FirstRate
- BERS Professional
AccuRate is Australia’s national benchmark software tool and was designed by the CSIRO. BERS Professional and FirstRate 5 provide building professionals with alternative user interfaces. All software tools use the same calculation engine (Chenath Engine).
Software and training is available from commercial providers.
Can designs prepared before 1 May 2013 still be accepted?
From 1 May 2013 all new residential designs must be to the 6-Star requirements. If substantial progress had been made on a design before this date, the previous (lower) standard of 5-Star may still be accepted under the transitional provision provided in section 55(4)(b) of theBuilding Act 2000. However the use of this transitional provision is not recommended because there has been a long lead up to introducing 6-Star. The decision to change has been known by industry since November 2011 and the extra time was to allow building practitioners to become familiar with the altered requirements.
Designing and constructing a “6-Star” energy efficient house
Designing and constructing a new home or extension to be 6-Star energy efficient will cost much less than attempting to refit an existing building. That is why the 6-Star requirement is mandatory for new work at the design or construction stage.
Homes incorporating sound environmental design principles can minimise heating and cooling bills and have a lasting positive impact on the environment by reducing greenhouses gases. Some of these principles include:
- site responsive design and appropriate house zoning orientation
- well insulated wall, floor and ceiling
- thermally efficient windows
- northerly orientation to gain maximum advantage from solar energy
- internal and external shading of windows and walls in summer.
Consider the climate zone location
The 6-Star energy efficiency requirements depend on the climate zone in which a house is located. Climate zones are determined on climatic data and there are two Tasmanian zones:
- zone 7 (covering most of the state including the Bass strait islands)
- zone 8 (covering only alpine areas above 900 metres).
Consider the orientation of the house on the block
Good solar orientation of a house has the potential to achieve substantial energy savings when combined with an efficient design. Houses built with a north facing orientation for the main living areas are more likely to easily achieve a 6-Star rating.
Houses with large areas of glazing facing south, west or east may still achieve 6-Star but are then likely to incur higher construction costs and on-going heating costs for the occupants.
Consider the envelope of the house
The design and construction of the house’s envelope – roof, external walls and floors – will have an effect on the thermal comfort of a house. To achieve a 6-Star rating, the following is required:
- insulation of roofs and ceilings
- insulation under suspended floors
- selection of appropriate glazing systems (windows and doors)
- consideration of the number and size of roof lights (skylights) and ceiling penetrations including downlights
- sealing of openings and gaps to prevent draughts and covering of disused fireplaces.
Websites
- The Australian Building Codes Board (includes Tasmanian Climate Zone Map) www.abcb.gov.au
- Nationwide House Energy Rating Scheme (NatHERS) www.nathers.gov.au
- Commonwealth Government Department of Climate Change www.climatechange.gov.au
- Living Greener www.livinggreener.gov.au
- Tasmanian Government Energy Efficiency site “Earn Your Stars” www.climatechange.tas.gov.au
Find an independent energy assessor
- ABSA www.absa.net.au
- BDAV www.bdav.org.au
Lets hope for everyone there are no more delays, and when May comes around we can all start to bring a higher quality finish and energy efficiency to all the houses built in Tasmania.
