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Environmental rating tools are becoming increasingly important, but what is the experience of achieving a green building rating in practice? Ceridwen Owen of the University of Tasmania outlines the opportunities and complexities of gaining Green StarThe last decade has seen an almost meteoric rise in the range, sophistication and prominence of environmental rating tools for building developments. In line with the general move from energy efficiency to a more comprehensive and integrated understanding of “sustainability”, the trend within environmental rating tools is to provide a similarly complex assessment of environmental impacts within one framework, resulting in a single-point indicator. Two other trends can be identified within environmental rating tools: firstly, a focus on quantifiable outcomes; and secondly, a convergence of criteria and methodology.

This rationalization of environmental rating tools has advantages and disadvantages. On the positive side, it provides a common language of green buildings and facilitates comparison at a national and increasingly international level.

Universal benchmarking enables the integration of rating tools within the regulatory system as well as cross-comparison of projects within the market place. It is perhaps here that environmental rating tools have been most successful since there is no doubt that this benchmarking process has resulted in an increased awareness and demand for green buildings. Conversely, the exclusion, generalization and simplifications that inevitably arise within a standardized framework have led to some questions over the effectiveness of rating tools in the procurement of a sustainable built environment.

In Australia, the star has become the common currency of green buildings. Project briefs increasingly demand a five-star building, but there is frequently little understanding of what this means in practice. There are, of course, numerous assessment tools for different purposes. Some tools address only one specific environmental issue, most notably energy use, and most tools are related to only one specific building typology (see summary table). Within the commercial building sector, the stars of interest are the Australian Building Greenhouse Rating (ABGR) and Green Star, both of which have achieved wide industry acceptance and government support.

Green Star in particular has been responsible for a substantive shift in attitude towards and integration of environmental initiatives. Developed by the Green Building Council of Australia (GBCA) in conjunction with the Property Council of Australia (PCA), it provides an extensive assessment of environmental performance in the commercial building sector, encompassing the ABGR rating tool together with other issues of energy performance, management, indoor environment quality, transport, water, materials, land use and ecology, and emissions.

The freely downloadable tool can be used as a convenient checklist to guide decision-making in the design process. However, there is an enormous gulf between its use as a self-assessment tool and its primary purpose in providing certified ratings of environmental performance.

Specifically, Green Star was conceived to promote innovation in environmental building and to reward excellence within the top 25 percent of the market. Thus, no building can receive an accredited rating below four stars, which is seen to be equivalent to best practice. However, the enthusiastic adoption of Green Star by certain government authorities, such as the Melbourne City Council in its planning scheme, means that it is increasingly being used in a very different manner – as a minimum compliance tool. While in principle such actions are to be applauded for advancing sustainability in mainstream practice, in reality it leads to two key problems.

Firstly, the demand for Green Star accreditations has grown with such incredible speed that the individuals and organizations that support it are inevitably straining to keep up with demand. In the two years since the first certified rating was awarded, 17 projects have been accredited and 64 more are currently registered for certification. Since the GBCA must provide independent third-party verification by an accredited Green Star professional as part of the certification process, this puts enormous pressure on this relatively young organization. The Australian Environmental Labelling Association (AELA), which audits products in accordance with Green Star requirements for issues such as volatile organic compound (VOC) emissions and recycled content, is similarly flooded with requests from manufacturers.

While the response has been fast – and there are now more products than ever with substantiated environmental claims – there is still much work to be done. For architects specifying products that have not yet been audited, the process of proving environmental performance and claiming credits can be complicated and time-consuming.

The second and most problematic issue related to the use of Green Star as a compliance tool rather than as a tool to encourage environmental innovation in the building industry is the consequent tendency for “credit shopping”, in which the focus shifts towards getting a rating rather than achieving optimal environmental outcomes. Thus, there can be an over-emphasis on criteria that either represent best “bang for buck” or are easier to prove in practice.

Given Green Star’s intended role as a leadership tool, the GBCA has adopted a model where a substantial level of proof is required to verify a project’s environmental credentials. Approximately 150 pieces of separate documentary evidence are required to fulfil accreditation requirements for a five-star building. While some of this information is relatively easy to acquire, proving performance in other areas can be extremely difficult, even for the most committed project teams.

For example, to obtain a credit under reducing use of PVC (criteria Mat-7), the design team must demonstrate a 30–60 percent reduction in PVC use for benchmarked elements comprising all pipes, conduits and cables based on cost. To do this, itemized calculations from the quantity surveyor must be obtained with all standard and actual PVC uses in the project including any additions for floor coverings, blinds, window frames, cladding and finishes. In my experience, this is enough of a headache to discourage some project teams from working to achieve this aim. Conversely, the proof required for credits such as bicycle parking (Tra-3) to reduce transport impacts is relatively simple.

The rigour of the compliance requirements of Green Star frequently results in many environmentally appropriate initiatives being included in project developments that would otherwise be overlooked. However, it can also result in missed opportunities or, alternatively, the integration of initiatives with no real environmental benefit. For example, the use of Green Star on two projects in regional Victoria has resulted in many worthwhile initiatives being included that were not in the original brief, such as increased fresh air rates, indoor plants, CO2 sensing and automated blinds.

However, in order to get “over the line”, both developments have had to include bicycle parking in an area in which cycling to work is impractical.

These examples also illustrate the problems of working within a unified framework of environmental assessment that necessarily focuses on generalities rather than specifics. Given the substantial environmental impacts from private transport, Green Star understandably places a high degree of importance on the location of projects relative to public transport infrastructure. While in both of the above cases there were good reasons for the locations of the buildings outside major urban centres, this could not be assessed within the parameters of the tool. For rural and regional projects, the loss of this credit makes it much harder overall to achieve a five-star rating, and extremely difficult to achieve the highest six-star rating. The creation of “lighthouse projects” in smaller communities is an important social issue. However, it is difficult within the relatively rigid structure of environmental rating tools to assess such complex qualitative concerns.

The problems that arise from the generalized use of such tools in a compliance context are not easy to resolve. However, the benefits undoubtedly outweigh the drawbacks. One of the key advantages of rigorous accreditation programmes is the forcing of a more integrated design approach as a result of the complexity of the process. It is not feasible to achieve Green Star accreditation without the full support of the design team. This requires the early introduction of Green Star into the design programme, and regular workshops and meetings to provide updates and debate ongoing issues and to collect the documentation required for final submission.

This last point raises the issue of the financial burden of committing to a Green Star rating. It is impossible to generalize the capital costs of the environmental initiatives themselves. Inevitably a six-star building will result in greater up-front costs than a four-star building, but any initial costs must of course be considered in a life cycle context.

With respect to the Green Star rating process itself, however, the costs involved in obtaining certification are often underestimated. The direct cost for Green Star certification payable to the GBCA for independent third-party verification of documentation is only one small part of the total costs of pursuing a rating. By far the greatest costs are consumed in the consultant fees required to gather the volumes of evidence required for certification. For example, even the final collation, processing and printing of information can consume four weeks’ worth of work. In addition, the ongoing project meetings and workshops, continual documentation, interim reporting of rating status, and computer modelling required to meet certain criteria result in substantial time commitments from project team members.

Consultants to the GBCA are currently going through a process of estimating the relative financial burden of the Green Star assessment and accreditation process. While this is likely to vary substantially from project to project, as an indication, the fees for the Green Star professional consultant to provide general ESD advice and coordinate the accreditation process will likely be more than double the fee payable to the GBCA. In addition, the required computer modelling for thermal performance assessment, as well as other project-dependent criteria such as daylight modelling and acoustic assessments, results in considerable additional costs. In total, Green Star accreditation is likely to cost upwards of $50,000 for medium- to large-scale projects, and these costs are only exacerbated if an integrated design process and continual documentation of evidence are not undertaken from the beginning of the project.

The adoption of an integrated design process is the only way to achieve a successful outcome in the Green Star rating process. The substantial intellectual, financial and time commitments required from all members of the project team determine that everyone must be aware of the opportunities and complexities of undertaking a Green Star rating. This is best achieved by establishing a design workshop at the start of the project followed by regular meetings and workshops to address ongoing issues. In addition, one person must be identified to lead the process, to allocate responsibilities within the project team and to track the evidence throughout the project. In order to do this, fees need to be set aside, whether employing a separate environmental consultant or a Green Star professional within the architect’s organization.

Other consultants also need to build allowances into their fee agreements to cover the costs of the production of documentary evidence for Green Star certification.

Green Star’s American cousin LEED has been criticized for being overly rigorous, inconsistent, costly and time-consuming.1 While many of these criticisms can also be applied to Green Star, particularly in the compliance context to which it has been transferred, it is likely that ongoing feedback will help to iron out the process. The rapid adoption of Green Star demonstrates its relevance to the commercial building industry. However, until it becomes mainstream practice, it is important that all members of the project team enter the field with their eyes wide open.



1. Green Building Alliance, “LEED-NC – The First Five Years: Report on the Greater Pittsburgh region’s experience using Leadership in Energy & Environmental Design for New Construction.” Online at http://www. veyReport_Final.pdf (Accessed 28 September 2006).


Green Building Council and Green Star Developed by the Green Building Council of Australia, this is the outcome of several other assessment methods, including LEED, BREEAM and the Melbourne Docklands ESD Guide.

Rating tools, and technical manuals can be downloaded from the website, as well as information on project certification. Case studies of certified projects, industry news, training and accreditation programmes, and policy statements are also included.

T 02 8252 8222 E W Australian Environmental Labelling Association and the Good Environmental Choice LabelWebsite details the background and standards around the Good Environmental Choice label, including access to specific standards, information on the development of standards and application processes. The site also links to the Green Procurement Database and the Certified Product Register.T 02 6287 3100 F 02 6287 3800 E W BREEAMDeveloped by the United Kingdom’s Building Research Establishement, along with industry partners. This ESD design assessment tool, covers the environmental performance of both new and existing buildings.E W LEEDLeadership in Energy and Environmental Design (LEED) Green Building Rating System. DEveloped in the United States through the international Green Building Challenge.W DSE ESDC GuidelinesEnvironmentally Sustainable Design and Contruction Principles and Guidelines for Capital Works Projects. Developed by the Victorian Government’s Department of Sustainability.W NABERSNational Australian Built Environment Rating System.

A performance-based rating system for existing buildings developed by the Australian Greenhouse Office, which is still in a draft form.

W BASIXThe New South Wales Government’s Building Sustainabilty Index (residential only).W VICBESTDeveloped by Connell Wagner for the Victorian Government.STEPSDeveloped by the Moreland and Port Phillip Councils.W www.morelandsteps.

Melbourne Docklands ESD GuideThe VicUrban ESD design Assessment tool.W docklands/about/design/esd.




Published online: 1 Nov 2006


Architecture Australia, November 2006

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