What is Green Star?
The Green Building Council of Australia (GBCA) has developed a ‘Green Star Rating Tool’ to evaluate the environmental performance of Australian commercial buildings based on a wide range of criteria including;
- sustainable sites: encouraging the utilisation of brown field sites with existing transport links
- longevity: designing facilities for an extended life by ensuring the space is flexible to maximise options for future use
- energy efficiency: reducing energy consumption and encouraging the use of renewable energy
- water efficiency: reducing water consumption through better design, harvesting rain water, recycling grey water and treatment of black water
- material, resource and material conservation: reduction in embodied energy, design for recycling and reuse
- indoor environment quality, including air quality, lighting levels, thermal comfort and ventilation rates.
Green Star is a comprehensive, national, voluntary environmental rating system that evaluates the environmental design and construction of buildings and communities. Best practice is 4 star. Australian excellence is 5 star. International leadership is 6 star.
The green star categories are:
- Building input: Evaluate based on a 50 year horizon
- Management: Credits address the adoption of sustainable development principles from project conception through design, construction, commissioning, tuning and operation.
- Indoor Environment Quality: Credits target environmental impact along with occupant wellbeing and performance by addressing the HVAC system, lighting, occupant comfort and pollutants.
- Energy: Credits target reduction of greenhouse emissions from building operation by addressing energy demand reduction, use efficiency, and generation from alternative sources.
- Transport: Credits reward the reduction of demand for individual cars by both discouraging car commuting and encouraging use of alternative transportation.
- Water: Credits address reduction of potable water through efficient design of building services, water reuse and substitution with other water sources (specifically rainwater).
- Materials: Credits target resource consumption through material selection, reuse initiatives and efficient management practices.
- Land Use & Ecology: Credits address a project’s impact on its immediate ecosystem, by discouraging degradation and encouraging restoration of flora and fauna.
- Emissions: Credits address point source pollution from buildings & building services to the atmosphere, watercourse, and local ecosystems.
- Innovation: Green Star seeks to reward marketplace innovation that fosters the industry’s transition to sustainable building.
The Green Building Council of Australia has certified more than 600 buildings around Australia.With more than 7.2 million square metres of Green Star-certified space around Australia, and a further 8 million square metres of Green Star-registered space, Green Star is transforming Australia’s built environment. Green Star-rated buildings produce around a third of the emissions and use about a third of the electricity compared to the average Australian building, according to a report by the Green Building Council of Australia.
Green Star Toolkit
- Design and As Built: Guiding sustainable design and construction across a range of shools, offices, industrial facilities, public buildings, retail centres and hospitals (4 to 6 star)
- Interiors: Transforming the interior fitouts (4 to 6 star)
- Communities: Improving the sustainability of projects at the neighbourhood, precinct or community scale (4 star to 6 star)
- Performance: Supporting higher levels of operational efficiency within existing buildings (4 to 6 star)
National Australian Built Environment Rating System (NABERS)
The National Australian Built Environment Rating System (NABERS), is a government initiative to measure and compare the environmental performance of Australian buildings and tenancies. There are NABERS rating tools for commercial office building to measure greenhouse gas emissions, energy efficiency, water efficiency, waste efficiency and indoor environment quality. There are also energy/greenhouse and water rating tools for hotels, shopping centres and data centres.
The National Australian Built Environment Rating System known as NABERS, is a national environmental rating system which measures the operational efficiency of a building or tenancy in regards to its energy and water consumption, waste management and indoor environment quality.
Information including utility bills is used to measure environmental performance and a star rating is applied.
- The scale is from 1 to 6 stars.
- 1 Star rating means the building or tenancy is performing poorly
- 6 star rating indicates a market leading performance and tenancy will have half the greenhouse gas emissions of a 5 star.
The NABERS tool is a great way to ensure that your energy efficient fitout delivers real results. A green fitout is not a guarantee that you will be green in operation – an office tenancy is not a static entity. Lights and equipment can be left on more than they are needed and unless there is someone appointed to constantly monitor energy consumption, these issues can go unnoticed, leading to your energy consumption increasing over time.
Tenancies can use the NABERS self-assessment tool to get an idea of how the tenancy is performing. However, only an accredited rating provided by an accredited NABERS assessor can be reported or promoted. Accredited ratings are required to comply with Commercial Building Disclosure and CitySwitch. It is recommended that NABERS be used to benchmark performance every year to ensure that your tenancy is performing as it should and meaningful targets are set.
NABERS can be seen as complementary to Green Star as Green Star assesses the design of your office fit-out, whilst NABERS measures its ongoing operational energy efficiency.
Comparison of Green Star and NABERS
Predicted vs. Actual Performance of Green Buildings
Research show that there is a difference between the actual energy use compared to predicted use. To help develop the knowledge and technology to deliver (Commercial) Zero Energy Buildings by 2025, research against predicted verses actual energy (cost, benefits and outcomes) use of buildings showed that more energy was used than predicted. Some of the reasons given for this disparity were:
- controls and energy saving systems not working together properly
- daylighting strategies didn’t deliver expected energy savings
- installed insulation was less effective than the modelled insulation
- appliance and other plug loads were higher than expected
- the occupants didn’t use the building and energy saving equipment as predicted
Buildings that set the most aggressive energy targets delivered the best results. Recommendations included:
- Energy use monitoring and feedback to the building operators is essential to ensure than design energy use goals are
achieved and measured
- Users and operators of a building must be involved in its design. This will reduce the incidence of faulty operating assumptions and help ensure the building is operated the way it was designed to. A building’s systems also need to be made as simple and robust as possible, to ensure its ease of operation and maintenance.
- Building owners and operators need better incentives – such as time-limited certification – to maintain and operate their building to its performance goals. Further, it should be a precondition of certification that a building’s predictedand actual energy performance are compared through detailed building monitoring.
- It is vital that the sustainability rating tools continue to be developed and refined, particularly in the area of energy use. Real performance information, together with the reasons for any deviation, must be given to the building owner, operator, designers and relevant green building rating organisation.
- Design-focused rating tools should be better aligned with the actual energy-use rating tools, such as Energy Star and NABERS Energy.
Following these steps, we can begin to close the gap between the predicted and actual energy performance of green buildings. Without them, fresh charges of greenwashing by the building sector are bound to emerge.
Source: Green star-rated buildings outperform, Green Star website, NABERS website