Explainer: Green Star and NABERS Ratings

As the base building energy efficiency of office buildings improves, through better management, many building and business owners are turning their attention to ways for office tenants to save even more energy. Tenancies typically consume approximately 50 per cent of the energy used within the building.

Currently two voluntary national accreditation programs exist to measure and report on environmental performance of office tenancies and assist in guiding best practice office fitouts.

  • Green Star assesses the design of your office fitout
  • NABERS measures its ongoing operational energy efficiency

Green Star rating for office tenants

The Green Building Council of Australia’s Green Star - Interiors rating tool is one way of designing an energy efficient office fitout that, if managed correctly, will ensure that office tenancies do not waste energy in operation and organisations are not paying more than they need to on their energy bills.

The Green Star - Interiors rating tool has been designed to help office tenants and interior designers of office fitouts to create high-performing, best practice and sustainable fitouts. Covering a broad range of categories, the Green Star - Interiors rating tool addresses energy efficiency through assigning credits points based on the implementation of energy efficient lighting and equipment as well as a design that not only consumes less power but also allows occupants to better monitor and manage their energy consumption.  Some examples of these initiatives include:

  • High efficiency lighting with controls
  • Lighting zoning
  • Lighting sensors (movement or daylight)
  • Sub-metering to monitor consumption
  • High efficiency equipment including computers, laptops, printers, fridges, dishwashers and televisions
  • High efficiency supplementary heating, cooling and hot water
  • Allowing more daylight penetration to reduce the need for electric lighting during the day
  • Installation of blinds and awnings to reduce heat load and glare.

Employing these initiatives sets an office up for ongoing operational cost savings as long as they are managed effectively.  This includes ensuring lighting, controls and equipment are all commissioned properly after installation and that energy consumption is closely monitored via the sub-metering system on a frequent basis to ensure that it doesn’t start to creep up. Delegating a person or a green team to take charge of monitoring and evaluation of energy consumption and to provide reporting and recommendations on a frequent basis can assist with this.  

The benefits of a high performing, energy efficient fitout are many and include both direct financial and indirect financial benefits such as:

  • Reduced energy bills and carbon footprint
  • A reduction in staff turnover by retaining employees
  • Attraction of high quality employees
  • Improved employee wellbeing and productivity and a potential reduction in OH&S liabilities
  • Demonstrating to your staff that you are committed to reducing the impact of your office on the environment
  • Promoting environmental leadership to your customers and other stakeholders, improving branding and corporate image.

Whilst some SME tenancies may not want to undertake a full Green Star - Interiors rating, the energy efficient elements within the tool can still be used to assist in designing a new tenancy or upgrading an existing one. Many of these energy efficient elements can be implemented with minimal cost. A building’s facility manager may be able to help guide the process or where an architect or interior designer has been engaged it should be requested that the fitout is designed to Green Star – Interiors’ principles.  

NABERS ratings for office tenants

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 - well below average and has a lot of scope for improvement.
  • A 6 star rating indicates a market leading performance.
  • A 6 star rated tenancy will have half the greenhouse gas emissions of a one with 5 stars.

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 fitout, whilst NABERS measures its ongoing operational energy efficiency.


CitySwitch and ratings schemes

CitySwitch Green Office is a free program designed to help office tenants better understand, manage and reduce their energy consumption. Signing up to the program involves a commitment to achieving and maintaining a 4-6 Star NABERS rating for your office. Signatories benefit from access to a local program manager, free guidance and resources, a peer network of leading business and a way to get recognised for their efforts.

How to get involved in CitySwitch

How to get a benchmark NABERS rating 

Free resources on Energy Action Planning

Free resources on Behaviour Change

The CitySwitch program is an effective way for organisations to gain free, independent advice and support to improve the energy efficiency and sustainability of their office on an ongoing basis.


Case Study: WT Sustainability

This inspirational case study from CitySwitch Signatory WT Sustainability demonstrates how the Green Star and NABERS tools were used to achieve a 6 Star NABERS Energy tenancy rating and an energy consumption level of 78 per cent less than a typical office.

This Activity received funding from the Department of Industry as part of the Energy Efficiency Information Grants Program. The views expressed herein are not necessarily the views of the Commonwealth of Australia, and the Commonwealth does not accept responsibility for any information or advice contained herein.


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Explainer: Green Star and NABERS Ratings

How are Green Star, NABERS used in office tenancies? Currently these two voluntary national accreditation programs exist to measure and report on environmental performance of office tenancies and assist in guiding best practice office fit-outs, and they can be complementary.

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