Sustainability Assessment tools – comparison
The type of building to be assessed determines the potential tools available for assessing that building. It is not always practical or possible to achieve an assessable 5 or 6 star rating for some buildings. The most common rating tools can be reviewed briefly as follows:
1. Residential energy ratings – NatHERS (Nationwide House Energy Rating Scheme) rating
This is the commonly known 6 star energy efficiency rating for residential dwellings. The rating assessment can be undertaken using any of the FirstRate5, Accurate or BERS rating tools. Ratings from 1 – 10 stars are available for a dwelling, with the National Construction Code – Building Code of Australia (NCC-BCA) requiring a mandatory minimum 6 stars (for a class 1 dwelling) or a 6 star average (with a minimum on any apartment of 5 stars) for class 2 apartment developments. A HERS rating or a Part 3.12 Building Code deemed to satisfy assessment is mandatory for all new class 1 & class 2 buildings and extensions and is only available to residential houses and multi unit developments. HERS ratings are undertaken on the design of these buildings. Commercial buildings of class 3-10 cannot be rated using any of the three tools, and cannot obtain a HERS rating. BCA Section J assessments are required for such buildings.
2. Sustainable Design Assessments for the Planning Process
These assessments require a Sustainable Design Assessment or Sustainability Management Plan depending on the size of a development. These assessments both generally use the BESS tool and other tools to assess Water Sensitive Urban Design (WSUD) performance. Approximately two thirds of Victorian Councils are now implementing the Sustainable Design Assessments as a mandatory requirement in their planning permit process.
3. Green Star rating
Green Star rating tools provides either a 4 star, 5 star or 6 star rating. Green Star is generally voluntary and can be used to assess most types of buildings. Four Green Star tools exist: Design and As Built, Communities, Green Star Interiors and Green Star Performance. Green Star – Design & As Built is currently the most commonly discussed Green Star tool, which assesses the sustainability attributes of a building through nine categories:
- Indoor Environment Quality (incl daylight, natural ventilation, indoor air quality-VOCs, acoustics etc);
- Land Use and Ecology;
- Emissions; and
The GS Design and As Built tool replaces a suite of older similar tools that were building type specific, and which are now being phased out ie GS Multi-Dwelling, Office, Education etc.
GS is a relatively expensive process – lots of documentation to show compliance
A 4 star Green Star building represents a building in the top 25% of buildings nationally in terms of its sustainable design. A 5 star Green Star building represents a national best practice building. A 6 star Green Star building represents a worlds best practice green building. Obtaining a Green Star rating is a voluntary accreditation. The process of achieving a Green Star rating is usually integral with the design of a building, and requires a lot of design consideration, time and document substantiation. It is not an in-expensive process and would practically mainly only be considered for projects above $3M in value or where the client has a very strong commitment to achieving a very high standard of sustainable design in their building.
4. BCA Section J compliance
Compliance with Section J of the Building Code of Australia is mandatory for all commercial buildings. These assessments must be completed for a commercial building to obtain a building permit. There is no star rating applied with these assessments, however a report is required to be completed to confirm compliance in energy efficiency areas.
5. NABERS (National Australian Built Environment Rating System) rating
NABERS unlike the above two rating tools is a performance based rating system for completed / existing buildings that relies on 12 months of operational data before a rating can be determined. NABERS assessments can be completed on the following building types: offices, homes, hotels, retail, schools, hospitals, and transport. NABERS ratings range from 1 – Poor performer 2 – Below average performer 3 – Above average performer 4 – Strong performer 5 – Top performer 6 – Best practice.
6. Building Energy Efficiency Certificate (BEEC)
Commercial building mandatory disclosure – under the national Commercial Building Disclosure program the owners of all commercial buildings over 1000m2 are required to undertake and disclose the results of a BEEC to prospective tenants or building buyers. The BEEC involves 3 components: a NABERS base building energy efficiency rating, a tenancy lighting assessment, and behavioural energy efficiency guidance. NABERS energy ratings which assess the infrastructure of the building, must not take into account Green Power. A BEEC is valid for 12 months. For further information on the mandatory Commercial Building Disclosure program refer to www.cbd.gov.au