- Owners and Builders
The National Construction Code (NCC), maintained and published by the Australian Building Codes Board (ABCB), details the minimum necessary requirements for safety, health, amenity and sustainability in the design and construction of new buildings throughout Australia. The NCC is given legal effect by relevant legislation in each state and territory.
Software tools accredited under NatHERS are referenced in the NCC as part of one option for demonstrating compliance with the relevant energy efficiency Performance Requirements for houses (Class 1 Buildings) and individual units in apartments (Class 2 buildings). This reference means that the NatHERS Administrator and the ABCB work together to ensure that software tools accredited under NatHERS continue to remain suitable for meeting energy efficiency requirements in the NCC.
Note that in addition to some General Requirements, the Performance Requirements are the only mandatory parts of the NCC.
At present, there are three options to meet the building thermal Performance Requirement for Class 1 buildings.
The two methods predominantly used are known as Deemed to Satisfy (DTS) options. Under these DTS options, a home is considered to meet the Performance requirements of the NCC if they meet specific criteria. These include:
Obtaining an energy rating of at least 6 stars using a software tool accredited under NatHERS, coupled with complying with certain provisions for energy-saving features, and provisions for building sealing.
The Housing Industry Association estimates that 71 % of new residential buildings (Class 1 and units within a Class 2) use this option as the means of demonstrating compliance with the Code.
Complying with the relevant DTS elemental provisions detailed in the NCC (which prescribe specific levels of energy efficiency materials be included in the home, such as insulation and glazing).
There is also a third option for practitioners to develop a:
Performance Solution, where it can be demonstrated that the proposed solution meets the Performance Requirement through other means.
For example, a Performance Solution could demonstrate that the heating and cooling loads of the proposed building are less than or equal to the heating and cooling loads of a reference building, as prescribed in the NCC (V18.104.22.168).
The most common option used to meet the relevant energy efficiency Performance Requirement for units in a Class 2 building apartment building, is to obtain an energy rating of at least 5 stars for each unit and an average of 6 stars across all units in the building using a software tool accredited under NatHERS. Certain provisions for energy-saving features and detailed provisions for building sealing must also be met.
Unlike Class 1 buildings, there are no DTS elemental provisions for units in a Class 2 building. However, similar to Class 1 buildings, there is the option for practitioners to develop a Performance Solution to meet the Performance Requirement. For the remainder of the apartment building, such as common areas, practitioners can use the DTS elemental provisions or develop a Performance Solution.
Each of these pathways is detailed in the NCC.
 Where the building is in NCC climate zones 1 or 2, a rating of 5 or 5.5 stars may be allowed if the building has an outdoor living area meeting certain requirements for the insulation of the roof of the outdoor area, and the installation of a ceiling fan.
The NCC is given legal effect by relevant legislation in each state and territory, which essentially ‘call-up’ the NCC to fulfill certain technical requirements for new buildings and new building work, such as alterations or additions. More information is available from state or territory building regulators.
In New South Wales, the online Building Sustainability Index (BASIX) system replaces the NCC energy efficiency requirements and adds other aspects of sustainable development. BASIX accepts NatHERS software results as one way of meeting its separate targets for the heating and cooling performance of the building.