BASIX Multi Units


There are several additional areas in a BASIX multi unit assessment compared to a single dwelling development. In a multi unit development you need to address common areas and central systems of the development for all the indices and you need to provide different specifications for the development. You also have only one option for thermal comfort evaluation in a BASIX multi unit development assessment. If you are assessing more than one dwelling for BASIX compliance regardless of the type and specifications of the dwellings you must select more than one dwelling in the online assessment tool.
You can get a BASIX for multi unit developments for any number of single detached or attached dwellings, any number of unit buildings with any number of units in each or, in general, any combination of these types in a single BASIX certificate. Since 1st July 2011 a fee must be paid for issuing a certificate which is calculated based on the number and types of dwellings in a development. A table is provided for current fees in effect in BASIX Certificate Cost page.
If your development has more than 100 units you must contact the NSW department of planning to arrange for a special data entry case since the online assessment tool only accepts less than 100 units in each development. You can also divide the development into several sections each with less than 100 units for ease of data entry and also for calculation time since the BASIX online tool becomes very slow for large number of units. The other reason that you might consider dividing a project into sub projects in due to the restrictions in the online tool for building systems like the number of lifts which is restricted to 10. Data entry for a BASIX multi unit development is performed in 5 separate sections and all sections must be fully filled with correct type of data before the BASIX multi unit assessment can be performed and a certificate is generated. These sections are as follow:

  • Address & Type: You enter project address and building types like number of single detached or attached dwellings and number of unit buildings.
  • Details: Data related to site specifications, common areas, central systems, unit building and each dwelling specifications are entered in this section.
  • Water: Water consumption and efficiency measures for common areas and each dwelling is requested.
  • Thermal Comfort: Simulation method is the only allowed method for multi units and BASIX thermal comfort protocol must be followed in performing the simulation.
  • Energy: Energy consumption and efficiency data of the project is entered in this section like lighting, HVAC, appliance, alternative energy, etc for central systems, common areas and each dwelling.

In the Summary section you can get useful hints to improve the sustainability performance of your building if you fail to meet the requirements of BASIX and address the missing data entry elements. The Certificate section will allow you to print Draft report as well as a formal certificate if you have filled all the required fields and passed the BASIX scores for your multi unit development.
If you have utilized an unusual technology for energy or water efficiency in your development which cannot be addressed by regular BASIX assessment processes for multi unit developments you are able to apply for a BASIX Alternative Assessment under the Certificate section of the BASIX online tool. Any of the the following criteria qualifies a building to follow the path of a BASIX Alternative Assessment:

  • If the building is of a type which cannot be characterized by the interactive online assessment tool.
  • Water and energy efficiency measures and technologies in the building are not being addressed in the BASIX online tool.
  • If the building is of heritage significance and BASIX requirements are in conflict with heritage nature and characteristics of building.

Developments which are planning to be assessed under the BASIX Alternative Assessment method will still be required to meet the sustainability targets for water and energy efficiency and thermal comfort and this approach is only for technologies not currently addressed in the assessment tool.