Compliance with BASIX - certifier's role

BPB information sheet September 2011

Note to readers: information sheets relate to the legislation in force at the time, which may since have been amended.

BASIX is an online sustainability tool that mandates water and energy savings for residential developments in NSW. It satisfies an objective of the Environmental Planning and Assessment Act 1979 for development to be ecologically sustainable by ensuring homes are designed to use less potable water and be responsible for fewer greenhouse gas emissions by setting energy and water reduction targets for houses and units.

This information sheet out lines requirements certifying authorities have when a BASIX certificate is required, when a BASIX certificate needs to be modified or when authorities need to check and notify that all relevant BASIX commitments have been met.

For more background on BASIX and how it works, visit

Development application (DA) or complying development certificate (CDC) stage

BASIX affected development is defined in clause 3 of the Environmental Planning and Assessment Regulation 2000. It applies to all new dwellings in NSW, renovations where the work is valued at $50,000 or more, or where a swimming pool (or pool or spa) of 40,000 litres or more is being installed. BASIX is optional for renovations under this value or for smaller pools and spas.

Prior to submitting a DA or CDC application, the owner, builder or architect must complete a BASIX assessment online. Access is available free to any registered user. A fee, prescribed by the EP&A Regulation, applies for the issue of the completed certificate. The online tool assesses a house or unit design and compares it against energy and water reduction targets for that region or climate. The user needs to make appropriate selections - for example in insulation, hot water systems, or fittings - that combine to meet the targets (prescriptive requirements, rather than targets, apply to alterations and additions).

Once targets are met, a BASIX certificate c an be obtained. The certificate lists the commitments made by the applicant to build the project described in the certificate, listing specific measures for design, water and energy features. The BASIX certificate also identifies when these measures need to be demonstrated and checked (whether on DA plans, Construction Certificate (CC) plans, CDC plans and/or by a certifying authority’s inspection).

The need to fulfil commitments on the BASIX certificate becomes a prescribed condition of any development consent and applies regardless of whether nominated as part of council’s conditions of consent. For a CDC, the EP&A Regulation requires the certificate to be issued subject to a condition that the BASIX commitments be fulfilled. This means the commitments must be complied with and checked just like any other conditions of consent.

The BASIX certificate must correspond with the DA or CDC drawings and must be checked by the consent authority at approval stage and by the certifying authority during construction. At DA or CDC stage, only commitments marked in the DA or CDC column of the certificate need to be checked. This includes aspects such as window size or rainwater tank size that normally need to be confirmed as part of the approval process.

These features should be depicted on the drawings or, if not practical, on the plans as text. While the commonplace method of using tables on drawings to describe the BASIX commitments is handy for consent authorities and certifiers to check, these should not be the only method of indicating the larger scale commitments.

For example, rainwater tanks should be drawn to scale or pergolas should be incorporated in to the design and not simply a note in a table.

If the simulation method is used to comply with the Thermal Comfort Index, the BASIX Certificate will require an Assessor Certificate, issued by an accredited assessor, to be attached to the DA or CDC application.

An applicant can lodge a revised BASIX certificate with the consent authority if they wish to alter their BASIX commitments before their application is determined. Revised certificates should show the same certificate number as the parent, with a suffix of to clarify the version (for example, '_02', '_03'). No additional BASIX fee applies to revise a certificate that relates to the same development lodged for assessment or under construction.

Other amendments to the building design not directly related to BASIX commitments may also occur during the approval or construction stage. If the amendment results in the proposed development differing materially from the description contained in the existing BASIX certificate, the applicant needs to lodge a revised BASIX certificate. While the consent authority will determine the extent of this difference, it should be noted that even changes to window sizes, building floor area or roof construction may impact the thermal comfort and energy score of the dwelling.

If the current BASIX certificate remains consistent with t he development (as amended) no additional certificate is required.

Construction certificate (CC) stage

Where a DA requires a BASIX certificate, the application for a CC must also be accompanied by a BASIX certificate.

BASIX commitments marked in the CC column of the BASIX certificate must be shown on all accompanying plans and specifications. The CC must be consistent with the approved DA.

As at the DA stage, drawings, as well as commitments indicated in tables, should also be used to show those commitments that have an impact on the design and construction. For example, solar hot water systems must be to scale and have a specific location on the roof. Drawings will also show integration of BASIX with other aspects of the design to avoid issues during construction.

Details such as heating system type and efficiency can be included in a table rather than nominated on drawings. Typically any commitment that is part of the design should be on the drawings.

Certifying authorities should also ensure the relevant technical standards in the energy efficiency sections of the Building Code of Australia (BCA) that apply in NSW will be met by the design before issuing a CC or CDC.

The applicant can change some commitments on their BASIX certificate after the CC has been issued, provided those aspects have not yet been constructed or installed. If major changes are proposed and a s96 modification to the DA is required, a new BASIX certificate is required to reflect those changes.

During construction

During construction, the certifying authority should be aware of the commitments listed in the BASIX certificate when conducting critical stage inspections. Some BASIX commitments (such as insulation) will be easier to check at this stage, rather than when the dwelling is built and ready for an occupation certificate.

Occupation certification (OC) stage

The principal certifying authority (PCA) cannot issue the OC until all relevant commitments in the BASIX certificate (as marked in the certifier check column) are certified. This includes features like showerheads, insulation, rainwater tanks and hot water systems. Items that do not impact on health and safety, such as the area of landscaping or type of oven or cook top that aren’t marked in the certifier check column may not need to be certified prior to the issuing of the OC. However, these commitments still remain conditions of consent and can be enforced after the OC is issued.

The PCA can take advice from other professionals to confirm commitments are satisfied. Building professionals should be provided with a copy of the relevant part of the BASIX certificate so they can confirm that their work meets that certificate.

It is common for suppliers to provide invoices, receipts and other documentation as evidence that commitments have been met. Some window manufacturers produce certificates that summarises the U-value and Solar Heat Gain Coefficient (SHGC). The PCA may also request a Part 4A Compliance Certificate in certain circumstances.

For large multi-unit developments, commitments may be grouped according to subcontractors or installers, with those subcontractors providing documentation for a number of commitments on the BASIX certificate.

Completion receipts

BASIX completion receipts let the Department of Planning, Industry and Environment know when a BASIX affected building has been constructed and occupied. The receipts help determine the extent to which BASIX is delivering on forecast energy and water savings.

Prior to the issue of an OC the PCA must access the BASIX online administration tool and enter the BASIX certificate number, postcode and date of final inspection to complete a receipt. This component of the tool is only available to private ac credited certifiers and councils and requires a unique username and password. Most councils and certifiers have been provided access. Certifiers and councils should contact the BASIX helpline at if they do not have an administration account and need to access BASIX completion receipts.