Before lodging a Development Application or Complying Development Certificate in NSW, it is worth checking that the BASIX Certificate matches the plans, specifications and project details being submitted. BASIX is not just a form to attach at the end. It records the water, energy and thermal performance commitments that need to follow the project through approval, construction and final certification.
NSW Planning explains that once a BASIX assessment is completed and the standards are met, the BASIX Certificate must be generated and submitted with the development application or complying development certificate. The certificate lists the key elements of the design, known as sustainability commitments. NSW Planning Portal
Before lodging your DA or CDC, check that the BASIX Certificate matches the current plans and includes the correct project type, dwelling details, glazing, insulation, water systems, energy systems, rainwater tanks, solar panels, pools, spas and other commitments. If the certificate does not match the plans, fix the issue before lodgement.
The first step is to confirm whether the project is being lodged as a Development Application or Complying Development Certificate. BASIX can be required for both pathways, but the documentation timing and certifier expectations may differ. The certificate should be prepared for the correct project and lodged with the correct application type.
If the project changes from CDC to DA, or from DA to CDC, it is worth checking whether the BASIX Certificate still matches the application pathway, project details and documentation set.
BASIX project type selection affects the assessment. A new single dwelling, secondary dwelling, alteration and addition, dual occupancy, townhouse development, apartment building, pool, spa or mixed use project may need different information. Selecting the wrong project type can lead to missing inputs, incorrect assumptions or a certificate that does not match the approval documents.
Before lodgement, check that the BASIX Certificate reflects the actual project type shown on the plans. This is especially important for granny flats, dual occupancies, townhouses, apartments, mixed use developments and alterations to existing homes.
The BASIX Certificate should match the project address and site details used in the DA or CDC documentation. This includes the address, lot details and any other project identifiers relevant to the lodgement. Even a simple address mismatch can create confusion during submission or later certification.
For larger projects, also check that the number of dwellings, buildings, storeys, apartment types or dwelling types matches the plans and application information.
Timing matters. NSW Planning states that a BASIX Certificate is valid for 3 months prior to submission to council or an accredited certifier. If it is not lodged within 3 months, a new certificate must be generated and additional fees may apply. NSW Planning Portal
Before lodgement, check the certificate date. If the project has been delayed, do not assume the BASIX Certificate is still usable. If a new certificate is needed, also check whether the plans have changed since the original assessment.
The BASIX Certificate should be based on the current drawing set, not an outdated version. If the plans have changed since the assessment was completed, the certificate may no longer match the project. This can create issues before lodgement, at construction certificate stage or during final occupation certificate checks.
Before lodging, compare the BASIX Certificate against the latest site plan, floor plans, elevations, sections, roof plan, window schedule and specifications. If anything significant has changed, ask for a BASIX review before submitting.
BASIX inputs should reflect the actual dwelling layout and project scale. Check that the certificate aligns with the number of dwellings, dwelling types, apartment types, floor areas and room layouts shown in the plans. This is especially important in dual occupancy, townhouse, apartment and mixed use projects.
If a room layout, floor area, ceiling height, storey count or dwelling type has changed, the BASIX outcome may need to be checked before lodgement.
Glazing is one of the most common causes of BASIX and NatHERS rework. Before lodging, check that the window sizes, locations, orientations, frame types, glass types, U values, SHGC values and shading assumptions match the plans and window schedule.
Pay particular attention to large windows, west-facing glazing, skylights, glazed doors and any window schedule changes made after the initial assessment. If the BASIX Certificate includes glazing performance values, those values need to be practical for procurement and consistent with the documentation.
Insulation and construction details should match the BASIX Certificate and any NatHERS assessment. Check wall, roof, ceiling and floor construction, insulation R values, roof colour, raked ceilings, suspended floors and slab insulation where relevant.
If the BASIX Certificate relies on a particular insulation value or construction system, it should be reflected in the plans, sections, specifications or construction notes. Generic notes can cause problems if they conflict with the assessment assumptions.
Water and energy systems can affect the BASIX outcome. Before lodging, check that the hot water system, heating system, cooling system and ventilation assumptions match the intended design. If the project is all electric, gas connected, using heat pump hot water or relying on central services, those choices should be clear.
If the system type has not been selected yet, the BASIX Certificate may include a commitment that the builder or client later needs to follow. Make sure the commitment is realistic before lodgement.
If the BASIX Certificate includes a rainwater tank, check the tank capacity, location, connected roof catchment and connected uses. The tank should fit on the site and be shown clearly enough for approval and later construction documentation.
Also check water efficient fixtures, garden irrigation, pool or spa top-up and any central water system commitments. If a water commitment is not realistic or not shown on the plans, it can create problems later.
If solar PV is included in the BASIX Certificate, check that the nominated system size is practical for the roof or site. The roof plan should have enough suitable, unshaded space, and the solar commitment should not conflict with skylights, plant equipment, roof form or overshadowing.
If batteries or other alternative energy systems are included, check that the commitment is clearly understood. Solar can help BASIX energy performance, but only if the system can actually be installed as committed.
If the project includes a pool or spa, check whether it has been included correctly in BASIX. Pools and spas of 40,000 litres or more can trigger BASIX requirements. Pool and spa commitments may include volume, cover, heating, pump system, timer, shading and rainwater top-up details.
If the pool design changes after BASIX is issued, the certificate should be reviewed before lodgement. Pool volume, heating, pump and top-up assumptions can affect the certificate.
If you already have architectural plans, complete the BASIX checklist so Certified Energy can review the site, design and construction information needed for your certificate.
Complete BASIX Checklist