What This Requirement Covers
These requirements set out the National Construction Code (NCC) and related Housing Provisions expectations for integrating solar photovoltaic (PV) systems, battery storage and provisions for renewable energy in new homes in Australia. They are intended to ensure new dwellings are designed and constructed to reasonably accommodate on-site renewable generation, to support energy efficiency and decarbonisation goals, and to maintain the safety and structural integrity of buildings when PV and associated equipment are installed.
The rules apply to new residential buildings (primarily Class 1 houses and Class 10 ancillary structures where PV is attached) and also inform provisions for multi-residential buildings (Class 2) and other building classes where rooftop PV, batteries or electric vehicle charging infrastructure are incorporated. The requirements address reserved roof area for PV, electrical and fire-safety interactions, structural and wind-loading considerations, and the need to follow relevant Australian Standards and state schedules.
Key Requirements
- Reserved roof area for PV: For applicable new buildings the NCC requires that at least 20% of the roof area be left clear and available for the installation of solar photovoltaic panels, unless the building already has PV installed on at least 20% of the roof area or equivalent generation capacity is provided elsewhere on site, or where 100% of the roof area is shaded for more than 70% of daylight hours. (See: NCC Volume One, J9D5 and J9D4.)
- Battery-ready provisions: Where required by the NCC, electrical switchboards and distribution infrastructure must be sized and located to accommodate a battery system and to permit future connection of PV systems rated to produce maximum electrical output on at least 20% of the roof area. (See: NCC Volume One, J9D5.)
- Electric vehicle (EV) charging provisions: For buildings providing car parking, the NCC sets minimum numbers of EV-ready spaces per storey dependent on total carpark spaces (for example: 1 for 10-24 spaces, 2 for 25-48 spaces, scaling upward) to ensure electrical distribution provision for EV charging. (See: NCC Volume One, J9D4.)
- Energy efficiency interaction: Renewable generation is treated as a credit against regulated energy in the ABCB Housing Provisions. The Housing Provisions define renewable energy and regulated energy and set out how on-site generation reduces a building’s regulated energy demand. (See: ABCB Housing Provisions Standard 2022, Definitions and Part 13.)
- Structural and wind loading: PV arrays and mounting systems must be designed to the same structural performance expectations as other roof-mounted equipment. Design should follow the relevant parts of AS/NZS 1170.2 for wind actions, and other structural standards as applicable (for example AS 4100 for steelwork connections where used). Exact mounting and framing details should comply with manufacturer instructions and referenced standards. (Refer to AS/NZS 1170.2 and relevant product certification requirements.)
- Electrical installation and safety standards: PV and battery systems must be installed in accordance with the applicable electrical and PV standards, including AS/NZS 5033 (installation of photovoltaic arrays) and AS 4777.1 (grid connection of energy systems), and compliance with state electrical licensing and wiring rules (AS/NZS 3000). Specific inverter, isolation and earthing details follow these standards.
- Fire and emergency access: Installations must not adversely affect required fire separation, combustibility requirements or egress provisions. Fire authority guidance and NCC clauses related to egress and fire safety should be checked where PV and battery systems are mounted near fire-isolated elements. (See ABCB Housing Provisions Part 13 and NCC Volume One governing requirements where fire-safety interactions are relevant.)
- Referenced NCC and Housing Provisions: Key references include NCC Volume One, J9D4 and J9D5 (requirements reserving roof area and related provisions for PV, batteries and EV infrastructure) and the ABCB Housing Provisions Standard 2022, Part 13 (energy efficiency, definitions and application). Use these exact clause references when confirming compliance with certifiers.
- Australian Standards: Commonly referenced standards for PV and related works include AS/NZS 5033 (installation of PV arrays), AS 4777.1 (grid connection), AS/NZS 3000 (wiring rules), AS/NZS 1170.2 (wind actions), plus material/structural standards such as AS 4100 and AS 3700 where structural steel or masonry connections are used. Always cite the specific clause within these standards in detailed designs.
Residential vs Commercial
- Residential (Class 1 / Class 10): The NCC and ABCB Housing Provisions explicitly target dwellings through Part 13. For typical detached houses (Class 1a) the 20% roof area reservation, battery-ready provisions and energy accounting in the Housing Provisions are directly applicable. Installation responsibilities fall to the builder and licensed solar/electrical contractors who must follow AS/NZS 5033 and AS/NZS 3000.
- Multi-residential and Commercial (Class 2-9): For Class 2 apartment buildings and commercial buildings the NCC Volume One provisions apply. The same 20% roof area rule is referenced for buildings where the Volume One provisions apply (see J9D4 and J9D5). However, larger or non-residential buildings may face additional requirements for electrical distribution, fire engineering, structural design, and tenancy metering; they may also be subject to specific state or local planning conditions. For commercial systems, more rigorous engineering design, higher wind-load attachments and integrated metering/energy management are typically required.
Exceptions and Exemptions
- Existing PV or equivalent on-site generation: If the building already has PV installed covering at least 20% of roof area or has equivalent generation capacity elsewhere on site, the 20% reservation requirement does not apply. (NCC Volume One, J9D5.)
- Shading exemption: Where 100% of the roof area is shaded for more than 70% of daylight hours, the reserved area requirement is waived. Document shading analysis to justify this exemption.
- Battery provision exemption: Where a battery system is already installed or where the design clearly demonstrates equivalent future provision, some sizing/location requirements may be treated as satisfied. Check J9D5 wording and confirm with the relevant certifier.
- Small ancillary buildings: Very small roofs (for example roofs under thresholds specified in other NCC clauses or that are not practicable for PV) may be treated differently; always check the specific clause applicability and state schedules.
State and Territory Variations
- State schedules in the NCC and the ABCB Housing Provisions can modify or add requirements. The Housing Provisions Part 13 notes that state and territory variations, additions and deletions apply and that certain states use their own schemes (for example NSW uses BASIX to regulate some energy provisions). (See ABCB Housing Provisions Standard 2022, Part 13 and state schedule notes.)
- Examples:
- New South Wales: Some energy efficiency matters (Parts 13.3, 13.5 and 13.6) are regulated through BASIX rather than the Housing Provisions for NSW; check NSW schedule notes in the ABCB Housing Provisions. (ABCB Housing Provisions Standard 2022, NSW Part 13.1.2.)
- Other states: Each jurisdiction may include specific amendments in the NCC Volume One Schedules (Schedules 4-12). Always verify the relevant state schedule in NCC Volume One and the state section of the ABCB Housing Provisions before finalising design.
Practical Compliance Tips
- Document the 20% roof area: Provide a roof area plan showing the reserved 20% area, shading analysis and any existing PV or equivalent generation; include this in the building documentation submitted to the certifier to avoid delays.
- Follow AS/NZS 5033 and AS/NZS 3000: Ensure the electrical installer is licensed and that installation details, inverter siting, isolation, DC cabling and earthing arrangements comply with AS/NZS 5033 and the wiring rules in AS/NZS 3000.
- Design for wind and structural loads: Have a structural engineer or competent designer check roof fixings and framing for PV loads and wind actions per AS/NZS 1170.2; attach PV mounts through certified flashings and fasteners consistent with roofing manufacturer instructions.
- Plan for batteries and EVs early: Size switchboards and allocate spaces for future battery inverters, DC isolators and EV charging circuits during construction to minimise retrofit cost - align with NCC Volume One requirements for battery-ready and EV-ready provisions.
- Check state schedules and BASIX: Before issuing tender drawings, confirm any state-specific requirements or exemptions in the NCC schedules and, for NSW, whether BASIX imposes additional obligations on PV, energy targets or documentation.
- Avoid covering required fire elements: Do not locate PV arrays in a way that compromises fire separations, egress routes, or access for firefighters; consult the building certifier and relevant fire authority early where battery systems or large arrays are proposed.
- Keep records and product certification: Retain product technical data, wind-load calculations, installer certifications and electrical compliance certificates (e.g., Electrical Safety Certificates) and include references to applicable Australian Standards in the handover documentation.
- NCC 2022 Volume One - Building Code of Australia, J9D4 and J9D5 (roof area reservation, battery and EV provisions)
- ABCB Housing Provisions Standard 2022, Part 13 (energy efficiency, definitions, application) and state schedule notes (e.g., NSW Part 13.1.2)
- AS/NZS 5033 - Installation of photovoltaic (PV) arrays
- AS/NZS 3000 - Electrical installations (Wiring Rules)
- AS 4777.1 - Grid connection of energy systems via inverters
- AS/NZS 1170.2 - Structural design actions - Wind actions
- AS 4100 and AS 3700 where applicable for structural connections