Who it covers, and who it does not
Section J of NCC 2025 applies to Class 3 and Class 5 to 9 buildings — the ABCB lists hotels, offices, retail, hospitals and schools — along with Class 4 parts of those buildings. Warehouses, factories, childcare and aged care all sit inside that range.
Class 2 is the exception. For apartment buildings, NCC 2025 does not carry its own Section J: it points back to Section J of NCC 2022 Amendment 2. An apartment building permitted under NCC 2025 is still assessed against the 2022 energy provisions, so none of the changes below apply to it. Mixed-use buildings need care, because the apartments and the shops or offices below them can sit under different Section J text in the same permit set.
Detached houses and townhouses are NCC Volume Two and outside Section J altogether. They need a residential energy report instead.
When it applies
Victoria adopted NCC 2025 on 1 May 2026, with no transition period. Western Australia and the ACT adopted it from the same date with a 12-month transition. New South Wales, Queensland, South Australia and Tasmania adopt it from 1 May 2027, and the Northern Territory has not adopted it.
The edition that applies is the one in force when the building permit is issued, not when the report is written. That matters for drawings assessed last year and not yet lodged: a glazing specification that passed under NCC 2022 does not necessarily pass under 2025, so the report is redone against the current edition before the permit goes in.
Behind every change below sits a tighter performance requirement. In the ABCB’s words, under J1P1 “the regulated energy allowance has been roughly halved, and greenhouse gas emissions are now quantified.” Most projects never meet that requirement directly — they use the Deemed-to-Satisfy provisions — and those provisions were strengthened with it.
Part J4: roofs, walls and glazing
Roofs: colour now has to be backed by data
NCC 2022 capped roof solar absorptance at 0.45 in climate zones 1 to 7. NCC 2025 replaces that single limit in J4D4 with a choice: a total solar reflectance above 0.55, a solar reflectance index above 61, or a solar absorptance of 0.45 or less combined with a thermal emittance above 0.85. Metal roofs near air intakes get stricter values. Class 3, 9c and 9a ward buildings also get their own, higher set of roof R-Values.
On the drawings, that means naming the roofing product and keeping its data sheet with the set. “Light colour roof” is no longer something a report can work from.
Wall-glazing (J4D6): solar admittance and U-Values per climate zone
The ABCB’s summary names stricter solar admittance criteria for wall-glazing constructions. In the code itself, the total system U-Value limit is not new, but it moves into its own table (Table J4D6a) and is set per climate zone — 1.6 to 2.0 for the Class 5 group and 1.1 to 1.6 for the Class 3 group. Every other J4D6 table moves down a letter as a result, which is worth knowing when a 2022 report is being compared with a 2025 one.
The minimum wall R-Values, now in Table J4D6b, change in every climate zone. For the Class 5 group, climate zone 8 goes from R1.4 to R3.6. Specification 37, the method behind the facade calculator, adds new shading multiplier tables for vertical shading devices.
In practice: the window schedule needs the manufacturer’s U-Value and SHGC for every glazed system, as before, and any glazing specified to a 2022 facade calculation needs checking again. The earlier that happens, the more likely the fix is a glass specification rather than a change to the elevations.
J9D5: solar has to be installed
Under NCC 2022, J9D5 asked for readiness: at least 20 per cent of the roof left clear, and switchboard provision for a future system. NCC 2025 J9D5 requires buildings to install solar PV, “rather than only providing space for future installation”, as the ABCB puts it. This applies to Class 3 and Class 5 to 9 buildings.
The minimum is either the whole of the eligible roof area, or a PV capacity per square metre of conditioned space set in Table J9D5a, with more added under Table J9D5b for buildings that use gas. Of all the changes, this is the one most likely to surprise a client late, because it lands on the roof plan and the electrical drawings, not just in the report.
Related to it: J6D10 and Part J8 now ask for buildings to be designed so gas systems can more easily be replaced with electric ones — electrical capacity, switchboard space, risers and plant space. Heavy gas plant on a new commercial job is worth a conversation before the services drawings are done.
Lighting, air-conditioning and hot water
Lighting (J7)
The illumination power density table barely moved: the only value change between 2022 and 2025 is lift cars, from 3 to 5.5 W/m². The controls are what changed. J7D4 now makes demand-operated controls, to Specification 40, the default for lighting, and introduces a definition of “regular occupancy”. The ABCB describes the result as broader control requirements with more flexibility in how they are designed. A fitout lighting schedule without a controls column will come back with questions.
Air-conditioning and ventilation (J6)
Requirements are enhanced for chillers, heat pumps, air conditioners, fans, pumps and cooling towers. The mechanical schedule needs to carry the efficiency data for each.
Hot water (J8) — a numbering trap
NCC 2025 inserts a new J8D2, “Application of Part”, which pushes heated water supply from J8D2 in 2022 to J8D3 in 2025. In a 2022 report, J8D3 means swimming pool heating and pumping. When comparing reports across editions, check the clause against the edition, not the number alone.
Energy monitoring (J9D3)
The metering thresholds are unchanged — time-of-use metering above 500 m² and sub-metering above 2,500 m² — and NCC 2025 adds an optional route to comply through an Environmental Management Information System.
What to change on the drawings
For a Class 3 or 5 to 9 project going to a Victorian building permit now, this is the short list:
- Confirm the edition from when the permit will be issued. Anything assessed under NCC 2022 and not yet permitted gets redone against 2025.
- Roof: name the roofing product and keep its reflectance and emittance data with the set.
- Glazing: a window schedule with the manufacturer’s U-Value and SHGC per system. Re-check any glazing carried over from a 2022 report.
- Walls: check the build-ups against the new minimum R-Values for the climate zone.
- Roof plan: show the solar PV array, sized to the J9D5 minimum.
- Electrical and mechanical: switchboard, riser and plant space for electrification, the lighting control schedule, and efficiency data for the air-conditioning plant.
- Class 2 parts: flag them. Apartments stay on NCC 2022’s Section J.
Sources: ABCB, NCC 2025 commercial energy efficiency changes and state and territory adoption information; NCC 2025 Volume One, Section J. This guide is general information, not an assessment of any particular building.