Solar PV no longer a "get out of jail free card" in NCC 2025

NCC 2025: Why J1V3 Changes Will Put Façade Performance Front and Centre

For many project teams, J1V3 (Verification Method) has been the go-to pathway for achieving compliance under Section J.

Under NCC 2022, it provided flexibility — allowing designers to balance building fabric, services, and renewable energy to achieve an overall compliant outcome.

Under NCC 2025, that flexibility is being significantly reduced.

The result? Façade performance is no longer something that can be traded off — it must perform in its own right.

  • How could solar be previously used to "prop up" non-compliant fabric under NCC 2022?
  • No More Offsetting Poor Façade Performance with Solar PV
  • Higher Expectations for Glazing and Solar Control
  • External Shading Becomes a Key Design Requirement
  • What are the design implications for Project Teams?
  • What does this mean for your projects under NCC 2025?

How could solar be used to "prop up" non-compliant fabric under NCC 2022?

Using J1V3 under NCC 2022, many projects followed* a similar approach. Once the reference and proposed buildings were modelled, if the insulation and glazing didn't comply under J1V3, solar PV could be used to bridge the gap and offset the non-compliant building fabric. A building could require more energy than the NCC allowance in modelling, but a small solar system would generally produce enough onsite renewable energy to compensate for that and get the energy use of the proposed building lower than the reference building.

In practice, this meant:

👉 If the façade underperformed, it could often be compensated for elsewhere, with the trump card being that Solar PV could be used to get out of jail. (Interestingly this loophole was eliminated for Class 1 single dwellings with NCC 2019 in most states.)

This enabled:

  • Highly glazed architectural designs
  • Late-stage façade changes with manageable impact
  • Greater flexibility in balancing cost vs performance

Now, NCC 2025 fundamentally changes how J1V3 can be used.

* Please note that whilst we have used past tense for clarity, this approach can still be used in states and territories which have not yet adopted NCC 2025. Victoria has adopted NCC 2025 as of 1 May 2026 and the majority of the country is set to follow in the next 6-12 months.

1. No More Offsetting Poor Façade Performance with Solar PV

Under NCC 2025:

👉 On-site renewable energy (e.g. solar PV) cannot be used to compensate for poor building fabric performance under J1V3

This is a critical shift.

What it means:

  • PV contributes to overall emissions reduction
  • But it does not improve the baseline thermal performance of the building envelope

Impact:

  • Designs that previously relied on “add more PV” to achieve compliance will no longer work
  • Fabric performance must meet targets independently

2. Higher Expectations for Glazing and Solar Control

NCC 2025 places stronger emphasis on:

  • Lower U-values (better insulation performance)
  • Improved SHGC (solar heat gain control)
  • Reduced glazing reliance in some cases

But more importantly:

👉 Solar control is expected to be achieved through design — not just specification

3. External Shading Becomes a Key Design Requirement

Under NCC 2022:

  • External shading was often optional or value-engineered out

Under NCC 2025:

  • External shading is increasingly critical to achieving compliance

This includes:

  • Horizontal overhangs
  • Vertical fins
  • Screens and façade articulation

Why it matters:

  • Shading directly reduces solar heat gains
  • It improves façade performance without increasing mechanical loads

What This Means in Practice

The shift from NCC 2022 to NCC 2025 is not just technical — it’s behavioural. Under NCC 2022 project teams could keep the facade the way they wanted it and fix it later with J1V3 and solar PV. Under NCC 2025 the façade needs to work from day one. Shading and glazing need early resolution. Solar PV is a mandatory baseline provision — not a fallback strategy.

What are the design implications for Project Teams?

To adapt to NCC 2025, project teams will need to:

  • Engage earlier
    • ESD input at concept stage becomes essential
  • Lock in façade strategy sooner
    • Orientation, glazing ratios, and shading cannot be deferred
  • Rethink architectural intent
    • Highly glazed façades may require:
      • Better glass
      • More shading
      • Reduced glazing areas
    • Coordinate more closely
      • Architect, façade consultant, services engineer and ESD consultant must align early

What does this mean for your projects under NCC 2025?

NCC 2025 means that project teams can no longer design the façade last and solve it with modelling after the fact.

Instead:

  • The building envelope must be inherently high-performing
  • External shading will become a standard expectation, not an upgrade, for many designs in most climate zones
  • Renewable energy supports performance — but does not replace it

For project teams, success under NCC 2025 will come from getting the façade right early.

How can EcoResults help?

At EcoResults, we work with project teams to test façade options early, identify risks, and develop practical pathways to compliance under J1V3, whether or not solar PV is available as that "get out of jail free card".

With NCC 2025 tightening the rules around building fabric, early advice is critical to avoiding redesign and maintaining design intent.

If you’d like to understand how these changes affect your projects, our team is here to assist. We exist to make your life easier and contribute to the success of your projects. We will be happy to answer your questions and resolve any issues that these new changes bring.