NCC 2025 introduces important changes to J1V3 reference-building modelling for commercial and non-residential projects. These changes affect the performance threshold, envelope comparison, thermal-condition tests, climate data, operating profiles and treatment of on-site solar photovoltaic systems.
An NCC 2022 JV3 model cannot simply be carried forward and relabelled as an NCC 2025 assessment. The applicable code edition, jurisdiction and modelling basis should be confirmed before the model is updated. For a broader explanation of the underlying method, visit the JV3 Knowledge Hub.
In Brief
Under NCC 2025, the proposed building must satisfy an updated set of energy, envelope and internal-condition comparisons. The changes strengthen the performance benchmark and require project teams to revisit several inputs that may have been used in earlier JV3 models.
Energy Comparison
The proposed building must achieve annual greenhouse-gas emissions no greater than 97% of the reference-building result when proposed services are modelled.
Envelope Protection
A separate comparison using reference-building services maintains an independent check on building fabric and façade performance.
Internal Conditions
PMV, dry-bulb temperature or climate-zone-based peak-load criteria may apply, depending on the building and selected method.
Model Definition
Climate data, operating profiles, reference-building assumptions and solar PV require renewed attention under the updated methodology.
Performance Comparisons
The updated J1V3 method distinguishes between the overall performance of the proposed building and the underlying performance of its form, envelope and façade.
This prevents efficient services or renewable generation from carrying the entire result while the building fabric itself performs poorly.
Comparison One
The proposed building is assessed with its intended services strategy. Its annual greenhouse-gas emissions must be no more than 97% of the reference-building result.
Comparison Two
The proposed building is also assessed using the same services as the reference building. Its result must not exceed the corresponding reference-building outcome.
The 97% requirement applies to the proposed-services greenhouse-gas comparison. Envelope performance is protected through the separate same-services comparison.
Thermal Conditions
NCC 2025 provides several alternative ways to assess internal thermal conditions under J1V3. Project teams do not need to satisfy every method simultaneously.
For Class 5 buildings, the Predicted Mean Vote method remains available. Dry-bulb room-temperature criteria and climate-zone-based peak heating or cooling load comparisons provide alternative routes across the applicable building classes.
Class 5 Option
A PMV result between -1 and +1 must be achieved across at least 95% of occupied-zone floor area for at least 98% of annual operating hours.
Temperature Option
Relevant occupied areas must remain within the prescribed temperature ranges for at least 95% of annual operating hours across at least 95% of occupied-zone floor area.
Load Option
Peak zone heating or cooling loads are compared with corresponding reference-building zones using limits that vary by NCC climate zone.
| Method | Criterion | Application |
|---|---|---|
| PMV | Between -1 and +1. | Available for Class 5 buildings, subject to the required occupied-area and annual-hours coverage. |
| Dry-bulb temperature | 18°C to 25°C for transitory occupancy and 21°C to 24°C for other conditioned spaces. | Applied across the required proportion of occupied-zone floor area and annual operating hours. |
| 98th-percentile load | 110% limits in climate zones 1 and 8; 120% heating and cooling limits in climate zones 2 to 7. | Assessed against the corresponding reference-building zones across 95% of assessable floor area. |
Updated Modelling Basis
The J1V3 changes are not limited to the performance comparisons. The modelling specifications also update several inputs used to construct and operate the proposed and reference models.
Assumptions from an NCC 2022 model should therefore be checked rather than carried forward automatically.
Climate Files
The updated climatic-data requirements influence the conditions against which future building performance is assessed.
Operating Profiles
Updated lighting, occupancy and air-conditioning profiles affect selected building classifications and should be checked when constructing the annual model.
Renewable Energy
Where solar PV is required for the reference building, proposed generation is no longer compared against a benchmark without corresponding renewable generation.
Thermal Zones
The thermal-condition tests increase the importance of representing perimeter exposure, internal areas and distinct operating conditions at an appropriate zone level.
Project Implications
The updated methodology places greater emphasis on the relationship between envelope performance, services strategy and zone-level internal conditions.
Confirm the jurisdiction, applicable NCC edition, transition arrangements and relevant building classifications before setting up the models.
Review glazing, orientation, shading, frame performance and opaque-envelope construction against both required comparisons.
Ensure the zoning strategy represents different orientations, uses, schedules and operating conditions without masking local performance concerns.
Coordinate air-conditioning, ventilation, lighting, controls and renewable-energy systems with the architectural and façade design.
Review NCC 2022 models against the updated climate data, profiles, comparison thresholds, reference-building inputs and thermal-condition tests.
Application and Transition
No. The NCC is given legal effect through state and territory legislation, and adoption dates and transition arrangements can differ. A project should not move to the NCC 2025 methodology solely because it is the latest nationally published edition.
The J1V3 provisions discussed here apply to relevant Class 3 and Class 5 to 9 buildings. Class 2 requirements should be considered separately.
For broader context on commercial energy-efficiency changes across recent NCC editions, read how Section J changed across NCC 2019, 2022 and 2025.
Before modelling begins, the project team should confirm the applicable NCC edition with the relevant building surveyor, certifier or approval authority.
Frequently Asked Questions
For the proposed-services greenhouse-gas comparison, the proposed building must achieve no more than 97% of the reference-building result. This represents a minimum 3% margin below that benchmark.
Has PMV been removed from J1V3?No. PMV remains an available thermal-condition method for Class 5 buildings. NCC 2025 also provides dry-bulb room-temperature and climate-zone-based peak-load alternatives.
Can efficient mechanical systems compensate for a weak envelope?Not without limitation. The proposed building is separately compared using the same services as the reference building, maintaining an independent check on building fabric, glazing and shading.
Can solar PV resolve any J1V3 result?No. Solar generation can form part of the overall strategy, but the reference-building methodology and same-services comparison limit the extent to which it can compensate for underperforming envelope design.
Can an NCC 2022 JV3 model be reused?Existing geometry and coordinated project information may remain useful, but the model should be reviewed against the complete NCC 2025 methodology. Climate data, profiles, reference-building inputs, comparison thresholds and thermal-condition criteria may need to be updated.
How do I know which NCC edition applies?The applicable edition depends on the project jurisdiction, approval timing and any state or territory transition provisions. The regulatory basis should be confirmed before the models are finalised.
Related Knowledge
Explore the underlying modelling method, the broader Section J framework and the choice between prescriptive and performance-based compliance.
Technical Foundation
Understand proposed and reference buildings, modelling inputs, performance comparisons, safeguards and documentation requirements.
Parent Framework
Review the wider commercial energy-efficiency framework, its scope, applicable NCC editions and compliance approaches.
Code Changes
Review the broader evolution of commercial energy-efficiency provisions across NCC 2019, NCC 2022 and NCC 2025.
Pathway Comparison
Compare the prescribed Deemed-to-Satisfy provisions with J1V3 reference-building modelling.
Regulatory Note
This article provides general technical guidance and should be read alongside the complete NCC provisions and the adoption arrangements applying in the relevant state or territory. Project-specific requirements should be confirmed with the relevant approval authority.
JV3 Project Review
Certified Energy can review the project location, applicable NCC edition, architectural documentation and available façade and services information.
This can help establish whether an existing model needs to be updated and what information is required to progress an NCC 2025 J1V3 assessment.
Request a JV3 Project ReviewLast reviewed: June 2026