NCC 2025 introduces important changes to J1V3 reference-building modelling for commercial and non-residential projects. The changes affect the performance threshold, envelope comparison, thermal-condition tests, climate data, operating profiles and treatment of on-site solar photovoltaic systems.
For architects, developers, building surveyors and services consultants, this means 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 need to be confirmed before the proposed and reference buildings are developed.
In Brief
What Changes for J1V3 Under NCC 2025?
JV3 remains the commonly used industry term, while J1V3 is the formal NCC reference for the Verification Method. Under NCC 2025, the proposed building must satisfy a more clearly defined set of energy, envelope and internal-condition comparisons.
The principal change is that the annual greenhouse-gas emissions of the proposed building must be no more than 97% of the reference-building result when proposed services are modelled. A separate same-services comparison remains, together with thermal-condition criteria and additional modelling requirements.
Energy Comparison
97% threshold
The proposed building must achieve annual greenhouse-gas emissions no greater than 97% of the reference-building result.
Envelope Protection
Same-services check
The proposed building is also assessed using the same services as the reference building to maintain a distinct check on fabric performance.
Internal Conditions
Alternative comfort tests
PMV, dry-bulb temperature or climate-zone-based peak-load criteria may apply, depending on the building and selected method.
Model Definition
Updated inputs
Climate data, operating profiles, reference-building assumptions and solar PV require renewed attention under the updated methodology.
Performance Threshold
The Proposed Building Must Achieve 97% or Less
Under NCC 2025 J1V3, the annual greenhouse-gas emissions of the proposed building must be no more than 97% of the annual greenhouse-gas emissions produced by the reference building when the proposed building is modelled with its proposed services.
In practical terms, simply matching the reference-building result is no longer sufficient for this comparison. The proposed building must demonstrate a minimum margin below the benchmark.
This can affect the balance between façade design, insulation, glazing, shading, mechanical systems, lighting, controls and renewable-energy inputs. Project teams may need to coordinate these elements earlier rather than relying on a late modelling exercise to resolve the result.
This is not a 3% envelope margin
The 97% requirement applies to the annual greenhouse-gas comparison using proposed services. Envelope performance is protected through a separate comparison in which the proposed building is modelled using the same services as the reference building.
Envelope Safeguard
Why Efficient Services Cannot Carry the Entire Result
J1V3 retains a separate comparison intended to prevent weak envelope performance from being masked by efficient mechanical systems, controls or renewable-energy generation.
For this check, the proposed building is modelled using the same services as the reference building. The resulting annual greenhouse-gas emissions must not exceed the corresponding reference-building result.
Comparison One
Proposed services
Tests the proposed building, including its intended services strategy, against the reference-building greenhouse-gas benchmark. The result must be no more than 97% of the reference result.
Comparison Two
Reference services
Tests the proposed building using the same services as the reference building. This isolates the effect of the building form, envelope, glazing and shading more clearly.
Thermal Conditions
PMV Has Not Simply Been Removed
NCC 2025 provides several ways to assess internal thermal conditions under J1V3. These are alternative compliance tests rather than a requirement 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
Predicted Mean Vote
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
Dry-bulb temperature
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
98th-percentile zone loads
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
Climate Data, Operating Profiles and Solar PV
The J1V3 changes are not limited to the headline 97% comparison. The modelling specifications also update several inputs used to construct and operate the proposed and reference models.
These changes mean assumptions from an existing NCC 2022 model should not be carried forward automatically. The climate files, schedules, reference-building properties and services inputs should be checked against the NCC edition governing the project.
Climate Files
Future climate data
The modelling methodology introduces updated climatic-data requirements intended to represent the conditions against which future building performance is assessed.
Operating Profiles
Revised schedules
Updated lighting, occupancy and air-conditioning profiles affect selected building classifications and should be checked when constructing the annual model.
Renewable Energy
Reference-building solar PV
Where the NCC methodology requires solar PV for the reference building, proposed solar generation is no longer being compared against a benchmark without corresponding renewable generation.
Façade Definition
Wall-glazing calculations
The modelling provisions interact with updated methods for defining wall-glazing U-Values, solar admittance, façade orientation and shading performance.
Thermal Zones
Zone-level performance
The thermal-condition tests increase the importance of representing perimeter exposure, internal areas and distinct operating conditions at an appropriate zone level.
Project Evidence
Updated documentation
The report, model inputs, drawings and specifications should identify the code edition and remain aligned with the building assessed under the updated methodology.
Project Implications
What Project Teams Should Review Earlier
The updated J1V3 methodology places greater emphasis on the relationship between the building envelope, services strategy and zone-level internal conditions. Design teams may need to consider the modelling basis before key façade and services decisions become difficult to change.
Code basis
Confirm the jurisdiction, applicable NCC edition, transition arrangements and relevant building classifications before setting up the models.
Façade design
Review glazing area, orientation, shading, frame performance and opaque-envelope construction against both the energy comparison and separate envelope safeguard.
Thermal zoning
Ensure the zoning strategy can represent different orientations, perimeter conditions, uses, schedules and services without masking local performance concerns.
Services strategy
Coordinate proposed air-conditioning, ventilation, lighting, controls and renewable-energy systems with the architectural and façade design.
Existing models
Review existing NCC 2022 models against the NCC 2025 climate data, profiles, comparison thresholds, reference-building inputs and thermal-condition tests.
Application and Transition
Does NCC 2025 Apply to Every JV3 Project?
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 in this article apply to relevant Class 3 and Class 5 to 9 buildings. Proposed NCC 2025 Section J changes for Class 2 buildings did not proceed, and Class 2 requirements should be considered separately.
Before modelling begins, the project team should confirm the applicable NCC edition with the relevant building surveyor, certifier or approval authority and document that basis consistently across the assessment.
Frequently Asked Questions
NCC 2025 J1V3 FAQs
Does the 97% requirement mean the proposed building must perform 3% better?
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. This maintains an independent check on building form, fabric, glazing and shading performance.
Can solar PV be used to resolve any J1V3 result?
No. Solar generation can form part of the overall energy strategy, but the reference-building methodology and same-services comparison limit the extent to which renewable generation can compensate for underperforming envelope design.
Can an NCC 2022 JV3 model be reused?
The existing geometry and coordinated project information may remain useful, but the model should be reviewed against the full 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 proposed and reference models are finalised.
Related Knowledge
Continue Exploring JV3 and Section J
Explore the underlying JV3 methodology, the broader Section J framework and the differences between prescriptive and modelling-based compliance pathways.
Technical Foundation
JV3 Knowledge Hub
Understand proposed and reference buildings, modelling inputs, performance comparisons, safeguards and documentation requirements.
Parent Framework
Section J Knowledge Hub
Review the wider commercial energy-efficiency framework, scope, NCC editions and principal compliance approaches.
Pathway Comparison
Section J DTS vs JV3
Compare the prescribed Deemed-to-Satisfy provisions with J1V3 reference-building modelling and understand pathway-selection considerations.
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
Is Your Commercial Project Moving to NCC 2025?
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
